Identification of clinical biomarkers for pre-analytical quality control of blood samples

Optimal conditions for sampling of blood cytokine tests using AimPlex flow cytometry

OBJECTIVES

Quantification of cytokine is indispensable to elucidate the mechanism of immune regulation at the molecular level, thereby contributing to the diagnosis and treatment of several diseases. Here, we aimed to determine the effect of detection method and storage conditions of specimens on the quantification of cytokine levels.

METHODS

We used four vacuum blood collection tubes containing EDTA, heparin, clot activator, gel and compared the changes in the expression levels of 14 cytokines in serum and plasma samples at different temperatures and durations of storage using AimPlex flow cytometry-based immunoassay. In addition, we analyzed the changes in cytokine sensitivity and its clinical relevance after re-establishing cutoff values compared to those set by the manufacturer.

RESULTS

The cytokine levels were higher in the plasma of healthy individuals than in their serum. Reliable values for most cytokines were obtained in gel-serum samples, centrifuged within 4 h of collection, and stored at -20 °C for up to 24 h. We measured cytokine levels in 1064 healthy controls using tubes containing separation gel to recalculate their cutoff values and observed changes in cytokine positivity in patients. IL-6 positivity increased from approximately 90% to 95% in patients with sepsis and severe pneumonia. Similarly, IL-8 increased from 48.7% and 41.7% to 79.5% and 63.9% in patients with sepsis and severe pneumonia.

CONCLUSIONS

Cytokines are more stable in gel-serum than in plasma or clot activator-serum, and they should be quantified within 4 h or within 24 h if the sample is centrifuged and stored at -20 °C.

Recent Technologies towards Diagnostic and Therapeutic Applications of Circulating Nucleic Acids in Colorectal Cancers

Liquid biopsy has emerged as a promising noninvasive approach for colorectal cancer (CRC) management. This review focuses on technologies detecting circulating nucleic acids, specifically circulating tumor DNA (ctDNA) and circulating RNA (cfRNA), as CRC biomarkers. Recent advancements in molecular technologies have enabled sensitive and specific detection of tumor-derived genetic material in bodily fluids. These include quantitative real-time PCR, digital PCR, next-generation sequencing (NGS), and emerging nanotechnology-based methods. For ctDNA analysis, techniques such as BEAMing and droplet digital PCR offer high sensitivity in detecting rare mutant alleles, while NGS approaches provide comprehensive genomic profiling. cfRNA detection primarily utilizes qRT-PCR arrays, microarray platforms, and RNA sequencing for profiling circulating microRNAs and discovering novel RNA biomarkers. These technologies show potential in early CRC detection, treatment response monitoring, minimal residual disease assessment, and tumor evolution tracking. However, challenges remain in standardizing procedures, optimizing detection limits, and establishing clinical utility across disease stages. This review summarizes current circulating nucleic acid detection technologies, their CRC applications, and discusses future directions for clinical implementation.

Pre-analytical stability of the CEA, CYFRA 21.1, NSE, CA125 and HE4 tumor markers

BACKGROUND

For lung cancer, circulating tumor markers (TM) are available to guide clinical treatment decisions. To ensure adequate accuracy, pre-analytical instabilities need to be known and addressed in the pre-analytical laboratory protocols.

OBJECTIVE

This study investigates the pre-analytical stability of CA125, CEA, CYFRA 21.1, HE4 and NSE for the following pre-analytical variables and procedures; i) whole blood stability, ii) serum freeze-thaw cycles, iii) electric vibration mixing and iv) serum storage at different temperatures.

METHODS

Left-over patient samples were used and for every investigated variable six patient samples were used and analysed in duplicate. Acceptance criteria were based on analytical performance specifications based on biological variation and significant differences with baseline.

RESULTS

Whole blood was stable for at least 6 hours for all TM except for NSE. Two freeze-thaw cycles were acceptable for all TM except CYFRA 21.1. Electric vibration mixing was allowed for all TM except for CYFRA 21.1. Serum stability at 4°C was 7 days for CEA, CA125, CYFRA 21.1 and HE4 and 4 hours for NSE.

CONCLUSIONS

Critical pre-analytical processing step conditions were identified that, if not taken into account, will result in reporting of erroneous TM results.

Detecting Pre-Analytically Delayed Blood Samples for Laboratory Diagnostics Using Raman Spectroscopy

In this proof-of-principle study, we systematically studied the potential of Raman spectroscopy for detecting pre-analytical delays in blood serum samples. Spectra from 330 samples from a liver cirrhosis cohort were acquired over the course of eight days, stored one day at room temperature, and stored subsequently at 4 °C. The spectra were then used to train Convolutional Neural Networks (CNN) to predict the delay to sample examination. We achieved 90% accuracy for binary classification of the serum samples in the groups "without delay" versus "delayed". Spectra recorded on the first day could be distinguished clearly from all subsequent measurements. Distinguishing between spectra taken in the range from the second to the last day seems to be possible as well, but currently, with an accuracy of approximately 70% only. Importantly, filtering out the fluorescent background significantly reduces the precision of detection.

Forensic biomarkers of lethal traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and its accurate diagnosis is an important concern of daily forensic practice. However, it can be challenging to diagnose TBI in cases where macroscopic signs of the traumatic head impact are lacking and little is known about the circumstances of death. In recent years, several post-mortem studies investigated the possible use of biomarkers for providing objective evidence for TBIs as the cause of death or to estimate the survival time and time since death of the deceased. This work systematically reviewed the available scientific literature on TBI-related biomarkers to be used for forensic purposes. Post-mortem TBI-related biomarkers are an emerging and promising resource to provide objective evidence for cause of death determinations as well as survival time and potentially even time since death estimations. This literature review of forensically used TBI-biomarkers revealed that current markers have low specificity for TBIs and only provide limited information with regards to survival time estimations and time since death estimations. Overall, TBI fatality-related biomarkers are largely unexplored in compartments that are easily accessible during autopsies such as urine and vitreous humor. Future research on forensic biomarkers requires a strict distinction of TBI fatalities from control groups, sufficient sample sizes, combinations of currently established biomarkers, and novel approaches such as metabolomics and mi-RNAs.

Stability of serum biochemical markers during standard long-term storage and with a single thawing

Aim. To study the effect of standard serum long-term storage at -70О C and with a single thawing on the biochemical markers by comparing the results of studies carried out in 2013-2014 and 2020.

Material and methods. The material was the blood serum of participants in the ESSE-RF study, which was stored in a specialized biobank from 2013-2014 at -70О C either continuously (n=149) or with a single thawing (n=20). Initially and in 2020, the quantitative determination of serum biochemical parameters was carried out using same equipment and standard techniques.

Results. Long-term storage at -70О C led to mild, but significant changes in almost all analyzed parameters: low density lipoprotein cholesterol (LDL-C) and apolipoprotein A1 levels decreased; levels of highdensity lipoprotein cholesterol (HDL-C), triglycerides, apolipoprotein B, glucose, and high-sensitivity C-reactive protein increased. Insulin and thyroid-stimulating hormone levels did not change during storage. The revealed strong positive relationships between the initial concentrations and those measured in 2020 in samples that were stored continuously indicate the relevance of such storage. In samples with single thawing, changes in most parameters were more pronounced.

Conclusion. The results of a prospective cohort study aimed at studying the stability of human serum samples during storage indicate the validity of long-term storage at -70О C without thawing. Freeze-thawing cycle of samples (even once) is unacceptable, since it leads to a pronounced LDL-C decrease. Given the fact that it is the LDL-C levels that is the target of lipid-lowering therapy, continuous low-temperature (not >-70О C) storage of blood serum samples is recommended.

Relevant criteria for the selection of cryotubes. Experiences from the German National Cohort

Background

The storage of different biomaterials over long time periods is one of the main requirements of biobanking ensuring that modifications in the composition or any other change of the biomaterials have to be avoided. In the German National Cohort samples from around 200,000 participants are processed and stored long term.

Methods

A tender for cryotubes and racks was performed in 2013 setting up several characteristics that were judged against each other. Tubes and racks were evaluated regarding the performance and handling in connection with the main biorepository. With a 5-year experience using the selected tubes we are able to reflect some of the criteria of the tender.

Results

At the end of the decision, the former company FluidX, in the meantime taken over from Brooks (Brooks Life Sciences, Manchester, UK), received the order. The experience with the external testing of the tube was useful.

Conclusions

Overall, the experience with the cryotubes is good and their mechanical handling at the different sites is routine in the meantime. There are some aspects that we recommend for future tenders. Further research is necessary to learn more about the cryotubes and the labware in general in the field of biobanking to store our samples as safely as possible.

Quality Assessment of the Preanalytical Workflow in Liquid Biobanking: Taurine as a Serum-Specific Quality Indicator for Preanalytical Process Variations

The scientific impact of translational biomedical research largely depends on the availability of high-quality biomaterials. However, evidence-based and robust quality indicators (QIs) covering the most relevant preanalytical variations are still lacking. The aim of this study was to identify and validate a QI suitable for assessing time-to-centrifugation (TTC) delays in human liquid biospecimens originating from both healthy and diseased individuals. Serum and plasma samples with varying TTCs were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in a pilot cohort of healthy individuals to identify a suitable QI candidate. Taurine (TAU), as a TTC QI candidate, was validated in healthy individuals and patients with rheumatologic and cardiologic diseases, considering the (1) preanalytical handling temperature, (2) platelet count, and (3) postcentrifugation delay. For discrimination of high TTC (TTC >60 minutes) from low TTC serum specimens, a probability calculation tool was developed (Triple-T-cutoff-model). TTC-dependent changes in healthy individuals were observed for amino acids, particularly TAU. Validation of the TAU levels in an independent cohort of healthy individuals revealed a time-dependent increase in serum, but not in plasma, for a TTC delay of 30-240 minutes. TAU increases were dependent on the handling temperature and platelet count and volume. By contrast, no changes in TAU concentrations were observed for additional postcentrifugation delays. Validation of TAU and the Triple-T-cutoff-model, in rheumatologic/cardiologic patient collectives, allowed the discrimination of samples with TTC ≤60 min/>60 min with estimated AUROC (area under the receiver operating characteristic curve) values of 89% [78%-100%]/86% [71%-100%] and 91% [79%-100%]/84% [68%-100%], respectively. Considering the preanalytical handling temperature and platelet count and volume, TAU and the Triple-T-cutoff-model represent reliable QIs for TTC >60 minutes in serum samples from healthy individuals and selected rheumatologic/cardiologic patients. However, further studies in larger patient collectives with various diseases are needed to assess the robustness and potential of the QIs presented in this article as biobanking quality assurance/quality control tools to support high-quality biomedical research.

Laboratory sample stability. Is it possible to define a consensus stability function? An example of five blood magnitudes

Background:

The stability limit of an analyte in a biological sample can be defined as the time required until a measured property acquires a bias higher than a defined specification. Many studies assessing stability and presenting recommendations of stability limits are available, but differences among them are frequent. The aim of this study was to classify and to grade a set of bibliographic studies on the stability of five common blood measurands and subsequently generate a consensus stability function.

Methods:

First, a bibliographic search was made for stability studies for five analytes in blood: alanine aminotransferase (ALT), glucose, phosphorus, potassium and prostate specific antigen (PSA). The quality of every study was evaluated using an in-house grading tool. Second, the different conditions of stability were uniformly defined and the percent deviation (PD%) over time for each analyte and condition were scattered while unifying studies with similar conditions.

Results:

From the 37 articles considered as valid, up to 130 experiments were evaluated and 629 PD% data were included (106 for ALT, 180 for glucose, 113 for phosphorus, 145 for potassium and 85 for PSA). Consensus stability equations were established for glucose, potassium, phosphorus and PSA, but not for ALT.

Conclusions:

Time is the main variable affecting stability in medical laboratory samples. Bibliographic studies differ in recommedations of stability limits mainly because of different specifications for maximum allowable error. Definition of a consensus stability function in specific conditions can help laboratories define stability limits using their own quality specifications.

Proteomics and Lipidomics in Inflammatory Bowel Disease Research: From Mechanistic Insights to Biomarker Identification

Inflammatory bowel disease (IBD) represents a group of progressive disorders characterized by recurrent chronic inflammation of the gut. Ulcerative colitis and Crohn's disease are the major manifestations of IBD. While our understanding of IBD has progressed in recent years, its etiology is far from being fully understood, resulting in suboptimal treatment options. Complementing other biological endpoints, bioanalytical "omics" methods that quantify many biomolecules simultaneously have great potential in the dissection of the complex pathogenesis of IBD. In this review, we focus on the rapidly evolving proteomics and lipidomics technologies and their broad applicability to IBD studies; these range from investigations of immune-regulatory mechanisms and biomarker discovery to studies dissecting host⁻microbiome interactions and the role of intestinal epithelial cells. Future studies can leverage recent advances, including improved analytical methodologies, additional relevant sample types, and integrative multi-omics analyses. Proteomics and lipidomics could effectively accelerate the development of novel targeted treatments and the discovery of complementary biomarkers, enabling continuous monitoring of the treatment response of individual patients; this may allow further refinement of treatment and, ultimately, facilitate a personalized medicine approach to IBD.

Effect of Repeated Freeze-Thaw on Serum Biomarkers Associated with Eye Disease

Background

Serum biomarkers are associated with eye diseases, which results in the need for cryopreservation of serum samples. However, the effect on serum biomarker levels of repeatedly freezing and thawing remains poorly understood. The aim of this study was to evaluate the effects of repeated freeze-thaw on the serum levels of the protein, complement C3c (C3c), the micromolecule, uric acid (UA), and the enzyme, angiotensin-converting enzyme (ACE).

Material/Methods

Serum samples were obtained from 50 patients who attended an ophthalmic outpatient department. Following baseline measurements, the serum samples from each subject were divided into aliquots and stored at −80°C for further analysis, following between one to six freeze-thaw cycles. The serum levels of C3c, UA, and ACE were measured immediately after the stored serum samples were thawed.

Results

The serum level of C3c was significantly changed after the first freeze-thaw cycle (p<0.05), and a significant alteration in serum ACE levels occurred after the third freeze-thaw cycle (p<0.05). The serum UA level remained unchanged after all freeze-thaw cycles. Repeated freeze-thaw cycles significantly increased the serum levels of C3c and decreased the serum levels of ACE. The serum levels of C3c, UA, and ACE, respectively were significantly correlated (p<0.001), while the correlation coefficient for C3c and UA were improved when compared with ACE.

Conclusions

Repeated freeze-thaw can have variable effects on the serum levels of biomarkers, C3c, UA and ACE, which supports the need for quality control of cryopreserved serum for biomarker evaluation.

Understanding preanalytical variables and their effects on clinical biomarkers of oncology and immunotherapy

Identifying a suitable course of immunotherapy treatment for a given patient as well as monitoring treatment response is heavily reliant on biomarkers detected and quantified in blood and tissue biospecimens. Suboptimal or variable biospecimen collection, processing, and storage practices have the potential to alter clinically relevant biomarkers, including those used in cancer immunotherapy. In the present review, we summarize effects reported for immunologically relevant biomarkers and highlight preanalytical factors associated with specific analytical platforms and assays used to predict and gauge immunotherapy response. Given that many of the effects introduced by preanalytical variability are gene-, transcript-, and protein-specific, biospecimen practices should be standardized and validated for each biomarker and assay to ensure accurate results and facilitate clinical implementation of newly identified immunotherapy approaches.

Blood Sampling and Preparation Procedures for Proteomic Biomarker Studies of Psychiatric Disorders

A major challenge in proteomic biomarker discovery and validation for psychiatric diseases is the inherent biological complexity underlying these conditions. There are also many technical issues which hinder this process such as the lack of standardization in sampling, processing and storage of bio-samples in preclinical and clinical settings. This chapter describes a reproducible procedure for sampling blood serum and plasma that is specifically designed for maximizing data quality output in two-dimensional gel electrophoresis, multiplex immunoassay and mass spectrometry profiling studies.

Blood Bio-Sampling Procedures for Multiplex Biomarkers Studies

A major challenge in single or panel of biomarker discovery and validation is the inherent biological complexity underlying disease heterogeneity and inconsistent responses to treatment. Moreover, the lack of standardization in the sampling, processing, and storage of biological fluids such as plasma and serum disrupts the discovery and validation of blood-based biomarker tests in preclinical and clinical settings. This chapter presents a reproducible sample collection and handling procedure that aims to enhance analyte stability and ensure compatibility with the corresponding multiplex biomarker profiling platforms. The importance of defining bio-sample acquisition and processing, study design, and profiling platform guidelines for blood-based biomarker measurements is paramount for the success of personalized healthcare strategy and development of companion diagnostics.

Stability of cytokines, chemokines and soluble activation markers in unprocessed blood stored under different conditions

BACKGROUND

Biomarkers such as cytokines, chemokines, and soluble activation markers can be unstable when processing of blood is delayed. The stability of various biomarkers in serum and plasma was investigated when unprocessed blood samples were stored for up to 24h at room and refrigerator temperature.

METHODS

Blood was collected from 16 healthy volunteers. Unprocessed serum, EDTA and heparinized blood was stored at room (20-25°C) and refrigerator temperature (4-8°C) for 0.5, 2, 4, 6, 8, and 24h after collection before centrifugation and separation of serum and plasma. Samples were batch tested for various biomarkers using commercially available immunoassays. Statistically significant changes were determined using the generalized estimating equation.

RESULTS

IFN-γ, sIL-2Rα, sTNF-RII and β2-microglobulin were stable in unprocessed serum, EDTA and heparinized blood samples stored at either room or refrigerator temperature for up to 24h. IL-6, TNF-α, MIP-1β and RANTES were unstable in heparinized blood at room temperature; TNF-α, and MIP-1β were unstable in unprocessed serum at room temperature; IL-12 was unstable in unprocessed serum at refrigerator temperature; and neopterin was unstable in unprocessed EDTA blood at room temperature. IL-1ra was stable only in unprocessed serum at room temperature.

CONCLUSION

All the biomarkers studied, with the exception of IL-1ra, were stable in unprocessed EDTA blood stored at refrigerator temperature for 24h. This indicates that blood for these biomarkers should be collected in EDTA and if delays in processing are anticipated the unseparated blood should be stored at refrigerator temperature until processing.

Impact of Whole-Blood Processing Conditions on Plasma and Serum Concentrations of Cytokines

Pre-analytical variations in plasma and serum samples can occur because of variability in whole-blood processing procedures. The aim of this study was to determine the impact of delayed separation of whole blood on the plasma and serum concentrations of cytokines. The concentrations of 16 cytokines were measured in plasma and serum samples when the centrifugation of whole blood at room temperature was delayed for 4, 6, 24, or 48 h, and the values were compared with those observed after separation within 2 h of whole-blood collection. Receiver operating characteristic (ROC) curve analysis was also performed for cytokines to determine whether cytokine levels in plasma and serum samples can be used to assess delayed separation of whole blood. Plasma concentrations of interleukin (IL)-1β, granulocyte-macrophage colony-stimulating factor (GM-CSF), and soluble CD40 ligand (sCD40L) and serum concentrations of IL-1β, IL-6, IL-8, macrophage inflammatory protein-1α (MIP-1α), and MIP-1β increased significantly (>2-fold) when separation was delayed at room temperature for 24 h. The concentrations of 6 of these cytokines (all except serum IL-1β and IL-6) demonstrated high diagnostic performance (area under the ROC curve >0.8) for delayed separation of whole blood. Furthermore, these cytokine concentrations typically exhibited high sensitivity and specificity at each optimal cutoff point. Conversely, IL-17A was stable in both plasma and serum samples, even when whole-blood centrifugation was delayed at room temperature for 48 h. This study shows that certain cytokines (IL-1β, GM-CSF, sCD40L, IL-8, MIP-1α, and MIP-1β) could be used for assessing the quality of plasma or serum samples.

Inorganic Phosphorus and Potassium Are Putative Indicators of Delayed Separation of Whole Blood

OBJECTIVES

The delayed separation of whole blood can influence the concentrations of circulating blood components, including metabolites and cytokines. The aim of this study was to determine whether clinical-biochemistry analytes can be used to assess the delayed separation of whole blood.

METHODS

We investigated the plasma and serum concentrations of five clinical-biochemistry analytes and free hemoglobin when the centrifugation of whole blood stored at 4°C or room temperature was delayed for 4 hours, 6 hours, 24 hours, or 48 hours, and compared the values with those of matched samples that had been centrifuged within 2 hours after whole-blood collection.

RESULTS

The inorganic phosphorus (IP) levels in the plasma and serum samples were elevated ≥ 1.5-fold when whole-blood centrifugation was delayed at room temperature for 48 hours. Furthermore, the IP levels in the plasma samples showed excellent assessment accuracy [area under the receiver-operating-characteristic curve (AUC) > 0.9] after a 48-hour delay in whole-blood separation, and high sensitivity (100%) and specificity (95%) at an optimal cutoff point. The IP levels in the serum samples also exhibited good assessment accuracy (AUC > 0.8), and high sensitivity (81%) and specificity (100%). The potassium (K(+)) levels were elevated 1.4-fold in the serum samples following a 48-hour delay in whole-blood separation. The K(+) levels showed excellent assessment accuracy (AUC > 0.9) following a 48-hour delay in whole-blood separation, and high sensitivity (95%) and specificity (91%) at an optimal cutoff point.

CONCLUSION

Our study showed that the IP and K(+) levels in the plasma or serum samples could be considered as putative indicators to determine whether whole-blood separation had been delayed for extended periods.

Biobanking of Cerebrospinal Fluid for Biomarker Analysis in Neurological Diseases

Cerebrospinal fluid (CSF) reflects pathophysiological aspects of neurological diseases, where neuroprotective strategies and biomarkers are urgently needed. Therefore, biobanking is very relevant for biomarker discovery and evaluation for these neurological diseases.An important aspect of CSF biobanking is quality control, needed for e.g. consistent patient follow-up and the exchange of patient samples between research centers. Systematic studies to address effects of pre-analytical and storage variation on a broad range of CSF proteins are needed and initiated.Important features of CSF biobanking are intensive collaboration in international networks and the tight application of standardized protocols. The current adoption of standardized protocols for CSF and blood collection and for biobanking of these samples, as presented in this chapter, enables biomarker studies in large cohorts of patients and controls.In conclusion, biomarker research in neurodegenerative diseases has entered a new era due to the collaborative and multicenter efforts of many groups. The streamlining of biobanking procedures, including sample collection, quality control, and the selection of optimal control groups for investigating biomarkers is an important improvement to perform high quality biomarker studies.

Processing of diagnostic blood specimens: is it really necessary to mix primary blood tubes after collection with evacuated tube system?

BACKGROUND

The preanalytical phase is considered the most vulnerable phase in biopreservation, biobanking, and laboratory diagnostics. Accurate mixing after blood collection is claimed to be important and recommended by the manufacturers.

OBJECTIVE

To evaluate whether it is really necessary to mix the primary blood tubes immediately after blood collection by means of evacuated tube systems.

MATERIAL AND METHODS

Blood from 300 outpatients was equally and randomly divided into three groups: G1, sodium citrate vacuum tubes; G2, lithium heparin vacuum tubes; and G3, K2EDTA vacuum tubes. All vacuum tubes were processed using three different procedures. Procedure 1: Gold Standard (P1): All specimens mixed gently and carefully by inverting five times as recommended; Procedure 2: Rest time (P2): All specimens remained 5 min in the upright position, followed by gentle careful mixing by inverting five times; Procedure 3: No mix (P3): All specimens were left in upright position without mixing afterwards. The influence of the primary mixing tube procedure was evaluated for clinical chemistry, hematology, and coagulation parameters by paired t-test. The bias from the mixing procedure was also compared with quality specifications derived from biological variation.

RESULTS

Significant differences (p<0.017) were found for: i) red blood cell count and hematocrit when P1 was compared with P2; ii) alanine aminotransferase and erythrocyte sedimentation rate when P1 was compared with P3; iii) red blood cell count, hematocrit, and hemolysis index when P2 was compared with P3. Surprisingly, clinically significant differences were found only for sodium when P1 was compared with P2, and P1 was compared with P3. No fibrin filaments or microclots were observed in any samples.

CONCLUSION

Primary blood tubes mixing after collection with evacuated tube system appears to be unnecessary.

Stability of 35 biochemical and immunological routine tests after 10 hours storage and transport of human whole blood at 21°C

Background

Suitable procedures for transport of blood samples from general practitioners to hospital laboratories are requested. Here we explore routine testing on samples stored and transported as whole blood in lithium-heparin or serum tubes.

Methods

Blood samples were collected from 106 hospitalized patients, and analyzed on Architect c8000 or Advia Centaur XP for 35 analytes at base line, and after storage and transport of whole blood in lithium-heparin or serum tubes at 21 ± 1°C for 10 h. Bias and imprecision (representing variation from analysis and storage) were calculated from values at baseline and after storage, and differences tested by paired t-tests. Results were compared to goals set by the laboratory.

Results

We observed no statistically significant bias and results within the goal for imprecision between baseline samples and 10-h samples for albumin, alkaline phosphatase, antitrypsin, bilirubin, creatinine, free triiodothyronine, γ-glutamyl transferase, haptoglobin, immunoglobulin G, lactate dehydrogenase, prostate specific antigen, total carbon dioxide, and urea. Alanine aminotransferase, amylase, C-reactive protein, calcium, cholesterol, creatine kinase, ferritin, free thyroxine, immunoglobulin A, immunoglobulin M, orosomucoid, sodium, transferrin, and triglycerides met goals for imprecision, though they showed a minor, but statistically significant bias in results after storage. Cobalamin, folate, HDL-cholesterol, iron, phosphate, potassium, thyroid stimulating hormone and urate warranted concern, but only folate and phosphate showed deviations of clinical importance.

Conclusions

We conclude that whole blood in lithium-heparin or serum tubes stored for 10 h at 21 ± 1°C, may be used for routine analysis without restrictions for all investigated analytes but folate and phosphate.

Digital pathology and image analysis augment biospecimen annotation and biobank quality assurance harmonization

Standardization of biorepository best practices will enhance the quality of translational biomedical research utilizing patient-derived biobank specimens. Harmonization of pathology quality assurance procedures for biobank accessions has lagged behind other avenues of biospecimen research and biobank development. Comprehension of the cellular content of biorepository specimens is important for discovery of tissue-specific clinically relevant biomarkers for diagnosis and treatment. While rapidly emerging technologies in molecular analyses and data mining create focus on appropriate measures for minimizing pre-analytic artifact-inducing variables, less attention gets paid to annotating the constituent makeup of biospecimens for more effective specimen selection by biobank clients. Both pre-analytic tissue processing and specimen composition influence acquisition of relevant macromolecules for downstream assays. Pathologist review of biorepository submissions, particularly tissues as part of quality assurance procedures, helps to ensure that the intended target cells are present and in sufficient quantity in accessioned specimens. This manual procedure can be tedious and subjective. Incorporating digital pathology into biobank quality assurance procedures, using automated pattern recognition morphometric image analysis to quantify tissue feature areas in digital whole slide images of tissue sections, can minimize variability and subjectivity associated with routine pathologic evaluations in biorepositories. Whole-slide images and pathologist-reviewed morphometric analyses can be provided to researchers to guide specimen selection. Harmonization of pathology quality assurance methods that minimize subjectivity and improve reproducibility among collections would facilitate research-relevant specimen selection by investigators and could facilitate information sharing in an integrated network approach to biobanking.