An audit of the measurement and reporting of male testosterone levels in UK clinical biochemistry laboratories

Impact of Variation between Assays and Reference Intervals in the Diagnosis of Endocrine Disorders

Method-related variations in the measurement of hormones and the reference intervals used in the clinical laboratory can have a significant, but often under-appreciated, impact on the diagnosis and management of endocrine disorders. This variation in laboratory practice has the potential to lead to an errant approach to patient care and thus could cause harm. It may also be the source of confusion or result in excessive or inadequate investigation. It is important that laboratory professionals and clinicians know about these impacts, their sources, and how to detect and mitigate them when they do arise. In this review article, we describe the historical and scientific context from which inconsistency in the clinical laboratory arises. Examples from the published literature of the impact of the method, reference interval, and clinical decision threshold-related discordances on the assessment and monitoring of various endocrine disorders are discussed to illustrate the sources, causes, and effects of this variability. Its potential impact on the evaluation of growth hormone deficiency and excess, thyroid and parathyroid disorders, hyperandrogenism, hypogonadism, glucocorticoid excess and deficiency, and diabetes mellitus is elaborated. Strategies for assessment and mitigation of the discordance are discussed. The clinical laboratory has a responsibility to recognise and address these issues, and although a lot has been accomplished in this area already, there remains more to be done.

Establishing metrological traceability for small molecule measurands in laboratory medicine

For molecules that can be well described metrologically in the sense of the definition of measurands, and which can also be recorded analytically as individual substances, reference measurement service traceability to a metrologically sound foundation is a necessity. The establishment of traceability chains must be initiated by National Metrology Institutes (NMIs) according to applicable standards; they are at the top and leading position in this concept. If NMIs are not in the position to take up this task, alternative approaches must be sought. Traceability initiatives established by in vitro device industry or academia must meet the quality standards of NMIs. Adherence to International Organization for Standardization (ISO) procedure 15193 must be a matter of course for the establishment of reference measurement procedures (RMPs). Certified reference material (CRM) characterization must be thorough, e.g., by the application of quantitative nuclear magnetic resonance measurements and by adherence to ISO 15194. Both for RMPs and CRMs Joint Committee for Traceability in Laboratory Medicine (JCTLM) listing must be the ultimate goal. Results must be shared in a transparent manner to allow other stakeholders including NMIs to reproduce and disseminate the reference measurement procedures.

Standardising the biochemical confirmation of adult male hypogonadism: A joint position statement by the Society for Endocrinology and Association of Clinical Biochemistry and Laboratory Medicine

BACKGROUND

Inter-assay variation between different immunoassays and different mass spectrometry methods hampers the biochemical confirmation of male hypogonadism. Furthermore, some laboratories utilise assay manufacturer reference ranges that do not necessarily mirror assay performance characteristics, with the lower limit of normality ranging from 4.9 nmol/L to 11 nmol/L. The quality of the normative data underlying commercial immunoassay reference ranges is uncertain.

DESIGN

A working group reviewed published evidence and agreed upon standardised reporting guidance to augment total testosterone reports.

RESULTS

Evidence-based guidance on appropriate blood sampling, clinical action limits, and other major factors likely to affect the interpretation of results are provided.

CONCLUSIONS

This article aims to improve the quality of the interpretation of testosterone results by non-specialist clinicians. It also discusses approaches for assay harmonisation which have been successful in some but not all healthcare systems.

Recommendations for the measurement of sexual steroids in clinical practice. A position statement of SEQCML/SEEN/SEEP

The proper clinical approach to a wide range of disorders relies on the availability of accurate, reproducible laboratory results for sexual steroids measured using methods with a high specificity and sensitivity. The chemiluminescent immunoassays currently available have analytical limitations with significant clinical implications. This position statement reviews the current limitations of laboratory techniques for the measurement of estradiol and testosterone and their impact on diverse clinical scenarios. A set of recommendations are provided to incorporate steroid hormone analysis by mass spectrometry in national health systems. International societies have recommended this methodology for a decade.

Diagnosis of hypogonadism in ageing men

To make the diagnosis of hypogonadism in an ageing man, in absence of rare organic cause often referred to as functional or late onset hypogonadism (LOH), he should present with a clinical syndrome suggestive of androgen deficiency and have consistently low serum testosterone (T) levels. This does not differ from the diagnosis of any other form of hypogonadism. Particular to LOH diagnostic are uncertainties surrounding this entity: signs and symptoms of androgen deficiency (including sexual symptoms) are nonspecific in older men; clinical significance of only moderately low T levels is uncertain; comorbidity plays a substantial role with potential for reversibility; the place of T therapy in these men is debatable. This context demands for a pragmatic, but appropriately conservative approach to diagnosis. Evaluation should be stepwise with clinical evaluation, if suggestive for androgen deficiency, followed by measurement of a fasting morning serum T, if unequivocally low to be confirmed in a separate morning sample by a second low T or, if initial T borderline low or in presence of factors known to affect SHBG, by a low calculated free T level. All other (free) T results make hypogonadism an unlikely cause of the patient's symptoms. In the absence of consensus cut-off levels for total and free T in the published clinical guidelines for diagnosis of hypogonadism, it seems appropriate in the context of LOH to use stringent criteria indicating a convincingly low serum T. The approach to the diagnosis of LOH is not fundamentally different from that of other forms of hypogonadism but should put extra weight on prioritizing the shunning of overdiagnosis above the risk of underdiagnosis.

Diagnosis and Evaluation of Hypogonadism

A systematic approach to diagnose hypogonadism initially establishes the presence of symptoms/signs of testosterone deficiency, considers other potential causes of manifestations, and excludes conditions that transiently suppress testosterone. Hypogonadism is confirmed by measuring fasting serum total testosterone in the morning on at least 2 separate days, or free testosterone by equilibrium dialysis or calculated free testosterone in men with conditions that alter sex hormone-binding globulin or serum total testosterone near lower limit of normal. To guide management, further evaluation is performed to identify the specific cause of hypogonadism and whether it is potentially reversible or an irreversible pathologic disorder.

Clinical characteristics and comorbidities associated with testosterone prescribing in men

OBJECTIVE

Testosterone replacement therapy (TRT) is recommended for the treatment of symptomatic hypogonadism in men. Data on prescription behaviours are, however, limited and conflicting. The objective of this study was to investigate clinical characteristics associated with the likelihood of being prescribed TRT by general practitioners (GP) in North-West London (NWL).

DESIGN

Retrospective cohort study using Discover database of GP-registered patients in NWL between 2015 and 2019.

PATIENTS

We identified 20,299 men aged ≥18 years with serum total testosterone measurement (TT) and without prior TRT prescription records.

MEASUREMENTS

We determined whether TRT was subsequently commenced, while analysing clinical characteristics related to hypogonadism.

RESULTS

Of all men having TT measurement, 19,583 (96.4%) were not commenced on TRT (Group A) and 716 (3.5%) men were commenced on TRT (Group B). Men prescribed TRT (Group B) had higher mean age, body mass index (BMI) and higher risks of hypertension, depression type 2 diabetes and ischaemic heart disease; conversely, men in Group B had lower mean pretreatment TT and were less likely to have prostate cancer. Four-hundred and thirty-six men (24.3%) with TT < 8 nmol/L and symptoms of low libido were not prescribed TRT.

CONCLUSIONS

Our study highlights several factors which may influence the decisions made by clinicians when initiating TRT in primary care. Clearer guidance for clinicians may help to improve the consistency of treatment of men with hypogonadism.

Is a fasting testosterone level really necessary for the determination of androgen status in men?

BACKGROUND

As circulating testosterone may be suppressed in the post-prandial state, it has been recommended that measurements are carried out with the patient fasted.

OBJECTIVES

In this regard, we assessed the effect of fasting/non-fasting status on total testosterone (T) levels in men.

MATERIALS AND METHODS

Data was collected in a single UK Hospital in men with two serum T requests taken within a 6-month period of each other and sampled at a time of day ≤ 2 h apart. Three groups were established, with T levels compared via signed-rank test in men with both a fasting and non-fasting sample (Group 1; n = 69), and in men with paired non-fasting (Group 2; n = 126) and paired fasting (Group 3; n = 18) samples. The differences in T levels between the paired samples was compared between the three groups using the rank-sum test and also via multiple regression analysis with the groups factorised.

RESULTS

Median (Interquartile Range, IQR) age did not vary significantly between Groups 1, 2 and 3 at 49 (38-56), 51.5 (42-60) and 51.5 (40-59) years, respectively. No significant difference (p = 0.89) was found between the T levels in Group 1 with non-fasting (median (IQR) T = 11.1 (9.3-13.6) nmol/L) versus fasting samples T = 10.8 (8.9-14.1) nmol/L). Paired T levels did not significantly differ in each of the other two groups (2 and 3). There was no significant association between the differences in paired T levels between the three groups, even when the model was adjusted for age and time, with Group 1 (as reference) versus Group 2 (p = 0.79) and versus Group 3 (p = 0.63).

DISCUSSION

We found no significant differences between fasting and non-fasting T levels. A definitive confirmatory study is required to determine whether fasting status is necessary to diagnose hypogonadism.

CONCLUSION

Non-requirement of fasting status when checking testosterone levels would remove a major hurdle in the diagnosis of hypogonadism.

Lessons learnt from the variation across 6741 family/general practices in England in the use of treatments for hypogonadism

INTRODUCTION

We have previously reported rates of diagnosis of male hypogonadism in United Kingdom (UK) general practices. We aimed to identify factors associated with testosterone prescribing in UK general practice.

METHODS

We determined for 6741 general practices in England, the level of testosterone prescribing in men and the relation between volume of testosterone prescribing and (1) demographic characteristics of the practice, (2) % patients with specific comorbidities and (3) national GP patient survey results.

RESULTS

The largest volume (by prescribing volume) agents were injectable preparations at a total cost in the 12-month period 2018/19 of £8,172,519 with gel preparations in second place: total cost £4,795,057. Transdermal patches, once the only alternative to testosterone injections or implants, were little prescribed: total cost £222,022. The analysis accounted for 0.27 of the variance in testosterone prescribing between general practices. Thus, most of this variance was not accounted for by the analysis. There was a strong univariant relation (r = .95, P < .001) between PDE5-I prescribing and testosterone prescribing. Other multivariant factors independently linked with more testosterone prescribing were as follows: HIGHER proportion of men with type 2 diabetes(T2DM) on target control (HbA1c ≤ 58 mmol/mol) and HIGHER overall practice rating on the National Patient Survey for good experience, while non-white ethnicity and socio-economic deprivation were associated with less testosterone prescribing. There were a number of comorbidity factors associated with less prescribing of testosterone (such as T2DM, hypertension and stroke/TIA).

CONCLUSION

Our analysis has indicated that variation between general practices in testosterone prescribing in a well developed health economy is only related to small degree (r²  = 0.27) to factors that we can define. This suggests that variation in amount of testosterone prescribed is largely related to general practitioner choice/other factors not studied and may be amenable to measures to increase knowledge/awareness of male hypogonadism, with implications for men's health.

Waist Circumference Is More Closely Associated with Hypogonadism than Is Hyperglycemia, Independent of BMI in Middle-Aged Men

INTRODUCTION

To evaluate whether waist circumference (WC) or hyperglycemia is more closely associated with hypogonadism in middle-aged men. Research Design and Methods. This cross-sectional study analyzed male participants under 65 years old from the MJ Health Screening Center in Taiwan from 2007 to 2016. Basic patient characteristics with relevant parameters were obtained. We used the chi-square test to perform a correlation analysis for HbA1c and WC between participants with and without hypogonadism. A one-way ANOVA with post hoc Scheffe's method was applied to compare the mean testosterone (T) among the HbAlc and WC groups (normal blood sugar with normal WC (NBSNW), abnormal blood sugar with normal WC (ABSNW), normal blood sugar with abnormal WC (NBSAW), and abnormal blood sugar with abnormal waist circumference (ABSAW)).

RESULTS

The 5,680 participants were divided into two groups based on the presence (n = 599) or absence of hypogonadism (n = 5,081), which was defined as total testosterone (TT) < 300 ng/dL. The mean TT of group NBSAW (443.71 ± 220.59 ng/dl) was significantly lower than that of group ABSNW (506.64 ± 191.08 ng/dl, p < 0.001). Moreover, the mean TT of group ABSAW (398.89 ± 146.24 ng/dl) was significantly lower than that of group ABSNW (506.64 ± 191.08 ng/dl, p < 0.001). The ORs after adjusting for BMI, TG, HDL, SBP, and DBP were statistically significant when comparing NBSAW vs. NBSNW (OR = 2.846; 95%CI = 2.266-3.575; p < 0.001), ABSNW vs. NDNW (OR = 1.693; 95%CI = 1.309-2.189; p < 0.001), and ABSAW vs. NBSNW (OR = 4.613; 95%CI = 3.634-5.856; p < 0.001).

CONCLUSION

The current study showed that WC should be the risk factor that is more closely associated with hypogonadism than hyperglycemia in middle-aged men.

Association Between Low Serum Testosterone and the Development of Metabolic Syndrome in Elderly Taiwanese Men

PURPOSE

To assess the association between serum testosterone (T) and metabolic syndrome (MS) in different age groups in Taiwanese men.

MATERIALS AND METHODS

Male participants, regardless of age or any underlying disease, were identified from MJ Health Screening Center in Taiwan from 2007 to 2016 for this cross-sectional study. They were divided into three groups according to age, and further classified according to MS diagnosis. Basic patient characteristics with relevant parameters were obtained. One-way ANOVA of mean T values between different numbers of measures that exceeds the cut-off values of MS components was performed to assess the relationship of T and MS. Logistic regression analysis was also used to estimate the risk for MS with each increment in T, age, and BMI.

RESULTS

A total of 4,931 men were included. The MS group had significantly lower serum T levels compared to the non-MS group in each age group. The one-way ANOVA found the mean value of T was significantly higher in patients without MS component (6.19±2.12 ng/mL) than those with 1-5 MS components (with one MS component: 5.48±2.13 ng/mL, two MS components: 4.93±2.03 ng/mL, three MS components: 4.37±1.60 ng/mL, four MS components: 4.13±2.89 ng/mL, five MS components: 3.74±1.27 ng/mL, and P<0.001). There was no significant difference between the patients with three components and the patients with four or five components. Logistic regression models with age stratification showed T with lower odds ratio (OR) for MS after adjusting for BMI in those ≥65 years old (OR=0.693; 95% CI=0.559-0.858; P<0.001); 50-64 years old (OR=0.868; 95% CI=0.802-0.940; P<0.001) and <50 years old (OR=0.810; 95% CI=0.758-0.865; P<0.001).

CONCLUSION

Lower serum T was strongly associated with MS, with the predictive value increasing with age in Taiwanese men.