Accuracy of First and Second Generation Testosterone Assays and Improvement through Sample Extraction

Testosterone analysis in prostate cancer patients

Testosterone is an essential steroid hormone associated with a wide variety of biological processes in humans. In prostate cancer, androgen signaling is an important driver of tumor cell growth. Depletion of gonadal testosterone, achieved by surgical or chemical castration, prevents androgenic signaling and temporally reduces, stops or reverses tumor growth before inevitable progression to castration-resistant prostate cancer occurs. Additional treatment strategies targeting androgenic signaling have become available, although these are without curative intent. While circulating testosterone is also associated with disease risk and potential clinical utility, the main use in the clinical lab is monitoring adequate castration and subsequent resistance to therapy. Adequate castrate testosterone concentrations are currently based on over 50 year-old double-isotope derivative assays that are disputed in automated immunoassay (IA) analysis. The debate has been further fueled with the introduction of mass spectrometry-based assays for testosterone, offering a substantial increase in sensitivity and specificity. In this review, we discuss testosterone regulation and androgen deprivation therapy in prostate cancer. We provide an overview of the developments in testosterone analysis for monitoring adequate castration and resistance to therapy. Current clinical practice and future clinical utility will be discussed. Finally, clinical and research recommendations will be presented.

Hormone Immunoassay Interference: A 2021 Update

Immunoassays are powerful qualitative and quantitative analytical techniques. Since the first description of an immunoassay method in 1959, advances have been made in assay designs and analytical characteristics, opening the door for their widespread implementation in clinical laboratories. Clinical endocrinology is closely linked to laboratory medicine because hormone quantification is important for the diagnosis, treatment, and prognosis of endocrine disorders. Several interferences in immunoassays have been identified through the years; although some are no longer encountered in daily practice, cross-reaction, heterophile antibodies, biotin, and anti-analyte antibodies still cause problems. Newer interferences are also emerging with the development of new therapies. The interfering substance may be exogenous (e.g., a drug or substance absorbed by the patient) or endogenous (e.g., antibodies produced by the patient), and the bias caused by interference can be positive or negative. The consequences of interference can be deleterious when clinicians consider erroneous results to establish a diagnosis, leading to unnecessary explorations or inappropriate treatments. Clinical laboratories and manufacturers continue to investigate methods for the detection, elimination, and prevention of interferences. However, no system is completely devoid of such incidents. In this review, we focus on the analytical interferences encountered in daily practice and possible solutions for their detection or elimination.

A Prospective Study of the Relationship Between Clinical Outcomes After Enzalutamide and Serum Androgen Levels Measured via Liquid Chromatography-tandem Mass Spectrometry in Patients with Castration-resistant Prostate Cancer

Background

Enzalutamide (ENZ) is used to treat patients with castration-resistant prostate cancer (CRPC). However, the kinetics of serum androgens before and after ENZ treatment are unknown.

Objective

To elucidate the kinetics of serum androgens and explore the possibility of identifying a useful marker for predicting the effects of ENZ.

Design setting and participants

We conducted a prospective study from 2014 to 2018 at Gunma University Hospital and related facilities. Data were analyzed for 104 patients with CRPC treated with ENZ.

Outcome measurements and statistical analysis

We measured serum androgen levels using liquid chromatography-tandem mass spectrometry. Relationships with outcomes were assessed using multivariable Cox regression and log-rank analyses.

Results and limitations

The median age of the patients was 73 yr. Median serum testosterone, dihydrotestosterone (DHT), androstenedione, and dehydroepiandrosterone sulfate levels were 49.0, 5.8, 222.2, and 326.3 pg/ml, respectively. We performed multivariate analysis using Cox regression to predict prostate-specific antigen progression-free survival (PSA-PFS) and overall survival (OS). Hemoglobin level (≥12.5 vs <12.5 g/dl), docetaxel treatment history (no vs yes), and DHT level (≥5.9 vs <5.9 pg/ml) were significant predictors of PSA-PFS (p <  0.05). Eastern Cooperative Oncology Group performance status (0 vs. 1-2), hemoglobin level (≥12.5 vs <12.5 g/dl), presence of visceral metastasis (no vs yes), amount of bone metastasis (extent of disease 0-2 vs 3-4), and docetaxel treatment history (no vs yes) were significant predictors of OS (p <  0.05). Binomial logistic analysis of the predictors of any grade of anorexia, malaise, and fatigue showed that the presence of visceral metastasis and a low DHT level (<5.9 pg/ml) were significant.

Conclusions

Our results suggest that serum androgen levels before ENZ treatment may be useful for predicting efficacy, prognosis, and the incidence of adverse events.

Patient summary

We measured blood levels of testosterone and other male hormones before treatment with enzalutamide among men with prostate cancer resistant to castration. We found that the levels of these hormones may be useful for predicting the efficacy of enzalutamide treatment, prognosis, and the occurrence of adverse side effects.

The effect of transgender hormonal treatment on high density lipoprotein cholesterol efflux capacity

BACKGROUND AND AIMS

A decrease in high-density lipoprotein (HDL)-cholesterol concentrations during transgender hormone therapy has been shown. However, the ability of HDL to remove cholesterol from arterial wall macrophages, termed cholesterol efflux capacity (CEC), has proven to be a better predictor of cardiovascular disease (CVD) largely independently of HDL-concentrations. In addition, the serum capacity to load macrophages with cholesterol (cholesterol loading capacity, CLC) represents an index of pro-atherogenic potential. As transgender individuals are exposed to lifelong exogenous hormone therapy (HT), it becomes of interest to study whether HDL-CEC and serum CLC are affected by HT. HDL-CEC and serum CLC have been evaluated in 15 trans men treated with testosterone and in 15 trans women treated with estradiol and cyproterone acetate at baseline and after 12 months of HT.

METHODS

Total HDL-CEC from macrophages and its major contributors, the ATP-binding cassette transporters (ABC) A1 and ABCG1 HDL-CEC and HDL-CEC by aqueous diffusion were determined by a radioisotopic assay. CLC was evaluated in human THP-1 macrophages.

RESULTS

In trans women, total HDL-CEC decreased by 10.8% (95%CI: -14.3;-7.3; p < 0.001), ABCA1 HDL-CEC by 23.8% (-34.7; -12.9; p < 0.001) and aqueous diffusion HDL-CEC by 4.8% (-8.4;-1.1; p < 0.01). In trans men, only aqueous diffusion HDL-CEC decreased significantly, -9.8% (-15.7;-3.9; p < 0.01). ABCG1 HDL-CEC did not change in either group. Serum CLC and HDL subclass distribution were not modified by HT in both groups.

CONCLUSIONS

Total HDL-CEC decreased during HT in trans women, with a specific reduction in ABCA1 CEC. This finding might contribute to a higher CVD risk.

Testosterone and Estrone Increase From the Age of 70 Years: Findings From the Sex Hormones in Older Women Study

CONTEXT

There is a lack of understanding of what is normal in terms of sex steroid levels in older women.

OBJECTIVE

To determine whether sex steroid levels vary with age in and establish reference ranges for women >70 years of age.

DESIGN AND SETTING

Cross-sectional, community-based study.

PARTICIPANTS

Included 6392 women ≥70 years of age.

MAIN OUTCOME MEASURES

Sex steroids measured by liquid chromatography-tandem mass spectrometry. A reference group, to establish sex steroid age-specific reference ranges, excluded women using systemic or topical sex steroid, antiandrogen or glucocorticoid therapy, or an antiglycemic agent.

RESULTS

The reference group of 5326 women had a mean age of 75.1 (±4.2) years, range of 70 to 94.7 years. Median values (range) were 181.2 pmol/L (3.7 to 5768.9) for estrone (E1), 0.38 nmol/L (0.035 to 8.56) for testosterone (T), 2.60 nmol/L (0.07 to 46.85) for dehydroepiandrosterone (DHEA), and 41.6 nmol/L (2.4 to 176.6) for SHBG. Estradiol and DHT were below method sensitivity in 66.1% and 72.7% of the samples, respectively. Compared with women aged 70 to 74 years, women aged ≥85 years had higher median levels of E1 (11.7%, P = 0.01), T (11.3%, P = 0.02), and SHBG (22.7%, P < 0.001) and lower DHEA (30% less, P < 0.001). Women with overweight and obesity had higher E1 (P < 0.001) and T (P < 0.03) and lower SHBG (P < 0.001) than did women with normal body mass index. Smokers had 17.2% higher median T levels (P = 0.005).

CONCLUSION

From the age of 70 years, T and E1 increase with age, despite a steady decline in DHEA. Whether E1 and T are biomarkers for longevity or contribute to healthy aging merits investigation.

Androgens During the Reproductive Years: What Is Normal for Women?

OBJECTIVE

Whether serum androgen levels can identify women with "androgen insufficiency" or "androgen excess" is unresolved; thus, what constitutes "normal" remains uncertain. We sought to determine whether androgens, including 11-oxygenated C19 steroids, vary with age, menstrual cycle, or body mass index (BMI), during the reproductive years.

DESIGN AND SETTING

Cross-sectional study recruited from eastern Australian states.

PARTICIPANTS

A total of 588 women, aged 18 to 39 years, who were not pregnant, lactating, or using systemic hormone therapy, with regular menstrual cycles and no previous diagnosis of polycystic ovarian syndrome.

MAIN OUTCOME MEASURES

Sex steroids measured using liquid chromatography-tandem mass spectrometry.

RESULTS

Testosterone and androstenedione concentrations were significantly higher during the menstrual cycle mid- and luteal phases than in the early follicular phase, with median values across the cycle of 0.34 nmol/L (range, 0.04 to 1.01) and 1.97 nmol/L (range, 0.53 to 7.89), respectively. No cyclical variations were found in dehydroepiandrosterone (DHEA; 4.91 nmol/L; range, 0.08 to 23.51), 11-ketoandrostenedione (11KA; 7.99 nmol/L; range, 0.07 to 31.67), or 11-ketotestosterone (11KT; 1.27 nmol/L; range, 0.03 to 7.61). Overweight women had lower median testosterone (P < 0.05), DHEA (P < 0.05), and 11KA (P < 0.01) levels than normal-weight women. All C19 steroids were significantly lower (P < 0.01) in those aged 35 to 39 years than in those aged 18 to 25 years. The median 11KA/androstenedione (4.3:1) and 11KT/testosterone (3.9:1) ratios did not change with age, after adjustment for BMI and cycle stage.

CONCLUSIONS

We have demonstrated that 11KA and 11KT are stable across the menstrual cycle and make major quantitative contributions to the circulating androgen pool. All C19 androgens declined with age before menopause; hence, age-specific reference ranges are required for the interpretation of androgen levels in premenopausal women.

Global Consensus Position Statement on the Use of Testosterone Therapy for Women

This Position Statement has been endorsed by the International Menopause Society, The Endocrine Society, The European Menopause and Andropause Society, The International Society for Sexual Medicine, The International Society for the Study of Women's Sexual Health, The North American Menopause Society, The Federacion Latinoamericana de Sociedades de Climaterio y Menopausia, The Royal College of Obstetricians and Gynecologists, The International Society of Endocrinology, The Endocrine Society of Australia, and The Royal Australian and New Zealand College of Obstetricians and Gynecologists.

Associations between testosterone and metabolic syndrome in depressed and non-depressed older men and women

OBJECTIVES

Older age and major depressive disorder (MDD) are both risk factors for the development of cardiovascular diseases. Testosterone has been associated with MDD and metabolic syndrome (MetS) in men, although associations in women are less clear. Therefore, we investigated whether testosterone is associated with MetS and whether this association is different for depressed and non-depressed older men and women.

METHODS

In this prospective cohort study, 478 participants (349 patients with MDD and 129 controls) aged between 60 and 93 years from the Netherlands Study of Depression in Older Persons were included. Total testosterone (TT) and sex-hormone binding globulin levels were measured using a second-generation radioimmune assay. Free testosterone (FT) was calculated based on TT. MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

RESULTS

A higher risk for MetS was found in men with low FT and TT (odds ratio [OR]: 0.67, 95% confidence interval [95%CI]: 0.47-0.95 and OR: 0.51, 95%CI: 0.34-0.75), and in women with high FT (OR: 1.41, 95%CI: 1.08-1.82). Strong associations in the same direction were found with adiposity, glucose, and plasma lipid MetS components at baseline, but not with changes in these components at 2-year follow-up. The associations did not significantly differ between MDD patients and controls.

CONCLUSIONS

Independently of having MDD, low testosterone levels in men and, in contrast, high testosterone levels in women were significantly associated with MetS and its components.

Certified testosterone immunoassays for hyperandrogenaemia

BACKGROUND

Testosterone (T) measurement in women is problematic leading to initiatives aiming to improve laboratory standardization of commercial assays. We assessed the impact on the clinical diagnosis of functional hyperandrogenic disorders of a total T immunoassay recently certified by the Centers for Diseases Control and Prevention (CDC).

METHODS

We conducted a cross-sectional study including 263 consecutive adult premenopausal women presenting with functional ovarian hyperandrogenism-including polycystic ovary syndrome (PCOS)-and 73 nonhyperandrogenic female volunteers who served to define reference ranges. Total T was measured by a local routine direct radioimmunoassay and by a CDC-certified immunochemiluminescence assay. The main outcome measures were total and calculated free T concentrations and percentage of patients with hyperandrogenaemia.

RESULTS

Both assays showed a poor concordance for total and calculated free T measurements. Hence, 147 (56%) and 109 (41%) of women had hyperandrogenaemia with the routine and CDC-certified assays, respectively [κ (95%CI): 0.538 (0.441-0.634)]. Free T levels calculated from total T using both assays showed similar correlations with metabolic variables. Women showing hyperandrogenaemia by both methods had the worst metabolic profiles, yet women presenting with hyperandrogenaemia only when using the CDC-certified assay did not show any significant difference compared to nonhyperandrogenic women in anthropometric or metabolic variables. Those women with hyperandrogenaemia only when using the routine assay were more obese and insulin resistant than normoandrogenaemic hirsute patients.

CONCLUSIONS

An isolated androgen measurement, even a very specific one, is unlikely to identify the hyperandrogenic milieu that characterizes patients with functional ovarian hyperandrogenism and PCOS.

The When, What & How of Measuring Vitamin D Metabolism in Clinical Medicine

We now have the ability to measure a number of different vitamin D metabolites with very accurate methods. The most abundant vitamin D metabolite, 25-hydroxyvitamin D, is currently the best marker for overall vitamin D status and is therefore most commonly measured in clinical medicine. The added value of measuring metabolites beyond 25-hydroxyvitamin D, like 1,25-, and 24,25-dihydroxyvitamin D is not broadly appreciated. Yet, in some more complicated cases, these metabolites may provide just the information needed for a legitimate diagnosis. The problem at present, is knowing when to measure, what to measure and how to measure. For 25-hydroxyvitamin D, the most frequently used automated immunoassays do not meet the requirements of today’s standards for certain patient groups and liquid chromatography-tandem mass spectrometry is the desired method of choice in these individuals. The less frequently measured 1,25-dihydroxyvitamin D metabolite enables us to identify a number of conditions, including 1α-hydroxylase deficiency, hereditary vitamin D-resistant rickets and a number of granulomatous diseases or lymphoproliferative diseases accompanied by hypercalcaemia. Furthermore, it discriminates between the FGF23-mediated and non-FGF23-mediated hypophosphatemic syndromes. The 24,25-dihydroxyvitamin D metabolite has proven its value in the diagnosis of idiopathic infantile hypercalcaemia and has the potential of having value in identifying other diseases. For both metabolites, the understanding of the origin of differences between assays is limited and requires further attention. Nonetheless, in every way, appropriate measurement of vitamin D metabolism in the clinical laboratory hinges eminently on the comprehension of the value of the different metabolites, and the importance of the choice of method.

Free Testosterone Reflects Metabolic as well as Ovarian Disturbances in Subfertile Oligomenorrheic Women

BACKGROUND

Diagnosing polycystic ovary syndrome (PCOS) is based on ovulatory dysfunction, ovarian ultrasound data, and androgen excess. Total testosterone is frequently used to identify androgen excess, but testosterone is mainly bound to sex hormone-binding globulin (SHBG) and albumin. Only 1-2% of nonprotein-bound testosterone (so-called free testosterone) is biologically active and responsible for androgen action. Moreover, automated immunoassays which are frequently used for female testosterone measurements are inaccurate.

OBJECTIVE

To assess the clinical usefulness of liquid chromatography-tandem mass spectrometry measured testosterone and calculated free testosterone in subfertile women attending a fertility clinic with oligomenorrhea and suspected PCOS.

METHODS

Hormonal and metabolic parameters were evaluated, and ovarian ultrasound was performed. Total testosterone was measured by liquid chromatography-tandem mass spectrometry. Free testosterone was calculated from total testosterone and SHBG.

RESULTS

Sixty-six women were included in the study. Total testosterone was associated with ovarian volume and antral follicle count but not with metabolic parameters. However, SHBG and calculated free testosterone were associated with both ovarian ultrasound and metabolic parameters, such as BMI and insulin resistance.

CONCLUSIONS

Assessing SHBG and free testosterone is important in evaluating androgen excess in subfertile women with ovulatory dysfunction and suspected PCOS, as it reflects both ovarian and metabolic disturbances.

Comparisons between commercial salivary testosterone enzyme-linked immunosorbent assay kits

INTRODUCTION

Measuring testosterone concentrations is of interest both in clinical situations and for research, the latter expanding rapidly during recent years. An increased demand for convenient methods has prompted a number of companies to develop enzyme-linked immunosorbent assay (ELISA) kits to measure testosterone concentrations in saliva. However, the inter-comparability of kits from different manufacturers have yet to be determined.

AIM OF STUDY

The aim of this study was to compare commercially available ELISA kits from four different manufacturers (Salimetrics, IBL, DRG and Demeditec).

METHODS

Saliva was collected from 50 participants (25 men and 25 women). Each sample was analysed by the four ELISA kits.

RESULTS

The correlations between the ELISA kits from Demeditec, DRG and Salimetrics were moderate to high with r-values > .77; however, proportional errors between the methods calls for caution. The ELISA kit from IBL malfunctioned and no results from this kit was obtained.

CONCLUSIONS

Results from studies using the ELISA kits from Demeditec, DRG and Salimetrics are generally comparable; however, translation using the formulae presented in the current study could increase the accuracy of these comparisons.

Plasma Testosterone and the Course of Major Depressive Disorder in Older Men and Women

OBJECTIVE

To investigate associations between testosterone levels and major depressive disorder (MDD) in older men and women.

METHODS

In a cross-sectional, 2-year prospective analyses within the Netherlands Study on Depression in Older persons cohort study, 469 participants comprised 350 patients with MDD and 119 nondepressed participants in the comparison group (mean age 70.5 ± 7.3 years; 166 [35.4%] men). MDD was assessed by the Composite International Diagnostic Interview. Baseline plasma total testosterone and sex hormone binding globulin (SHBG) were assessed to calculate free testosterone. The Inventory of Depressive Symptomatology was assessed every 6 months.

RESULTS

Whereas SHBG levels did not differ between the depressed/nondepressed groups (F(1,149) = 0.075, p = 0.78), men with MDD had lower mean total and free testosterone levels than the comparison group in the multivariate adjusted analyses (F(1,150) = 7.249, p = 0.008, Cohen's d = 0.51; and F(1,149) = 8.548, p = 0.004 Cohen's d = 0.55, respectively). This could be ascribed to lower testosterone in men with "pure" MDD and not in men with MDD and comorbid anxiety. Nine men (5.4%) had a total testosterone level < 8 nmol/L, of whom 8 suffered from MDD. In women, hormone levels showed no significant difference between the groups. In men (using all five measurement points during follow-up) baseline free testosterone was inversely associated with depression severity in the adjusted analyses (β = -0.15, t(151) = -2.15, p = 0.03).

CONCLUSION

Testosterone levels were lower in men with MDD compared with healthy men after adjustment for confounders, such as body mass index. No significant associations were found in women.

Accuracy-based proficiency testing for testosterone measurements with immunoassays and liquid chromatography-mass spectrometry

BACKGROUND

Accurate testosterone measurements are needed to correctly diagnose and treat patients. Proficiency Testing (PT) programs using modified specimens for testing can be limited because of matrix effects and usage of non-reference measurement procedure (RMP)-defined targets for evaluation. Accuracy-based PT can overcome such limitations; however, there is a lack of information on accuracy-based PT and feasibility of its implementation in evaluation for testosterone measurements.

METHODS

Unaltered, single-donor human serum from 2 male and 2 female adult donors were analyzed for testosterone by 142 NYSDH-certified clinical laboratories using 16 immunoassays and LC-MS/MS methods. Testosterone target values were determined using an RMP.

RESULTS

The testosterone target concentrations for the 4 specimens were 15.5, 30.0, 402 and 498ng/dl. The biases ranged from -17.8% to 73.1%, 3.1% to 21.3%, -24.8% to 8.6%, and -22.1% to 6.8% for the 4 specimens, respectively. Using a total error target of ±25.1%, which was calculated using the minimum allowable bias and imprecision, 73% of participating laboratories had ≥3 of the 4 results within these limits.

CONCLUSIONS

The variability in total testosterone measurements can affect clinical decisions. Accuracy-based PT can significantly contribute to improving testosterone testing by providing reliable data on accuracy in patient care to laboratories, assay manufacturers, and standardization programs.

Advances in bioanalytical techniques to measure steroid hormones in serum

Steroid hormones are measured clinically to determine if a patient has a pathological process occurring in the adrenal gland, or other hormone responsive organs. They are very similar in structure making them analytically challenging to measure. Additionally, these hormones have vast concentration differences in human serum adding to the measurement complexity. GC–MS was the gold standard methodology used to measure steroid hormones clinically, followed by radioimmunoassay, but that was replaced by immunoassay due to ease of use. LC–MS/MS has now become a popular alternative owing to simplified sample preparation than for GC–MS and increased specificity and sensitivity over immunoassay. This review will discuss these methodologies and some new developments that could simplify and improve steroid hormone analysis in serum.

Comparison of 7 Published LC-MS/MS Methods for the Simultaneous Measurement of Testosterone, Androstenedione, and Dehydroepiandrosterone in Serum

BACKGROUND

Recently, LC-MS/MS was stated to be the method of choice to measure sex steroids. Because information on the mutual agreement of LC-MS/MS methods is scarce, we compared 7 published LC-MS/MS methods for the simultaneous measurement of testosterone, androstenedione, and dehydroepiandrosterone (DHEA).

METHODS

We used 7 published LC-MS/MS methods to analyze in duplicate 55 random samples from both men and women. We performed Passing-Bablok regression analysis and calculated Pearson correlation coefficients to assess the agreement of the methods investigated with the median concentration measured by all methods, and we calculated the intraassay CV of each method derived from duplicate results and the CVs between the methods.

RESULTS

Median concentrations of testosterone were 0.22-1.36 nmol/L for women and 8.27-27.98 nmol/L for men. Androstenedione and DHEA concentrations were 0.05-5.53 and 0.58-18.04 nmol/L, respectively. Intraassay CVs were 2.9%-10%, 1.2%-8.8%, 2.7%-13%, and 4.3%-16% for testosterone in women, testosterone in men, androstenedione, and DHEA. Slopes of the regression lines calculated by Passing-Bablok regression analysis were 0.92-1.08, 0.92-1.08, 0.90-1.13, and 0.91-1.41 for all testosterone values, testosterone in women, androstenedione, and DHEA. Intermethod CVs were 14%, 8%, 30%, and 22% for testosterone in women, testosterone in men, androstenedione, and DHEA.

CONCLUSIONS

In general, the LC-MS/MS methods investigated show reasonable agreement. However, some of the assays show differences in standardization, and others show high variation.

Testosterone, free testosterone, and free androgen index in women: Reference intervals, biological variation, and diagnostic value in polycystic ovary syndrome

OBJECTIVE

The objective of our study was to determine reference intervals and biologic variation for testosterone (T), free testosterone (fT), and free androgen index (FAI) in women with accurate methods and to test the discriminative value of these parameters in a polycystic ovary syndrome (PCOS)-population.

METHODS

Serum was obtained daily during a normal menstrual cycle from 25 healthy women (677 data-points). A single serum sample was obtained from 44 PCOS-patients. T was measured by LC–MS/MS and by Architect® 2nd generation T Immunoassay. Sex hormone-binding globulin was measured to calculate fT and FAI. Results: Reference intervals which were established in healthy women with an ovulatory menstrual cycle were T = 0.3-1.6 nmol/L and 0.5-2.0 nmol/L, fT = 5.2-26 pmol/L and 7.2-33 pmol/L, and FAI = 0.4-2.9 and 0.6-4.4, by LC-MS/MS and immunoassay, respectively. T, fT and FAI were higher in PCOS patients than in controls (p b 0.0001). The areas under the curve of receiver operator characteristic (ROC) plots were not different for T, fT, or FAI when T was measured by LC–MS/MS versus immunoassay based on prediction of PCOS. FAI and fT were the strongest predictors of PCOS.

CONCLUSIONS

When based upon the appropriate reference intervals and ROC analysis, LC-MS/MS and second generation immunoassay have equivalent clinical utility for the diagnosis of PCOS.

Clinical endocrinological evaluation of the gonadal axis (testosterone, LH and FSH) in prostate cancer patients switched from a GnRH antagonist to a LHRH agonist

OBJECTIVES

To investigate the levels of testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prostate-specific antigen (PSA) in prostate cancer patients before and after the switch from degarelix to leuprolide treatments.

METHODS

We enrolled 40 treatment-naïve prostate cancer patients who were treated initially with degarelix and were later switched to leuprolide. The subjects were divided into three groups depending on when they were switched to leuprolide: the 3-month group (3m; switched after 84 days, n=10), the 2-month group (2m; 56 days, n=10), and the 1-month group (1m; 28 days, n=20). Patient symptoms and hormone levels were measured after switching therapy. The castration level was defined as a serum testosterone level ≤50 ng/dl.

RESULTS

Thirty-nine subjects (97.5%) achieved castration levels of testosterone (11±5.8 ng/dl) 2 weeks after degarelix was first administered, and the characteristics of these patients were investigated. Testosterone levels increased and exceeded the castration level in one subject each of the 3m (142 ng/dl), 2m (72 ng/dl), and 1m groups (63 ng/dl). All subjects achieved the castration level by day 5. In contrast to testosterone levels, the LH and FSH surge on day 2 was significantly higher in the 1m group than in the other groups. The clinical symptoms were not exacerbated before or after switching in any patients.

CONCLUSIONS

A testosterone surge was observed in 8.3 % of the study patients; however, it was very short-lived and mild. LH and FSH levels were significantly higher 1 month after administration compared with 2 or 3 months after degarelix administration.

Vitamin D supplementation and testosterone concentrations in male human subjects

OBJECTIVE

A possible association between serum 25-hydroxyvitamin D and testosterone levels has been reported; however, contradictory results have emerged.

DESIGN

To investigate a causal link between vitamin D and testosterone status, we studied the effect of vitamin D supplementation on serum testosterone concentrations in three independent intervention studies including male patients with heart failure (study 1), male nursing home residents (study 2) and male non-Western immigrants in the Netherlands (study 3).

METHODS

In study 1, 92 subjects were randomized to either vitamin D (2000 IU cholecalciferol daily) or control. Blood was drawn at baseline, after 3 and 6 weeks. In study 2, 49 vitamin D deficient subjects received either vitamin D (600 IU daily) or placebo. Blood was drawn at baseline, after 8 and 16 weeks. In study 3, 43 vitamin D deficient subjects received either vitamin D (1200 IU daily) or placebo. Blood was drawn at baseline, after 8 and 16 weeks. Serum 25-hydroxyvitamin D levels were measured using LC-MS/MS or radioimmunoassay. Testosterone levels were measured using a 2nd generation immunoassay.

RESULTS

Serum 25-hydroxyvitamin D levels significantly increased in all treatment groups (median increase of 27, 30 and 36 nmol/l in studies 1, 2 3, respectively) but not in the control groups. The documented increase in 25-hydroxyvitamin D levels, however, did not affect mean testosterone concentrations at the end of the study (median increase of 0, 0.5 and 0 nmol/l in studies 1, 2 and 3, respectively).

CONCLUSIONS

In this post hoc analysis of three small clinical trials of limited duration in men with normal baseline testosterone concentrations, vitamin D supplementation was not associated with an increase in circulating testosterone concentrations.

Peculiar observations in measuring testosterone in women treated with oral contraceptives supplemented with dehydroepiandrosterone (DHEA)

Total testosterone is considered to be decreased during the use of combined oral contraceptives. There is, however, considerable concern about the quality of testosterone assays, especially at low levels. We aimed to confirm testosterone levels measured by direct radioimmunoassay in a recent clinical trial with a state-of-the-art LC-MSMS method. Surplus specimens with known testosterone levels collected during the study (Clinical Trial Registration number ISRCTN06414473) were reanalyzed with an LC-MSMS method. This method was compared to another LC-MSMS method that had shown to concur excellently to a reference method. Follow-up experiments were designed to explain the results. In contrast to our expectation, LC-MSMS measurements did not corroborate the data obtained by radioimmunoassay. Subsequent experiments showed that this could be attributed to a strong dependency of the radioimmunoassay on SHBG. Testosterone results (n = 198) obtained by direct radioimmunoassay showed a negative correlation to SHBG levels (r = -0.676; p<0.001). By contrast, testosterone results obtained by LC-MSMS were not related to SHBG (r = 0.100; NS). In conclusion, our results indicate that total testosterone measurements during oral contraceptive use are unreliable when performed with assays sensitive to the SHBG concentration. The discrepancy with the literature can most likely be explained by the sensitivity of the immunoassay used to SHBG. Given the sharp increase in SHBG during the use of many oral contraceptives, total testosterone may not decrease, whereas its bioavailability, estimated by free testosterone levels, will be diminished. Studies aiming at restoration of testosterone homeostasis during oral contraception need to take this into account.

Challenges and improvements in testosterone and estradiol testing

Assays that measure steroid hormones in patient care, public health, and research need to be both accurate and precise, as these criteria help to ensure comparability across all clinical and research applications. This review addresses major issues relevant to assay variability and describes recent activities by the US Centers for Disease Control and Prevention (CDC) to improve assay performance. Currently, high degrees of accuracy and precision are not always met for testosterone and estradiol measurements; although technologies for steroid hormone measurement have advanced significantly, measurement variability within and across laboratories has not improved accordingly. Differences in calibration and specificity are discussed as sources of variability in measurement accuracy. Ultimately, a combination of factors appears to cause inaccuracy of steroid hormone measurements, with nonuniform assay calibration and lack of specificity being two major contributors to assay variability. Within-assay variability for current assays is generally high, especially at low analyte concentrations. The CDC Hormone Standardization (HoSt) Program is improving clinical assays, as evidenced by a 50% decline in mean absolute bias between mass spectrometry assays and the CDC reference method from 2007 to 2011. This program provides the measurement traceability to CDC reference methods and helps to minimize factors affecting measurement variability.

Free testosterone: clinical utility and important analytical aspects of measurement

Testosterone, the most abundant androgen in men, is a steroid hormone that is synthesized predominantly by the testes. In women, minor amounts are synthesized in the ovaries. Androgen precursors are also produced and secreted from the adrenal glands in both sexes, where they undergo peripheral conversion to testosterone. Circulating concentrations are approximately 15-25 times higher in adult men compared to women. Maintenance of these levels is necessary for development and maintenance of secondary sexual characteristics, libido, growth, prevention of osteoporosis, and most importantly in men, spermatogenesis. Most testosterone circulates tightly bound to sex hormone-binding globulin (SHBG) or weakly bound to albumin. A minor amount circulates as free testosterone, and it is believed that this is the metabolically active fraction. Measurement of free testosterone is important in the diagnosis of many diseases, most importantly disorders of androgen deficiency in men (i.e., hypogonadism) and androgen excess in women (i.e., polycystic ovary syndrome and hirsutism). Many methodologies are available for free testosterone measurement including the reference methods (equilibrium dialysis and ultrafiltration), analog immunoassay, and calculated free testosterone based on measurement of total testosterone, SHBG, and albumin. Moreover, measurement of bioavailable testosterone, a combination of albumin-bound and free testosterone, also has clinical utility and can be measured by selective protein precipitation or calculation. In this review, the advantages and limitations of each of these methods will be discussed in the context of clinical utility and implementation into a routine hospital laboratory. Furthermore, up and coming methodologies for free testosterone measurement, including liquid chromatography-tandem mass spectrometry, will also be discussed.

The effect of combined oral contraception on testosterone levels in healthy women: a systematic review and meta-analysis

BACKGROUND; Combined oral contraceptives (COCs) reduce levels of androgen, especially testosterone (T), by inhibiting ovarian and adrenal androgen synthesis and by increasing levels of sex hormone-binding globulin (SHBG). Although this suppressive effect has been investigated by numerous studies over many years, to our knowledge no systematic review concerning this issue had been performed. This systematic review and meta-analysis was performed to evaluate the effect of COCs on concentrations of total T, free T and SHBG in healthy women and to evaluate differences between the various types of COCs (e.g. estrogen dose, type of progestin) and the assays used to assess total T and free T.

METHODS

A review of the literature was performed using database searches (MEDLINE, EMBASE and the Cochrane Central Register of Clinical Trials) and all publications (from inception date until July 2012) investigating the effect of COCs on androgen levels in healthy women were considered eligible for selection. Three reviewers were involved in study selection, data extraction and critical appraisal. For the meta-analysis, data on total T, free T and SHBG were extracted and combined using random effects analysis. Additional subgroup analyses were performed to evaluate differences between the various types of COCs (e.g. estrogen dose, type of progestin) and the assays used to assess total T or free T.

RESULTS

A total of 151 records were identified by systematic review and 42 studies with a total of 1495 healthy young women (age range: 18-40 years) were included in the meta-analysis. All included studies were experimental studies and 21 were non-comparative. Pooling of the results derived from all the included papers showed that total T levels significantly decreased during COC use [mean difference (MD) (95% confidence interval, CI) -0.49 nmol/l (-0.55, -0.42); P < 0.001]. Significantly lower levels of free T were also found [relative change (95% CI) 0.39 (0.35, 0.43); P < 0.001], with a mean decrease of 61%. On the contrary, SHBG concentrations significantly increased during all types of COC use [MD (95% CI) 99.08 nmol/l (86.43, 111.73); P < 0.001]. Subgroup analyses revealed that COCs containing 20-25 µg EE had similar effects on total and free T compared with COCs with 30-35 µg EE. In addition, suppressive effects on T levels were not different when comparing different types of progestins. However, subgroup analyses for the estrogen dose and the progestin type in relation to changes in SHBG levels did show significant differences: COCs containing second generation progestins and/or the lower estrogen doses (20-25 µg EE) were found to have less impact on SHBG concentrations.

CONCLUSIONS

The current literature review and meta-analysis demonstrates that COCs decrease circulating levels of total T and free T and increase SBHG concentrations. Due to the SHBG increase, free T levels decrease twice as much as total T. The estrogen dose and progestin type of the COC do not influence the decline of total and free T, but both affect SHBG. The clinical implications of suppressed androgen levels during COC use remain to be elucidated.

Complex Biological Pattern of Fertility Hormones in Children and Adolescents: A Study of Healthy Children from the CALIPER Cohort and Establishment of Pediatric Reference Intervals

BACKGROUND

Pediatric endocrinopathies are commonly diagnosed and monitored by measuring hormones of the hypothalamic-pituitary-gonadal axis. Because growth and development can markedly influence normal circulating concentrations of fertility hormones, accurate reference intervals established on the basis of a healthy, nonhospitalized pediatric population and that reflect age-, gender-, and pubertal stage–specific changes are essential for test result interpretation.

METHODS

Healthy children and adolescents (n = 1234) were recruited from a multiethnic population as part of the CALIPER study. After written informed parental consent was obtained, participants filled out a questionnaire including demographic and pubertal development information (assessed by self-reported Tanner stage) and provided a blood sample. We measured 7 fertility hormones including estradiol, testosterone (second generation), progesterone, sex hormone–binding globulin, prolactin, follicle-stimulating hormone, and luteinizing hormone by use of the Abbott Architect i2000 analyzer. We then used these data to calculate age-, gender-, and Tanner stage–specific reference intervals according to Clinical Laboratory Standards Institute C28-A3 guidelines.

RESULTS

We observed a complex pattern of change in each analyte concentration from the neonatal period to adolescence. Consequently, many age and sex partitions were required to cover the changes in most fertility hormones over this period. An exception to this was prolactin, for which no sex partition and only 3 age partitions were necessary.

CONCLUSIONS

This comprehensive database of pediatric reference intervals for fertility hormones will be of global benefit and should lead to improved diagnosis of pediatric endocrinopathies. The new database will need to be validated in local populations and for other immunoassay platforms as recommended by the Clinical Laboratory Standards Institute.

Relationship between body mass index and serum testosterone concentration in patients receiving luteinizing hormone-releasing hormone agonist therapy for prostate cancer

OBJECTIVE

To evaluate the relationship between the body mass index (BMI) and serum testosterone concentrations in men receiving luteinizing hormone-releasing hormone (LHRH) agonist therapy for prostate cancer.

MATERIALS AND METHODS

A total of 66 white men were included in the present study. All subjects had received LHRH agonist therapy for ≥ 3 months. The BMI was calculated, and the subjects were classified as normal weight (i.e. BMI <25 kg/m(2)), overweight (BMI 25-30 kg/m(2)), or obese (BMI >30 kg/m(2)). The serum testosterone concentration was determined using the highly sensitive isotope dilution-liquid chromatography-tandem mass spectrometry technique. The sex hormone-binding globulin level was determined using an immunometric assay, and the free serum testosterone concentration was calculated.

RESULTS

The median serum testosterone concentration of the patients with a BMI <25 kg/m(2) was 5.5 ng/dL. The patients with a BMI of 25-30 kg/m(2) had a median serum testosterone concentration of 3.8 ng/dL. Those patients with a BMI >30 kg/m(2) had a median concentration of 5.7 ng/dL. No significant difference in the serum testosterone concentrations among the 3 groups was found. The sex hormone-binding globulin levels declined with an increasing BMI. The concentration of free testosterone was significantly greater in the obese men.

CONCLUSION

Using an ultrasensitive technique of serum testosterone measurement, the present data have shown that no difference exists in the serum testosterone concentration in the castrate range among normal weight, overweight, and obese patients receiving LHRH agonist therapy for prostate cancer. From our findings and current knowledge, more stringent follow-up or changes in dosage or dosage intervals of LHRH agonist therapy in those with a greater or high BMI is not warranted.

Dynamics of serum testosterone during the menstrual cycle evaluated by daily measurements with an ID-LC-MS/MS method and a 2nd generation automated immunoassay

BACKGROUND

Testosterone concentrations in normally cycling women are assumed to be elevated around the time of ovulation. The clinical relevance of changing testosterone concentrations during the menstrual cycle, however, is unclear. Poor performance of current direct immunoassays for testosterone at low concentrations confounds this issue. Therefore, our objective was to assess daily testosterone fluctuation during the menstrual cycle by a thoroughly validated isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method and to evaluate whether an ARCHITECT® 2nd Generation Testosterone fully automated immunoassay is equally suited for this purpose.

METHODS

Testosterone was measured in serum obtained daily during the menstrual cycle of 25 healthy women, characterized by biochemical and physical examination.

RESULTS

Performance of the ID-LC-MS/MS method was concordant with a published reference method (y=1.007x-0.056 nmol/L; r=0.9998). Comparison of the immunoassay to ID-LC-MS/MS yielded y=1.095x+0.104 nmol/L (r=0.9031). Overall, testosterone concentrations were higher mid-cycle, but a peak was not discernible in each individual. Apart from a persistent positive bias, the immunoassay measured the same testosterone profiles as the ID-LC-MS/MS method. The reference interval in women was 0.30-1.69 nmol/L (8.7-48.7 ng/dL) for ID-LC-MS/MS and 0.50-2.00 nmol/L (14.4-57.7 ng/dL) for the immunoassay.

CONCLUSION

The elevation of mid-cycle testosterone concentrations is statistically significant, although not clinically relevant since day-to-day variation is higher and independent of the menstrual cycle. In this light, a single testosterone measurement might not be reflective of the overall testosterone status in an individual. Measurements obtained using the 2nd generation immunoassay gave comparable results across the menstrual cycle.