External quality assurance in the era of standardization

Metrology in clinical chemistry aims to ensure the equivalence of measurement results from different in-vitro diagnostic measurement devices (IVD MD) for use in healthcare. The metrological traceability of measurement results to higher-order references is the cornerstone to achieving equivalent results. However, other fundamentals are also needed, including the commutability of reference materials and external quality assessment (EQA) materials for monitoring the equivalence of measurement results at the end-user level. This manuscript summarizes the findings and opinions expressed at the Joint Community for Traceability in Laboratory Medicine (JCTLM) workshop held on December 4-5, 2023. The workshop explored the relationship between EQA/proficiency testing and metrological traceability to higher-order references. EQA monitors the equivalence of measurement results from end-user IVD MDs. The workshop discussed the role and challenges of using EQA to improve and maintain the equivalence of measurement results. It also elucidated current developments in establishing the clinical suitability of laboratory results expressed as analytical performance specifications (APS).

The LEAP checklist for laboratory evaluation and analytical performance characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

The LEAP Checklist for Laboratory Evaluation and Analytical Performance Characteristics Reporting of Clinical Measurement Procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the Laboratory Evaluation and Analytical Performance Characteristics (LEAP) checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

Clot time ratio (CTR) and relation to treatment outcome in patients with atrial fibrillation treated with Rivaroxaban

BACKGROUND

There are situations where information about the anticoagulant effects of Rivaroxaban could be clinically useful. Methods for measuring Rivaroxaban concentrations are not available at all medical laboratories while the test MRX PT DOAC for measuring the functional effects of Rivaroxaban, in CTR (Clot Time Ratio), can be made available around the clock. The objectives of this study were to investigate CTR in trough and peak samples during Rivaroxaban treatment of atrial fibrillation and to correlate the findings to bleeding episodes.

METHODS

3 trough- and 3 peak samples from 60 patients (30 on 20 mg daily and 30 on 15 mg daily) were analyzed with PT DOAC. Patients were monitored for 20 months, and bleeding and thrombotic events were documented. Descriptive statistics were used to summarize the data and non-parametric t-test for comparison between groups. ROC curves for the prediction of DOAC plasma levels > 50 ng/mL as determined with LC-MS/MS and anti-FXa methods were computed.

RESULTS

There was a significant difference between trough and peak CTR (median CTR 1.33 vs. 3.57, p < 0.001). 28 patients suffered bleeds. Patients on 20 mg Rivaroxaban with bleeds had higher mean peak CTR than patients without bleeds (CTR 4.11 vs. CTR 3.47, p = 0.040). There was no significant difference in mean CTR between patients on 15 mg Rivaroxaban with or without bleeds (CTR 3.81 vs. 3.21, p = 0.803), or when considering all patients (CTR 3.63 vs. 3.56, p = 0.445). Five out of seven patients on Rivaroxaban 20 with mean peak CTR above the dose specific first to third quartile range (Q1-Q3) suffered bleeds, while 7/16 patients with mean peak CTR within, and 1/7 patients with mean peak CTR below the Q1-Q3 suffered bleeds. The area under the ROC curve was > 0.98 at the upper limit of the PT DOAC reference interval and the negative predictive value of PT DOAC for the prediction of DOAC plasma levels > 50 ng/mL was > 0.96.

CONCLUSIONS

The sample size was too low to draw any firm conclusions but is seems that MRX PT DOAC might be a useful laboratory test in situations where the effect of Rivaroxaban needs evaluation.

Robot-assisted pelvic and renal surgery compared with laparoscopic or open surgery: Literature review of cost-effectiveness and clinical outcomes

BACKGROUND AND AIM

The purpose of this study was to evaluate clinical experiences and cost-effectiveness by comparing robot-assisted surgery with laparoscopic- or open surgery for pelvic and renal operations.

METHODS

A narrative review was carried out.

RESULTS

When using robotic-assisted surgery, oncological and functional results are similar to after laparoscopic or open surgery. One exception may be a shorter survival in cancer of the cervix uteri. In addition, postoperative complications after robotic-assisted surgery are similar, bleeding and transfusion needs are less, and the hospital stay is shorter but the preparation of the operating theater before and after surgery and the operation times are longer. Finally, robot-assisted surgery has, in several studies, been reported to be not cost-effective primarily due to high investment costs. However, more recent studies provide improved cost-effectiveness estimates due to more effective preparation of the operating theater before surgery, improved surgeon experience, and decreased investment costs.

CONCLUSIONS

Complications and functional and oncological outcomes after robot-assisted surgery are similar to open surgery and laparoscopic surgery. The cost-effectiveness of robot-assisted surgery is likely to equal or surpass the alternatives.

Issues in assessing analytical performance specifications in healthcare systems assembling multiple laboratories and measuring systems

Analytical performance specifications (APS) are usually compared to the intermediate reproducibility uncertainty of measuring a particular measurand using a single in vitro diagnostic medical device (IVD MD). Healthcare systems assembling multiple laboratories that include several IVD MDs and cater to patients suffering from long-term disease conditions mean that samples from a patient are analyzed using a few IVD MDs, sometimes from different manufacturers, but rarely all IVD MDs in the healthcare system. The reproducibility uncertainty for results of a measurand measured within a healthcare system and the components of this measurement uncertainty is useful in strategies to minimize bias and overall measurement uncertainty within the healthcare system. The root mean squares deviation (RMSD) calculated as the sample standard deviation (SD) and relative SD includes both imprecision and bias and is appropriate for expressing such uncertainties. Results from commutable stabilized internal and external control samples, from measuring split natural patient samples or using big-data techniques, are essential in monitoring bias and measurement uncertainties in healthcare systems. Variance component analysis (VCA) can be employed to quantify the relative contributions of the most influential factors causing measurement uncertainty. Such results represent invaluable information for minimizing measurement uncertainty in the interest of the healthcare system's patients.

Expression of calcitonin gene-related peptide in atopic dermatitis and correlation with distress

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory, often severely itching skin disorder. It may worsen due to stress, depression, or anxiety. Calcitonin gene-related peptide (CGRP) may be involved in inflammation signaling. CGRP has also been suggested in relation to stress, depression, and anxiety. This study aimed to investigate the expression of CGRP in the skin of patients with AD.

METHODS

Twenty-seven adult patients with AD, characterized with clinical and psychodemographic parameters, were investigated regarding CGRP expression in skin biopsies, using an immunohistochemical technique.

RESULTS

The total number of CGRP-positive nerve-like fibers was found to be higher in lesional skin than in non-lesional skin. Moreover, more inflammatory cells of dendritic shape intruded into the epidermis in lesional skin compared to non-lesional skin. Keratinocytes showing expression of CGRP were also found in lesional skin. Interestingly, the number of CGRP-positive nerve-like fibers in lesional skin correlated with depressive and anxiety scores. Correlation with depressive score was also found for round CGRP-positive inflammatory cells in the epidermis.

CONCLUSIONS

CGRP may have a role in both the inflammatory process and distress, in AD.

The LEAP checklist for laboratory evaluation and analytical performance characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

The LEAP checklist for Laboratory Evaluation and Analytical Performance characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

The LEAP checklist for Laboratory Evaluation and Analytical Performance Characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript.The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

Excessive hair cortisol concentration as an indicator of psychological disorders in children

Cortisol in hair is a new biomarker assessing long-term hypothalamic-pituitary-adrenal (HPA) axis activity, which is related to emotion regulation. We compare hair cortisol concentrations (HCC), in clinically referred children with disruptive mood dysregulation disorder (DMDD) (n = 19), children with other types of psychological disorders (n = 48), and healthy subjects (n = 36). We also investigate the association between HCC and irritability, age, and sex. Our results show that children with DMDD or other types of psychological disorders have higher HCC than healthy subjects, p < .001, ηp2 = .39. No difference between children with DMDD and those with other types of psychological disorders was found, p = .91, nor an association between HCC and irritability in the clinical sample, p = .32. We found a significant negative correlation between HCC and age in those with DMDD, r = -0.54, p < .05, but not in the normative sample, r = -0.20, p = .25. No differences in HCC between girls and boys were found in the normative sample, p = .49. Children in need of psychological treatment, including those with DMDD, seem to have dysregulated HPA-axis activity over time. Excessive accumulated cortisol concentrations in hair could be an indicator of a psychological disorder in children.

The LEAP checklist for laboratory evaluation and analytical performance characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the Laboratory Evaluation and Analytical Performance Characteristics (LEAP) checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

The LEAP checklist for laboratory evaluation and analytical performance characteristics reporting of clinical measurement procedures

Reporting a measurement procedure and its analytical performance following method evaluation in a peer-reviewed journal is an important means for clinical laboratory practitioners to share their findings. It also represents an important source of evidence base to help others make informed decisions about their practice. At present, there are significant variations in the information reported in laboratory medicine journal publications describing the analytical performance of measurement procedures. These variations also challenge authors, readers, reviewers, and editors in deciding the quality of a submitted manuscript. The International Federation of Clinical Chemistry and Laboratory Medicine Working Group on Method Evaluation Protocols (IFCC WG-MEP) developed a checklist and recommends its adoption to enable a consistent approach to reporting method evaluation and analytical performance characteristics of measurement procedures in laboratory medicine journals. It is envisioned that the LEAP checklist will improve the standardisation of journal publications describing method evaluation and analytical performance characteristics, improving the quality of the evidence base that is relied upon by practitioners.

Effect of cosmetic hair treatment and natural hair colour on hair testosterone concentrations

PURPOSE

Testosterone analysis in hair allows for retrospective evaluation of endogenous testosterone concentrations, but studies devoted to investigating confounders in hair testosterone analysis have hitherto been scarce. The current study examined the stability of testosterone concentrations between two hair samples collected three months apart and investigated two potential confounding factors: natural hair colour and cosmetic hair treatments.

METHODS

Testosterone was analysed with an in-house radioimmunoassay with a limit of detection adequate for the purpose.

RESULTS

The testosterone concentrations from the two samplings, at baseline and three months later, had an intra-individual correlation of moderate strength (rho = 0.378, p<0.001, n = 146). Hair treatment, such as colouring or bleaching, seemed to increase testosterone concentrations (p = 0.051, n = 191, and in a paired analysis in a subset of the cohort p = 0.005, n = 24), while no effect of natural colour in untreated hair (p = 0.133) could be detected.

CONCLUSION

The current results suggest that cosmetic hair treatments need to be considered in hair testosterone analyses and demonstrate the utility of a radioimmunoassay to reliably measure testosterone concentrations in small hair samples in women.

Segmental hair analysis as a retrospective testosterone diary: possibilities and pitfalls

Testosterone is thought to be incorporated in growing hair strands so that specific hair segments reflect average free hormone concentrations from the corresponding time period. However, the exact mechanisms of hormone integration in scalp hair have not yet been established and it is not known how testosterone is stored in the hair segments over time. The aim of this study was to investigate the stability of testosterone concentrations in hair as it grows and to determine if segmental hair analysis can be used as a retrospective testosterone diary. Thirty men and 40 women provided two hair samples and 16 saliva samples during a period of three months. Hair growth between the two samplings was measured. Hair samples were cut into 10 mm segments resulting in three segments from the first sampling and six segments from the second sampling. Hair samples were pulverised and extracted with methanol. Hair testosterone concentrations were analysed using an in-house radioimmunoassay. Salivary testosterone was analysed using a commercial enzyme-linked immunosorbent assay (Demeditec). The results demonstrated that there is a degree of segmental hormone conservation over time (rho = 0.405-0.461, p < 0.001, n = 66-67), but also highlighted three potential confounders. Firstly, testosterone concentrations were higher in distal hair segments (mean concentration ratio most distal by most scalp-near was 1.55, SD 0.70), which may be due to continuous hormone integration from sebum and changes in hair matrix composition. Secondly, more frequent hair washing stunted the increase in testosterone concentrations in distal segments (rho = -0.404, p =  < 0.001, n = 66). And lastly, intra- and inter- individual variability in hair growth rate influenced the temporal resolution along the hair, although mean growth rate was indeed 30.0 mm for three months. In a multiple regression model the biological sex, natural hair colour, and relationship status were significant explanatory variables to hair testosterone concentrations. The current results indicate that repeated hair sampling near the hair roots during a study may be preferable to analysing concentration changes between proximal and distal segments within the same hair sample. Also, hair testosterone analysis needs to be adjusted for sex and the natural hair colour.

Epigenetic modifications appear in the human placenta following anxiety and depression during pregnancy

INTRODUCTION

The future health of the offspring can be influenced by longstanding maternal anxiety and depression disorders during pregnancy. The present study aimed to explore the effect of psychiatric disorders during pregnancy on placental epigenetics.

METHODS

We measured DNA methylation patterns in term-placentas of women either suffering longstanding anxiety and depression symptoms (Index group, with overt symptoms), or a healthy population (Control, none/only mild symptoms). Whole genome DNA methylation profiling was performed using the TruSeq® Methyl Capture EPIC Library Prep Kit (Illumina, San Diego, CA, USA) for library preparation and NGS technology for genomic DNA sequencing.

RESULTS

The results of high-throughput DNA methylation analysis revealed that the Index group had differential DNA methylation at epigenome-wide significance (p < 0.05) in 226 genes in the placenta. Targeted enrichment analyses identified hypermethylation of genes associated with psychiatric disorders (BRINP1, PUM1), and ion homeostasis (COMMD1), among others. The ECM (extracellular matrix)-receptor interaction pathway was significantly dysregulated in the Index group compared to the Control. In addition, DNA methylation/mRNA integration analyses revealed that four genes with key roles in neurodevelopment and other important processes (EPB41L4B, BMPR2, KLHL18, and UBAP2) were dysregulated at both, DNA methylation and transcriptome levels in the Index group compared to Control.

DISCUSSION

The presented results increase our understanding of how maternal psychiatric disorders may affect the newborn through placental differential epigenome, suggesting DNA methylation status as a biomarker when aiming to design new preventive techniques and interventions.

Work-related factors and hair cortisol concentrations among men and women in emergency medical services in Sweden

Ambulance personnel in emergency medical services are exposed to physical demands and stress during work, and an increased prevalence of ill health has been observed in this group. The aim was to compare hair cortisol concentration (HCC) among Swedish ambulance personnel with HCC in a population-based reference sample, to analyse differences between women and men, and differences due to work-related factors. Samples of hair 1 cm closest to the skin (5-10 mg) were collected and analysed for cortisol by radioimmunoassay. Moreover, the participants responded to a questionnaire regarding their work environment. The HCC among the ambulance personnel did not differ from the HCC in the population-based reference sample (median 19.2 vs. 22.2 pg/mg, p = 0.319), nor were there statistically significant differences between women and men. Furthermore, no associations were found between HCC and physical and psychosocial work demands, work stress, or rest and recovery from work. However, occupational balance was positively correlated with HCC (rp = 0.240; p = 0.044). The association remained statistically significant after adjustment for sex, age, hair bleaching, and corticosteroid treatment in a linear regression model. This study adds knowledge regarding HCC among ambulance personnel, and thus contributes to the overall picture of work environment and health for this group.

Distribution, cellular localization, and colocalization of several peptide neurotransmitters in the central nervous system of Aplysia

Neuropeptides are widely used as neurotransmitters in vertebrates and invertebrates. In vertebrates, a detailed understanding of their functions as transmitters has been hampered by the complexity of the nervous system. The marine mollusk Aplysia, with a simpler nervous system and many large, identified neurons, presents several advantages for addressing this question and has been used to examine the roles of tens of peptides in behavior. To screen for other peptides that might also play roles in behavior, we observed immunoreactivity in individual neurons in the central nervous system of adult Aplysia with antisera raised against the Aplysia peptide FMRFamide and two mammalian peptides that are also found in Aplysia, cholecystokinin (CCK) and neuropeptide Y (NPY), as well as serotonin (5HT). In addition, we observed staining of individual neurons with antisera raised against mammalian somatostatin (SOM) and peptide histidine isoleucine (PHI). However, genomic analysis has shown that these two peptides are not expressed in the Aplysia nervous system, and we have therefore labeled the unknown peptides stained by these two antibodies as XSOM and XPHI There was an area at the anterior end of the cerebral ganglion that had staining by antisera raised against many different transmitters, suggesting that this may be a modulatory region of the nervous system. There was also staining for XSOM and, in some cases, FMRFamide in the bag cell cluster of the abdominal ganglion. In addition, these and other studies have revealed a fairly high degree of colocalization of different neuropeptides in individual neurons, suggesting that the peptides do not just act independently but can also interact in different combinations to produce complex functions. The simple nervous system of Aplysia is advantageous for further testing these ideas.

Clinical decision limits as criteria for setting analytical performance specifications for laboratory tests

BACKGROUND

The biological (CV_I), preanalytical (CV_PRE), and analytical variation (CV_A) are inherent to clinical laboratory testing and consequently, interpretation of clinical test results.

METHODS

The sum of the CV_I, CV_PRE, and CV_A, called diagnostic variation (CV_D), was used to derive clinically acceptable analytical performance specifications (CAAPS) for clinical chemistry measurands. The reference change concept was applied to clinically significant differences (CD) between two measurements, with the formula CD = z*√2* CV_D. CD for six measurands were sought from international guidelines. The CAAPS were calculated by subtracting variances of CV_I and CV_PRE from CV_D. Modified formulae were applied to consider statistical power (1-β) and repeated measurements.

RESULTS

The obtained CAAPS were 44.9% for urine albumin, 0.6% for plasma sodium, 22.9% for plasma pancreatic amylase, and 8.0% for plasma creatinine (z = 3, α = 2.5%, 1-β = 85%). For blood HbA_1c and plasma low-density lipoprotein cholesterol, replicate measurements were necessary to reach CAAPS for patient monitoring. The derived CAAPS were compared with analytical performance specifications, APS, based on biological variation.

CONCLUSIONS

The CAAPS models pose a new tool for assessing APS in a clinical laboratory. Their usability depends on the relevance of CD limits, required statistical power and the feasibility of repeated measurements.

Performance specifications for sodium should not be based on biological variation

When increasing the quality in clinical laboratories by decreasing measurement uncertainty, reliable methods are needed not only to quantify the performance of measuring systems, but also to set goals for the performance. Sigma metrics used in medical laboratories for documenting and expressing levels of performance, are evidently totally dependent on the "total permissible error" used in the formulas. Although the conventional biological variation (BV) based model for calculation of the permissible (or allowable) total error is commonly used, it has been shown to be flawed. Alternative methods are proposed, mainly also based on the within-subject BV. Measurement uncertainty models might offer an alternative to total error models. Defining the limits for analytical quality still poses a challenge in both models. The aim of the present paper is to critically discuss current methods for establishing performance specifications by using the measurement of sodium concentrations in plasma or serum. Sodium can be measured with high accuracy but fails by far to meet conventional performance specifications based on BV. Since the use of sodium concentrations is well established for supporting clinical care, we question the concept that quality criteria for sodium and similar analytes that are under strict homeostatic control are best set by biology.

Sex Hormones and Adrenal Steroids: Biological Variation Estimated Using Direct and Indirect Methods

BACKGROUND

Biological variation (BV) data may be used to develop analytical performance specifications (APS), reference change values (RCV), and support the applicability of population reference intervals. This study estimates within-subject BV (CVI) for several endocrine biomarkers using 3 different methodological approaches.

METHODS

For the direct method, 30 healthy volunteers were sampled weekly for 10 consecutive weeks. Samples were analyzed in duplicate for 17-hydroxyprogesterone (17-OHP), androstenedione, cortisol, cortisone, estradiol, follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), and testosterone. A CV-ANOVA with outlier removal and a Bayesian model were applied to derive the CVI. For estradiol, FSH and LH, only the male subgroup was included. In the indirect method, using the same analytes and groups, pairs of sequential results were extracted from the laboratory information system. The total result variation for individual pairs was determined by identifying a central gaussian distribution in the ratios of the result pairs. The CVI was then estimated by removing the effect of analytical variation.

RESULTS

The estimated CVI from the Bayesian model (μCVP(i)) in the total cohort was: 17-OHP, 23%; androstenedione, 20%; cortisol, 18%; cortisone, 11%; SHBG, 7.4%; testosterone, 16%; and for the sex hormones in men: estradiol, 14%; FSH, 8%; and LH, 26%. CVI-heterogeneity was present for most endocrine markers. Similar CVI data were estimated using the CV-ANOVA and the indirect method.

CONCLUSIONS

Similar CVI data were obtained using 2 different direct and one indirect method. The indirect approach is a low-cost alternative ensuring implementation of CVI data applicable for local conditions.

Decreased Testosterone Levels Precede a Myocardial Infarction in Both Men and Women

The potential role of the hormone testosterone in the risk for myocardial infarction is investigated in this study of middle-aged men and women compared with a large random control sample from the general population. Radioimmunoassay was used to measure testosterone levels in hair, approximately 1 month and 3 months before an ST-elevation or non-ST-elevation acute myocardial infarction. Mean testosterone levels were measured for middle-aged men and women (n = 168) with diagnosed myocardial infarction (the acute myocardial infarction [AMI] cases). As controls, n = 3,150 randomly selected subjects from the general population of similar age were measured at 1 time point. No significant difference in testosterone levels in hair was found 3 months before AMI for men and women compared with the controls. However, 1 month before AMI, the testosterone levels were decreasing (p <0.001) for both men (from 2.84 to 2.10 pg/mg) and women (from 1.43 to 1.10 pg/mg), indicating that a decrease in testosterone concentrations precedes a severe cardiac event. Conventional cardiovascular risk factors were tested as confounders but did not alter this tendency. The AMI cases were also compared with a randomly selected second control group from the general population (n = 205), for whom comparable segmental hair analyses were conducted. A tendency of some decreasing testosterone levels, also in the small control group, was only significant for men. This control group was a small sample, and there might be some natural biologic variation in testosterone levels over time. This study indicates that decreased testosterone levels may be among the pathophysiological processes preceding myocardial infarction and merits further investigation.

Overcoming challenges regarding reference materials and regulations that influence global standardization of medical laboratory testing results

BACKGROUND

Standardized results for laboratory tests are particularly important when their interpretation depends on fixed medical practice guidelines or common reference intervals. The medical laboratory community has developed a roadmap for an infrastructure to achieve standardized test results described in the International Organization for Standardization standard 17511:2020 In vitro diagnostic medical devices - Requirements for establishing metrological traceability of values assigned to calibrators, trueness control materials and human samples. Among the challenges to implementing metrological traceability are the availability of fit-for-purpose matrix-based certified reference materials (CRMs) and requirements for regulatory review that differ among countries. A workshop in December 2021 focused on these two challenges and developed recommendations for improved practices.

DISCUSSION

The participants agreed that prioritization of measurands for standardization should be based on their impact on medical decisions in a clinical pathway. Ensuring that matrix-based CRMs are globally available for more measurands will enable fit-for-purpose calibration hierarchies for more laboratory tests. Regulation of laboratory tests is important to ensure safety and effectiveness for the populations served. Because regulations are country or region specific, manufacturers must submit recalibration changes intended to standardize results for regulatory review to all areas in which a measuring system is marketed.

RECOMMENDATIONS

A standardization initiative requires collaboration and planning among all interested stakeholders. Global collaboration should be further developed for prioritization of measurands for standardization, and for coordinating the production and supply of CRMs worldwide. More uniform regulatory submission requirements are desirable when recalibration is implemented to achieve internationally standardized results.

Saliva cortisol diurnal variation and stress responses in term and preterm infants

OBJECTIVE

To determine if preterm birth is associated with adaptation of the hypothalamic-pituitary-adrenal (HPA) axis and whether HPA axis programming relates to the degree of prematurity (defined as extremely preterm birth at <28 weeks or very preterm birth at 28-32 weeks gestation).

DESIGN

This study reports findings from a prospective birth cohort. Saliva cortisol concentrations were measured prevaccination and postvaccination, and in the morning and evening, at 4 months chronological age.

SETTING

Infants born at a single Scottish hospital.

PARTICIPANTS

45 term-born, 42 very preterm and 16 extremely preterm infants.

OUTCOMES

Cortisol stress response to vaccination (postvaccination minus prevaccination cortisol concentrations), diurnal slope (log-transformed morning minus log-transformed evening cortisol values) and mean log-transformed daily cortisol.

RESULTS

Compared with infants born at term, infants born extremely preterm had a blunted cortisol response to vaccination (5.8 nmol/L vs 13.1 nmol/L, difference in means: -7.3 nmol/L, 95% CI -14.0 to -0.6) and a flattened diurnal slope (difference in geometric means: -72.9%, 95% CI -87.1 to -42.8). In contrast, the cortisol response to vaccination (difference in means -2.7 nmol/L, 95% CI -7.4 to 2.0) and diurnal slope at 4 months (difference in geometric means: -33.6%, 95% CI -62.0 to 16.0) did not differ significantly in infants born very preterm compared with infants born at term.

CONCLUSIONS

Infants born extremely preterm have blunted cortisol reactivity and a flattened diurnal slope. These patterns of HPA axis regulation are commonly seen after childhood adversity and could contribute to later metabolic and neurodevelopmental phenotypes observed in this population.

Preterm birth and infant diurnal cortisol regulation

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis adaptation is a potential mechanism linking early life exposures with later adverse health. This study tested the hypothesis that preterm birth is associated with adaptation of diurnal cortisol regulation across infancy.

METHODS

A secondary analysis was conducted of saliva cortisol measured morning, midday and evening, monthly, across infancy, as part of a birth cohort conducted in Linköping, Sweden. Diurnal cortisol regulation of infants born extremely preterm (n=24), very preterm (n=27) and at term (n=130) were compared across infancy through random coefficients regression models.

RESULTS

Compared with infants born at term, infants born extremely preterm (-17.2%, 95% CI: -30.7 to -1.2), but not very preterm (1.7%, 95% CI: -14.1 to 20.4), had a flattened diurnal slope across infancy.

CONCLUSIONS

Extremely preterm birth is associated with a flattened diurnal slope in infancy. This pattern of cortisol regulation could contribute to adverse metabolic and neurodevelopmental phenotypes observed in this population.

Hair cortisol as a biomarker of chronic stress in preadolescents: influence of school context and bullying

Bullying has been identified as the most common form of aggression and a major source of stress among children and adolescents. The main objective of this study was to analyze the association that school context in general and bullying in particular might have with hair cortisol concentration (HCC), examining the effect of executive function and sex on this association. The study included 659 11-year-old preadolescents from the cohorts of Gipuzkoa and Sabadell of the INMA (INfancia y Medio Ambiente-Children and Environment) project. We gathered information about school-related factors (bullying, school environment, problems with peers and academic performance) and executive function (risky decision-making). Hair samples were collected to measure cortisol concentrations and Structural Equation Modeling was used to examine associations between school-related factors, executive function and HCC. Results showed that being involved as a bully/victim was related to higher HCC and, higher HCC was associated with poorer executive function. This study may contribute to a better understanding of the consequences that chronic exposure to a stressful factors may have on preadolescents' health and developmental outcomes. Besides, our results are relevant for designing programs for prevention and intervention, which could modify individual physiological responses to stress and reduce the effects of stress on the health.

Diagnostic accuracy for colorectal cancer of a quantitative faecal immunochemical test in symptomatic primary care patients: a study protocol

BACKGROUND

There is increasing evidence supporting the use of faecal immunochemical tests (FIT) in patients reporting symptoms associated with colorectal cancer (CRC), but most studies until now have focused on selected subjects already referred for investigation. We therefore set out to determine the accuracy and predictive values of FIT in a primary care population.

METHOD

A prospective, multicentre, single-gated comparative diagnostic study on quantitative FIT in patients aged 40 years and above presenting in primary care with symptoms associated with CRC will be conducted. Patients representing the whole spectrum of severity of such symptoms met with in primary care will be eligible and identified by GPs. Participants will answer a short form on symptoms during the last month. They will provide two faecal samples from two separate days. Analyses will be performed within 5 days (QuikRead go®, Aidian Oy). The analytical working range is 10-200 μg Hb/g faeces. Reference test will be linked to the Swedish Colorectal Cancer Registry up to 2 years after inclusion. Accuracy, area under ROC curves, and predictive values will be calculated for one FIT compared to the highest value of two FIT and at cutoff < 10, 10-14.9, 15-19.9 and ≥ 20 μg Hb/g faeces. Subgroup analyses will be conducted for patients with anaemia and those reporting rectal bleeding. A model-based cost-effectiveness analysis based on the clinical accuracy study will be performed. Based on previous literature, we hypothesized that the sensitivity of the highest value of two FIT at cutoff 10 μg Hb/g faeces will be 95% (95% CI + / - 15%). The prevalence of CRC in the study population was estimated to be 2%, and the rate of non-responders to be 1/6. In all, 3000 patients will be invited at 30 primary care centres.

DISCUSSION

This study will generate important clinical real-life structured data on accuracy and predictive values of FIT in the most critical population for work-up of CRC, i.e. patients presenting with at times ambiguous symptoms in primary care. It will help establish the role of FIT in this large group.

TRIAL REGISTRATION

NCT05156307 . Registered on 14 December 2021-retrospectively registered.

Estimating Analytical Errors of Glomerular Filtration Rate Measurement

BACKGROUND

Few studies are available on how to optimize time points for sampling and how to estimate effects of analytical uncertainty when glomerular filtration rate (GFR) is calculated.

METHODS

We explored the underlying regression mathematics of how analytical variation of a kidney filtration marker affects 1-compartment, slope-and-intercept GFR calculations, using 2 or 3 time points following a bolus injection, and used this to examine the results from 731 routine 3-point iohexol plasma clearance measurements.

RESULTS

GFR calculations inflated analytical uncertainty if the time points were taken too late after the bolus injection and too close after each other. The uncertainty in GFR calculation was, however, the same as the analytical uncertainty if optimal time points were used. The middle of the 3 samples was of little value. The first sample should be taken as early as possible after the distribution phase. Sampling before the patient specific half-life of the kidney filtration marker resulted in an exponential error inflation whereas no error inflation was seen when sampling occurred later than 2 half-lives. Theoretical GFR uncertainty could be lowered 2.6-fold if individually optimized time points for sampling had been used in our 731 clearance measurements. Using Taylor expansions to approximate the moments of transformed random variables, the uncertainty of an individual GFR measurement could be calculated in a simple enough way to be applicable by laboratory software.

CONCLUSIONS

We provide a theoretical foundation to select patient-optimal time points that may both limit errors and allow calculation of GFR uncertainty.

Measurement uncertainty for practical use

Uncertainty is an inseparable part of all kinds of measurements performed in clinical laboratories. Accreditation standards including the ISO/IEC 17025:2017 and ISO 15189:2012 require that laboratories have routines for calculating the measurement uncertainty of reported results. Various guidelines such as CLSI EP29, Nordest 537, and ISO 20914:2019 have proposed methods for this purpose. However, due to the conceived complexity of the proposed calculation methods, these guidelines have not been generally and effectively applied in clinical laboratories. High workload and measurand heterogeneity favor a pragmatic utilitarian approach. The purpose of this paper is to describe such an approach, including its advantages and disadvantages. Measurement uncertainty should include the most influential factors affecting patients' test results. Since patients' samples for the same measurand can be analyzed in one laboratory or several laboratories using different measuring systems, the measurement uncertainty should be calculated using results obtained from analyzing the same internal quality control material if commutable or patients pooled/split samples.

[Robotic-assisted pelvic and renal surgery - an overview]

Current studies indicate that robotic-assisted surgery is not inferior to laparoscopic or open surgery regarding oncologic or functional outcomes. An exception may be uterine cervix cancer, where the survival after minimal invasive surgery might not be as good as after open surgery. There is less bleeding and need for blood transfusion after robotic-assisted surgery, and postoperative complications are similar to open or laparoscopic surgery. Robotic-assisted surgery offers ergonomic advantages compared to laparoscopic surgery. The effect of the surgical learning curve is not sufficiently studied. Presently robotic-assisted surgery is not cost-effective due to high costs of investments. The operation is more time consuming than laparoscopic or open surgery with risks of delaying and cancellation of other operations.

Standard Modifiable Cardiovascular Risk Factors Mediate the Association Between Elevated Hair Cortisol Concentrations and Coronary Artery Disease

Background

Increased cortisol exposure is a risk factor for coronary artery disease (CAD). It is not clear to what degree this risk is independent from the standard modifiable risk factors (SMuRFs) dyslipidemia, hypertension, and diabetes.

Aim

To use path analysis to test the direct and indirect association, mediated by SMuRFs, between long-term cortisol levels measured in hair cortisol concentration (HCC) and CAD.

Methods

Hair was sampled from patients admitted with acute myocardial infarction (n = 203) and a population-based sample without a diagnosis or symptoms of CAD (n = 3,134). The HCC was analyzed using radioimmunoassay and all the participants reported whether they were diagnosed with or treated for diabetes, hypertension, and hyperlipidemia. Path analysis was used to test to what degree the association between logarithmized (ln) HCC and CAD was direct or indirect, mediated by SMuRFs.

Results

Participants with CAD had elevated HCC compared to those without elevated HCC [median interquartile range (IQR): 75.2 (167.1) vs. 23.6 (35.0) pg/mg, p < 0.0001]. Higher HCC was associated with diabetes, hypertension, and hyperlipidemia, which, in turn, were associated with CAD. In path models, 80% of the association between ln(HCC) and CAD were mediated by SMuRFs, while the direct path between ln(HCC) and CAD was not statistically significant.

Conclusion

The SMuRFs diabetes, hyperlipidemia, and hypertension mediate the association between ln(HCC) and CAD. Some association between ln(HCC) and CAD did not operate via the SMuRFs considered and might have a pathway through atherosclerosis or inflammation.

Prenatal stress, anxiety and depression alter transcripts, proteins and pathways associated with immune responses at the maternal-fetal interface†

During pregnancy, the immune system is modified to allow developmental developmental tolerance of the semi-allogeneic fetus and placenta to term. Pregnant women suffering from stress, anxiety and depression show dysfunctions of their immune system that may be responsible for fetal and/or newborn disorders, provided that provided that placental gene regulation is compromised. The present study explored the effects of maternal chronic self-perceived stress, anxiety and depression during pregnancy on the expression of immune related-genes and pathways in term placenta. Pregnancies were clinically monitored with the Beck's Anxiety Inventory (BAI) and Edinburgh Postnatal Depression Scale (EPDS). A cutoff threshold for BAI/EPDS of 10 divided patients into two groups: Index group (≥10, n = 11) and a Control group (<10, n = 11), whose placentae were sampled at delivery. The placental samples were subjected to RNA-Sequencing, demonstrating that stress, anxiety and depression during pregnancy induced a major downregulation of placental transcripts related to immune processes such as T-cell regulation, interleukin and cytokine signaling or innate immune responses. Expression differences of main immune related genes such as CD46, CD15, CD8α & β ILR7α and CCR4 among others, were found in the index group (P < 0.05). Moreover, the key immune-like pathway involved in humoral and cellular immunity named "Primary immunodeficiency" was significantly downregulated in the index group compared to controls. Our results show that mechanisms ruling immune system functions are compromised at the maternal-fetal interface following self-perceived depressive symptoms and anxiety during pregnancy. These findings may help unveil mechanisms ruling the impact of maternal psychiatric symptoms and lead to new prevention/intervention strategies in complicated pregnancies.

Associations of hair cortisol concentrations with paediatric appendicitis

The pathogenesis of paediatric appendicitis is still an enigma. In recent years, it has become more evident that our inherent immunological responses affect the trajectory of the disease course. Long-term stress has an impact on our immune system; however, it is practically and ethically challenging to prospectively track blood measurements of cortisol-levels in asymptomatic children should an acute appendicitis episode develop. The aim of this case–control study was therefore to evaluate the effect of increased stress measured as historical imprints in hair (hair cortisol concentrations [HCC]), on the risk of developing appendicitis and complicated appendicitis. 51 children (aged < 15 years) with appendicitis (34 with complicated appendicitis), were compared to 86 healthy controls. HCC reflecting the activity of the HPA-axis 0–3 and 4–6 months prior to sampling was evaluated and compared between groups as well as between the two measurements of each study subject. In the univariate analysis with both cases and controls, an increase in HCC between the measurement timepoints was associated with a substantial increase in risk of appendicitis (OR 7.52 [95% CI 2.49–22.67], p = 0.001). This increased risk remained in the multivariate analysis after adjustment for age, sex and season (aOR OR 10.76 [95%CI 2.50–46.28], p  = 0.001). When comparing the cases of uncomplicated and complicated appendicitis through a multivariate analysis, adjusted for age and sex, the children with an increased HCC prior to appendicitis had a substantial and statistically significant increase in risk of complicated appendicitis (aOR 7.86 [95% CI 1.20–51.63], p = 0.03). Biological stress, measured as an increase in HCC, seems to be associated with an increased risk of paediatric appendicitis and a more complicated disease course.

Disorganization and degeneration of liver sympathetic innervations in nonalcoholic fatty liver disease revealed by 3D imaging

Hepatic nerves have a complex role in synchronizing liver metabolism. Here, we used three-dimensional (3D) immunoimaging to explore the integrity of the hepatic nervous system in experimental and human nonalcoholic fatty liver disease (NAFLD). We demonstrate parallel signs of mild degeneration and axonal sprouting of sympathetic innervations in early stages of experimental NAFLD and a collapse of sympathetic arborization in steatohepatitis. Human fatty livers display a similar pattern of sympathetic nerve degeneration, correlating with the severity of NAFLD pathology. We show that chronic sympathetic hyperexcitation is a key factor in the axonal degeneration, here genetically phenocopied in mice deficient of the Rac-1 activator Vav3. In experimental steatohepatitis, 3D imaging reveals a severe portal vein contraction, spatially correlated with the extension of the remaining nerves around the portal vein, enlightening a potential intrahepatic neuronal mechanism of portal hypertension. These fundamental alterations in liver innervation and vasculature uncover previously unidentified neuronal components in NAFLD pathomechanisms.

Stress and perceived health among primary care visitors in two corners of Europe: Scandinavia and Greece

BACKGROUND

The global financial crisis emerging in 2008 struck Greece especially hard, whereas Scandinavian countries were less affected. This has created a unique opportunity to study the long-term effect of community stress on populations. Increasing frequencies of mental health issues and poorer perceived health among the Greek population have been reported. The physiological marker of long-term stress, cortisol in hair, is applied in this study together with measures of perceived health and stress, depression and anxiety. Our aim was to study self-reported and physiological stress, perceived health, including mental health, in the general population of Greece compared to Scandinavia, in order to assess long-term effects of the economic crisis on these parameters.

METHODS

A cross-sectional comparative study of adult (18-65 years) Primary Health Care visitors from semi-rural areas in Greece (n = 84) and Scandinavia (n = 140). Data collection was performed in 2012, and encompassed a questionnaire with a variety of health and stress indicators as well as hair samples for analyzes of cortisol levels.

RESULTS

The Greek sample reported significantly poorer overall health (p < 0.0001) than the Scandinavians and a significantly higher perceived stress (p < 0.0001). The Greeks were also less hopeful of the future (p < 0.0001), and to a larger extent fulfilled the HAD criteria for depression (p < 0.0001) and anxiety (p = 0.002). The strongest predictors explaining ill health in logistic regressions were being Greek (p = 0.001) and feeling hopeless about the future p = 0.001, OR = 6.00 (CI 2.10-14.88). Strong predictors in logistic regressions for high perceived stress were anxiety: high (p < 0.0001) and medium (p = 0.0001), as well as medium depression (p = 0.02).

CONCLUSIONS

Greek adult Primary Health Care visitors perceived their health more negatively than the Scandinavians, including a higher presence of depression, anxiety, and a lower hope for the future. The Greeks also reported higher perceived stress, but this was not reflected in higher cortisol levels. The findings presented here, identify possible adverse long-term effects of the economic crisis in the examined Greek population that are not seen in the Scandinavian cohort. These differences may also be interpreted against the background of socio-cultural differences in the northern and south-eastern corners of Europe.

[Follow-up study of very low birthweight children in Sweden at the age of 27-28]

Studies show that very low birthweight can be an important risk factor for mental problems, disturbed fertility and neuroendocrine dysregulation. In a regional long-term study 56 of 86 adult individuals 27 to 28 years of age with a very low birthweight were compared with normal birthweight controls. Analyses of self-reported mental health, socio-demographic factors, sex hormone levels, and hair cortisol levels showed no significant differences between the groups. However, in order to analyse subgroups with different risk factors from the newborn period or children with a variety of social background factors, larger patient groups are needed.

Parity-related variation in cortisol concentrations in hair during pregnancy

Objective

To investigate hair cortisol concentrations (HCC) monthly in pregnant women and to explore the effect of parity.

Design

Prospective cohort study from gestational week (GW) 26, at childbirth and postpartum.

Setting

An antenatal care clinic in southeast Sweden.

Sample

390 pregnant women.

Methods

Cortisol was measured using radioimmunoassay in methanol extracts of ground hair samples.

Main outcome measures

Hair cortisol concentrations.

Results

Both primi‐ and multiparae exhibited an increase in HCC throughout pregnancy. Primiparae had significantly higher HCC in the latter part of the last trimester compared with multiparae (1 month P = 0.003, 2 months P = 0.038). The use of psychotropic medication in the first trimester correlated to HCC postpartum (P < 0.001). HCC in GW 14–17 was associated with HCC in GW 18–21 (primiparae and multiparae, P < 0.001), GW 22–25 (primiparae P = 0.036, multiparae P = 0.033), and 2 months postpartum (primiparae P = 0.049). HCC in GW 18–21 was associated with GW 22–25 in both primiparae (P < 0.001) and multiparae (P < 0.001) as well as 2 months prior to childbirth among primiparae (<0.037). In general, all estimates of HCC in pregnancy and postpartum showed a significant association between HCC for a specific month and the HCC in the previous month (all P < 0.001), except for the association of HCC among primiparae in GW 22–25 and 3 months prior to childbirth.

Conclusions

Increased cortisol concentrations in hair were observed during pregnancy, which decreased 3 months prior to childbirth in multiparae. The results indicate a quicker suppression of the hypothalamic CRH (corticotropin‐releasing hormone) production by placenta CRH in multiparous women.

Tweetable abstract

Multiparae have a quicker suppression of hypothalamic CRH production by placenta CRH during pregnancy compared to primiparae.

Multiparae have a quicker suppression of hypothalamic CRH production by placenta CRH during pregnancy compared with primiparae.

Management of Diastasis of the Rectus Abdominis Muscles: Recommendations for Swedish National Guidelines

Background:

Diastasis of the rectus abdominis muscle is a common condition. There are no generally accepted criteria for diagnosis or treatment of diastasis of the rectus abdominis muscle, which causes uncertainty for the patient and healthcare providers alike.

Methods:

The consensus document was created by a group of Swedish surgeons and based on a structured literature review and practical experience.

Results:

The proposed criteria for diagnosis and treatment of diastasis of the rectus abdominis muscle are as follows: (1) Diastasis diagnosed at clinical examination using a caliper or ruler for measurement. Diagnostic imaging by ultrasound or other imaging modality, should be performed when concurrent umbilical or epigastric hernia or other cause of the patient’s symptoms cannot be excluded. (2) Physiotherapy is the firsthand treatment for diastasis of the rectus abdominis muscle. Surgery should only be considered in diastasis of the rectus abdominis muscle patients with functional impairment, and not until the patient has undergone a standardized 6-month abdominal core training program. (3) The largest width of the diastasis should be at least 5 cm before surgical treatment is considered. In case of pronounced abdominal bulging or concomitant ventral hernia, surgery may be considered in patients with a smaller diastasis. (4) When surgery is undertaken, at least 2 years should have elapsed since last childbirth and future pregnancy should not be planned. (5) Plication of the linea alba is the firsthand surgical technique. Other techniques may be used but have not been found superior.

Discussion:

The level of evidence behind these statements varies, but they are intended to lay down a standard strategy for treatment of diastasis of the rectus abdominis muscle and to enable uniformity of management.

Self-reported mental health and cortisol activity at 27-28 years of age in individuals born with very low birthweight

Aim

To assess mental health outcomes of very low birthweight (VLBW, <1500 g) subjects to adulthood and to examine salivary cortisol and hair cortisol levels and their relation to birth characteristics and mental health.

Methods

A Swedish regional cohort of 56 VLBW subjects and 55 full‐term controls were assessed at the ages 27‐28 with adult self‐reported scales and the mean of 2 days diurnal salivary cortisol and hair cortisol. The cohorts had been assessed at 15 years of age with youth self‐reported scales.

Results

There were no differences between the groups in youth self‐reported scales and adult self‐reported scores. The 24 participating VLBW girls scored lower on youth self‐reported scales externalising and total problem scores than the control girls. In adulthood, the 21 participating VLBW women had significantly higher morning concentrations of salivary cortisol than control women, P = .014. No significant associations were found between cortisol concentrations and adult self‐reported scales internalising, externalising and total scores.

Conclusion

Self‐reported mental health in VLBW subjects was comparable with normal birthweight controls indicating a satisfying transition from adolescence to adulthood. VLBW females had higher morning salivary cortisol concentrations, suggesting a gender difference. We found no correlations between cortisol and mental health.

Pre-traumatic conditions can influence cortisol levels before and after a brain injury

OBJECTIVE

Satisfactory anabolic reactions, including the activation of the hypothalamic-pituitary-adrenal (HPA) axis, are essential following severe traumatic brain injury (TBI) and aneurysmal subarachnoid hemorrhage (SAH). Many factors may influence this activation. This study aimed to investigate whether individuals who reported chronic diseases, psychosocial afflictions, or stressful events before a severe brain injury display a different pattern regarding cortisol levels retrospectively and up to three months compared with those who did not report stressful experiences.

MATERIALS AND METHODS

Fifty-five patients aged 16-68 years who were admitted to the neurointensive care unit (NICU) were included. Hair cortisol measurements offer a unique opportunity to monitor cortisol levels retrospectively and after the trauma. Hair strands were collected as soon as possible after admission to the NICU and every month until three months after the injury/insult. The participants/relatives were asked about stressful events, psychosocial afflictions and recent and chronic diseases.

RESULTS

The group who reported chronic diseases and/or stressful events before the brain injury had more than twice as high median hair cortisol levels before the brain injury compared with those who did not report stress, but the difference was not statistically significant (P = .12). Those who reported stress before the brain injury had statistically significantly lower hair cortisol values after the brain injury and they remained until three months after the injury.

CONCLUSIONS

Stressful events and/or chronic disease before brain injury might affect mobilization of adequate stress reactions following the trauma. However, the large variability in cortisol levels in these patients does not allow firm conclusions and more studies are needed.

Measurement repeatability profiles of eight frequently requested measurands in clinical chemistry determined by duplicate measurements of patient samples

Measurement uncertainties in clinical chemistry are commonly regarded as heteroscedastic - having a constant relative standard deviation irrespective of the concentration of the measurand. The uncertainty is usually determined at two concentrations using stabilized control materials and assumed to represent the analytical goal. The purpose of the present study was to use duplicates of unselected patient samples to calculate the absolute and relative repeatability component of the intra-laboratory measurement uncertainty from duplicates, using the Dahlberg formula and analysis of variance components. Estimates were made at five different concentration intervals of ALT, AST, Calcium, Cholesterol, Creatinine, CRP, Triglycerides and TSH covering the entire concentration interval of the patient cohort. This partioning allows detailing their repeatability profiles. The calculations of the profiles were based on randomly selected results from sets of duplicates ranging from 12,000 to 65,000 pairs. The repeatability of the measurands showed substantial variability within the measuring interval. Therefore, characterizing imprecision profiles as purely homo- or heteroscedastic or by a single number may not be optimal for the intended use. The present data make a case for nuancing the evaluation of analytical goals and minimal differences of measurement results by establishing uncertainty profiles under repeatability conditions, using natural patient samples.

Repeatability imprecision from analysis of duplicates of patient samples and control materials

Measurement imprecision is usually calculated from measurement results of the same stabilized control material(s) obtained over time, and is therefore, principally, only valid at the concentration(s) of the selected control material(s). The resulting uncertainty has been obtained under reproducibility conditions and corresponds to the conventional analytical goals. Furthermore, the commutability of the control materials used determines whether the imprecision calculated from the control materials reflects the imprecision of measuring patient samples. Imprecision estimated by measurements of patient samples uses fully commutable samples, freely available in the laboratories. It is commonly performed by calculating the results of routine patient samples measured twice each. Since the duplicates are usually analysed throughout the entire concentration interval of the patient samples processed in the laboratory, the result will be a weighted average of the repeatability imprecision measured in the chosen measurement intervals or throughout the entire interval of concentrations encountered in patient care. In contrast, the uncertainty derived from many measurements of control materials over periods of weeks is usually made under reproducibility conditions. Consequently, the repeatability and reproducibility imprecision play different roles in the inference of results in clinical medicine. The purpose of the present review is to detail the properties of the imprecision calculated by duplicates of natural samples, to explain how it differs from imprecision calculated from single concentrations of control materials, and to elucidate what precautions need to be taken in case of bias, e.g. due to carry-over effects.

An experimental study of methods for the analysis of variance components in the inference of laboratory information

Measurement uncertainty (MU) can be estimated and calculated by different procedures, representing different aspects and intended use. It is appropriate to distinguish between uncertainty determined under repeatability and reproducibility conditions, and to distinguish causes of variation using analysis of variance components. The intra-laboratory MU is frequently determined by repeated measurements of control material(s) of one or several concentrations during a prolonged period of time. We demonstrate, based on experimental results, how such results can be used to identify the repeatability, 'pure' reproducibility and intra-laboratory variance as the sum of the two. Native patient material was used to establish repeatability using the Dahlberg formula for random differences between measurements and an expanded Dahlberg formula if a non-random difference, e.g. bias, was expected. Repeatability and reproducibility have different clinical relevance in intensive care compared to monitoring treatment of chronic diseases, comparison with reference intervals or screening.

Male Testosterone Does Not Adapt to the Partner's Menstrual Cycle

BACKGROUND

It has not yet been established whether men in heterosexual relationships adapt their hormone levels to their female partner's menstrual cycle to allocate reproductive resources to the period when the female is actually fertile.

AIM

This prospective observational study tested the hypothesis that some males have peaks in testosterone or acne (a possible biomarker for androgen activity) near their partners' ovulation, whereas other males display the opposite pattern.

METHODS

48 couples supplied menstrual cycle data, male salivary samples, and a protocol of daily activities for 120 days. Daily saliva samples were analyzed for testosterone concentrations by enzyme-linked immunosorbent assay. The main hypothesis was tested by analyzing whether each individual male's testosterone/acne response to ovulation (either an increase or a decrease in comparison to the individual's average levels) was stable over time. To do this, we analyzed the Spearman correlation between individually normalized periovulatory testosterone and acne during the first half of the study versus the second half of the study.

OUTCOMES

Correlation between each male individual's periovulatory testosterone and acne patterns during the first half of the study versus the second half of the study.

RESULTS

No predictability in the male individuals' testosterone (Spearman's rho = -0.018, P = .905) or acne (Spearman's rho = -0.036, P = .862) levels during ovulation was found.

CLINICAL TRANSLATION

The study being "negative," there is no obvious translational potential in the results.

STRENGTHS AND LIMITATIONS

The main strength of this study lies in the excellent compliance of the study participants and the large number of sampling timepoints over several menstrual cycles, thereby allowing each male individual to be his own control subject. A limitation is that samples were only obtained in the morning; however, including later timepoints would have introduced a number of confounders and would also have hampered the study's feasibility.

CONCLUSIONS

The current results strongly indicate that male morning testosterone levels neither increase nor decrease in response to the partner's ovulation. This discordance to previous laboratory studies could indicate either that (i) the phenomenon of hormonal adaptation of men to women does not exist and earlier experimental studies should be questioned, (ii) that the phenomenon is short-lived/acute and wanes if the exposure is sustained, or (iii) that the male testosterone response may be directed toward other women than the partner. Ström JO, Ingberg E, Slezak JK, et al. Male Testosterone Does Not Adapt to the Partner's Menstrual Cycle. J Sex Med 2018;15:1103-1110.