Classic and 11-oxygenated androgens in serum and saliva across adulthood: a cross-sectional study analyzing the impact of age, body mass index, and diurnal and menstrual cycle variation.

OBJECTIVE: 11-oxygenated androgens significantly contribute to the circulating androgen pool. Understanding the physiological variation of 11-oxygenated androgens and their determinants is essential for clinical interpretation, for example, in androgen excess conditions. We quantified classic and 11-oxygenated androgens in serum and saliva across the adult age and body mass index (BMI) range, also analyzing diurnal and menstrual cycle-dependent variation. DESIGN: Cross-sectional. Morning serum samples were collected from 290 healthy volunteers (125 men, 22-95 years; 165 women, 21-91 years). Morning saliva samples were collected by a sub-group (51 women and 32 men). Diurnal saliva profiles were collected by 13 men. Twelve women collected diurnal saliva profiles and morning saliva samples on 7 consecutive days during both follicular and luteal menstrual cycle phases. METHODS: Serum and salivary steroids were quantified by liquid chromatography-tandem mass spectrometry profiling assays. RESULTS: Serum classic androgens decreased with age-adjusted BMI, for example, %change kg/m2 for 5α-dihydrotestosterone: men -5.54% (95% confidence interval (CI) -8.10 to -2.98) and women -1.62% (95%CI -3.16 to -0.08). By contrast, 11-oxygenated androgens increased with BMI, for example, %change kg/m2 for 11-ketotestosterone: men 3.05% (95%CI 0.08-6.03) and women 1.68% (95%CI -0.44 to 3.79). Conversely, classic androgens decreased with age in both men and women, while 11-oxygenated androgens did not. Salivary androgens showed a diurnal pattern in men and in the follicular phase in women; in the luteal phase, only 11-oxygenated androgens showed diurnal variation. CONCLUSIONS: Classic androgens decrease while active 11-oxygenated androgens increase with increasing BMI, pointing toward the importance of adipose tissue mass for the activation of 11-oxygenated androgens. Classic but not 11-oxygenated androgens decline with age.

11-Oxygenated C19 steroids are the predominant androgens responsible for hyperandrogenemia in Cushing's disease.

Background: Symptoms of hyperandrogenism are common in patients with Cushing's disease (CD), yet they are not sufficiently explained by androgen concentrations. In this study, we analyzed the contribution of 11-oxygenated C19 steroids (11oxC19) to hyperandrogenemia in female patients with CD. Methods: We assessed saliva day profiles in females with CD pre (n = 23) and post (n = 13) successful transsphenoidal surgery, 26 female controls, 5 females with CD treated with metyrapone and 5 treated with osilodrostat for cortisol, cortisone, androstenedione (A4), 11-hydroxyandrostenedione (11OHA4), testosterone (TS), 11-ketotestosterone (11KT), as well as metabolites of classic and 11-oxygenated androgens in 24-h urine. In addition, morning baseline levels of gonadotropins and estradiol, sex hormone-binding globulin, cortisol and dehydroepiandrosterone sulfate (DHEAS) in serum and adrenocorticotrophic hormone in plasma in patients and controls were investigated. Results: Treatment-naïve females with CD showed a significantly elevated area under the curve of 11OHA4 and 11KT in saliva throughout the day compared to controls (11OHA4 mean rank difference (mrd) 18.13, P = 0.0002; 11KT mrd 17.42; P = 0.0005), whereas A4, TS and DHEAS were comparable to controls. Gonadotropin concentrations were normal in all patients with CD. After transsphenoidal surgery, 11oxC19 and their metabolites dropped significantly in saliva (11OHA4 P < 0.0001; 11KT P = 0.0010) and urine (11-oxo-androsterone P = 0.0011; 11-hydroxy-androsterone P < 0.0001), treatment with osilodrostat and metyrapone efficaciously blocked 11oxC19 synthesis. Conclusion: Hyperandrogenemia in CD is predominantly caused by excess of 11oxC19 steroids.

An LC-MS/MS assay for analysis of equilibrium angiotensin II in human serum.

BACKGROUND: The current first-line screening test for primary hyperaldosteronism is the plasma aldosterone:renin ratio; however, renin assays have several disadvantages and the ARR is affected by medications and physiological factors. Angiotensin II is a key biologically active hormone in the renin-angiotensin-aldosterone system. It has been suggested that measurement of equilibrium levels of this peptide, involving an in vitro incubation of serum prior to analysis, may provide a better marker of renin-angiotensin-aldosterone system activity than renin. METHODS: An eqAng II LC-MS/MS assay was developed, optimized and validated. Serum samples were incubated at 37°C for 45 min prior to stabilization with cold EDTA solution, solid phase extraction and LC-MS/MS analysis. Stability in whole blood and the effect of cryoactivation were assessed. For comparison to the current screening test, 150 anonymized patients' samples were analysed for eqAng II, renin activity and aldosterone (all by LC-MS/MS). RESULTS: The assay had good precision, minimal bias and acceptable recovery. EqAng II did not change significantly when whole blood samples were stored for up to 72 h, and cryoactivation was only observed for pregnant patients. EqAng II was significantly correlated with renin, and the aldosterone:eqAng II ratio had a strong positive correlation with the aldosterone:renin ratio. CONCLUSIONS: An LC-MS/MS assay for eqAng II has been developed which shows promise as an alternative screening test for primary hyperaldosteronism. Compared to renin assays, it is quicker, simpler and less likely to be affected by anti-hypertensive medications. Further clinical validation in hypertensive patients would be required prior to implementation.

Quantification of testosterone, androstenedione and 17-hydroxyprogesterone in whole blood collected using Mitra microsampling devices.

BACKGROUND: Measurement of testosterone (T), androstenedione (A4) and 17-hydroxyprogesterone (17OHP) usually requires a venous serum sample which may have implications for sample stability or collection. OBJECTIVE: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed for samples collected using Mitra devices. Analytical validation was completed, and sample comparisons were undertaken to assess Mitra versus venous samples. METHOD: Sample was combined with deionized water and internal standard. After mixing, MTBE was added for extraction. The supernatant was transferred to a deep-well plate and dried prior to re-constitution. A HSS T3 column and Waters TQS Micro was used, the detected quantifier transitions were T m/z 289.2 > 96.95, A4 287.2 > 96.95 and 17OHP 331.25 > 96.95. RESULTS: Mean recovery was 102% for T, 98% for A4 and 97% for 17OHP. Lower limit of quantification was 1 nmol/L for T/A4 and 4 nmol/L for 17OHP. T was linear up to 41.6 nmol/L, A4 41.9 nmol/L and 17OHP 72.6 nmol/L. Ion suppression was <10% for all analytes. A4 and 17OHP showed minimal bias for Mitra samples collected from finger prick blood. The bias for T differed between capillary and venous blood, indicating differences in constituency. DISCUSSION: A simple, fast and reproducible LC-MS/MS assay has been developed for measurement of blood collected using Mitra devices for T, A4 and 17OHP. Further comparisons with serum and capillary blood collected onto Mitra devices serum may pave the way for future use in a clinical setting.

Development of a total serum testosterone, androstenedione, 17-hydroxyprogesterone, 11ß-hydroxyandrostenedione and 11-ketotestosterone LC-MS/MS assay and its application to evaluate pre-analytical sample stability.

Background Classically, serum testosterone (T) and androstenedione (A4) have been the mainstay for the biochemical assessment of hyperandrogenism. However, recent evidence suggests 11ß-hydroxyandrostenedione (11OHA4) and 11-ketotestosterone (11KT) may also be important. Here, we describe the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for quantitation of total serum T, A4, 17-hydroxyprogesterone (17OHP), 11OHA4 and 11KT. In addition, we applied the method to assess pre-analytical stability. Methods An isotopically labelled internal standard was added to samples prior to supported liquid extraction (SLE). Extracts were analysed using LC-MS/MS to detect T/A4/17OHP/11OHA4 and 11KT along with their corresponding internal standards. Samples (n = 7) were collected from healthy volunteers (n = 14) and left incubated at 20 °C for up to 72 h. Tubes were retrieved at select time points, centrifuged, separated and frozen prior to analysis. Results The total run time was 4 min. For all analytes, intra- and inter-assay imprecision did not exceed 7.9% and 5.3%, respectively; matrix effects were negligible and mean recoveries ranged from 95.3 to 111.6%. The limits of quantitation (LOQs) were 0.25 nmol/L for T, A4 and 11OHA4, 0.50 nmol/L for 17OHP, and 0.24 nmol/L for 11KT. No significant change was observed in pre-centrifugation A4 or female T concentrations over 72 h. Significant increases (p < 0.01) in concentrations of 11KT, 17OHP, 11OHA4 and male T were observed after 2, 8, 12 and 24 h, respectively. Conclusions We developed a robust LC-MS/MS assay for the quantitation of total serum T/A4/17OHP/11OHA4 and 11KT. Applying the method to determine pre-analytical stability suggests samples requiring 11KT need separating from the cells within 2 h.

A novel high-throughput assay for the measurement of salivary progesterone by liquid chromatography tandem mass spectrometry.

BACKGROUND: Liquid chromatography tandem mass spectrometry (LC-MS/MS) enables specific and sensitive quantification of steroids with a high throughput. Saliva sampling is advantageous for multisample profiling over longer periods of time, as it is non-invasive, cheap, can be carried out at home and does not require the attendance of clinical personnel. We developed a rapid LC-MS/MS for the measurement of salivary progesterone, frequently assessed as ovulation marker in patients desiring fertility. METHODS: Samples (300 µL) were prepared by supported liquid extraction using dichloromethane and were reconstituted in 40% methanol. Chromatography was performed using a C8 column with a water/methanol gradient containing 0.1% formic acid and 2 mmol/L ammonium acetate. Quantification was performed with a Waters TQ-S mass spectrometer. RESULTS: Total run time was 5.5 min. The lower limit of quantification was 20 pmol/L (1.2 fmol on column). Inter- and intra-assay comparison showed coefficients of variation and bias between measured and nominal concentrations of less than 11%. Mean recovery was 91%. Interference with a large set of natural and synthetic steroids was excluded. The assay was successfully applied to measure progesterone variation during the menstrual cycle ( n = 9) and diurnal variations during luteal phase ( n = 7) in regularly cycling women. DISCUSSION: We present a novel LC-MS/MS assay for the determination of salivary progesterone with high-throughput potential. The applicability of the assay for progesterone profiling during the menstrual cycle is demonstrated.

A combined liquid chromatography tandem mass spectrometry assay for the quantification of urinary oxalate and citrate in patients with nephrolithiasis.

Background Analysis of citrate and oxalate in a 24-h urine sample is important in the screening and monitoring of patients with nephrolithiasis. To streamline the analytical process, it was decided to combine oxalate and citrate and analyse them simultaneously in the same assay. Objective A highly sensitive and specific assay for analysis of urine citrate and oxalate was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) with a simple weak anion exchange solid phase extraction (WAX SPE) clean-up procedure. Method Premixed calibrator/acidified urine (50 µL) was combined with mixed internal standard (13C2 oxalate/citrate-d4) and 5% v/v formic acid in water and passed through a Waters WAX SPE plate. After clean-up steps, the plate was eluted with 5% NH3 in methanol, the eluent was dried down and re-constituted with 100 µL distilled water. Separation was then performed on an HSS T3 2.1 × 50 mm column (Waters, Manchester, UK), flow rate of 0.5 mL/min using a gradient of aqueous and organic mobile phases. We detected multiple reaction monitoring transitions m/z citrate 191.1>110.9, citrate IS 195.1>112.9, oxalate 88.9>60.85, oxalate IS 90.9>61.9 using a Waters TQD in electrospray-negative mode. Results Oxalate and 13C2 oxalate were eluted at 0.29 min; citrate and citrate-d4 were eluted at 0.52 min. Mean recovery was 100% for oxalate and 103% for citrate; lower limit of quantification of oxalate was 60 µmol/L and 50 µmol/L for citrate. Oxalate was linear up to 1388 µmol/L; citrate was linear up to 4762.5 µmol/L. Oxalate was found to be affected by ion suppression (matrix effect: -23 to +65%) but was compensated for by the internal standard used in all cases. The coefficient of variation of the assay in urine for oxalate was <7% for oxalate and 5% for citrate. Discussion We have developed a rapid assay for LC-MS/MS measurement of urinary oxalate and citrate in a routine clinical laboratory. It is simple, reproducible and easy to perform.

Salivary testosterone measurement in women with and without polycystic ovary syndrome.

Clinical and/or biochemical hyperandrogenism is one of the diagnostic criteria for PCOS. An evaluation of the role of salivary testosterone (salT) and androstenedione (salA) for the diagnosis of PCOS was undertaken in a cross sectional study involving 65 women without PCOS and 110 women with PCOS fulfilling all 3 diagnostic Rotterdam criteria. Serum and salivary androgen measurements were determined by LC-MS/MS. salT and salA were significantly elevated in PCOS compared to controls (P < 001). No androgen marker was more predictive than another using ROC curves, but multiple logistic regression suggested salT was more predictive than free androgen index (FAI) (p < 0.01). The combination of salT or FAI identified 100% of PCOS women. PCOS women with both biochemical and clinical hyperandrogenism as opposed to clinical hyperandrogenism alone showed a metabolic phenotype (p < 0.05) and insulin resistance (p < 0.001). PCOS patients with an isolated elevated FAI showed increased insulin resistance compared to those with an isolated salT (P < 0.05). salT appeared to be at least as predictive as FAI for the diagnosis of the classical PCOS phenotype, and the combination of salT or FAI identified 100% of PCOS patients. This suggests that salT measurement by LC-MS/MS holds the promise of complementing existing laboratory tests as a means of assessing hyperandrogenemia.

Serum and plasma 5-hydroxyindoleacetic acid as an alternative to 24-h urine 5-hydroxyindoleacetic acid measurement.

BACKGROUND: Neuroendocrine tumours are slow growing tumours known to secrete a variety of vasoactive peptides which give rise to symptoms of the carcinoid syndrome. The diagnosis and monitoring of patients with neuroendocrine tumours is undertaken in many centres using 24 h urinary measurement of 5-hydroxyindoleacetic acid. However, 5-hydroxyindoleacetic acid can also be quantified in plasma and serum. METHODS: We measured 5-hydroxyindoleacetic acid concentration in 134 paired EDTA plasma and urine samples from 108 patients with known neuroendocrine tumours and 26 healthy volunteers. We also compared 5-hydroxyindoleacetic acid concentrations in paired serum and plasma samples (n = 63), then analysed paired urine and serum samples (n = 97). Furthermore, we examined the impact of renal impairment on serum 5-hydroxyindoleacetic acid by analysing 5-hydroxyindoleacetic acid in patients without neuroendocrine tumours in different stages of chronic kidney disease, as indicated by the estimated glomerular filtration rate. RESULTS: Plasma and urine 5-hydroxyindoleacetic acid had very similar diagnostic sensitivities and specificities, with areas under the curve on ROC analysis of 0.917 and 0.920, respectively. Serum and plasma 5-hydroxyindoleacetic acid values showed good correlation but serum results demonstrated a positive bias, indicating the necessity for different serum and plasma reference intervals. There was an inverse correlation between estimated glomerular filtration rate and serum 5-hydroxyindoleacetic acid concentration, with 5-hydroxyindoleacetic acid increasing once the estimated glomerular filtration rate falls below 60 mL/min/1.73 m(2). CONCLUSION: The measurement of both serum and plasma 5-hydroxyindoleacetic acid can be used for the diagnosis and monitoring of patients with neuroendocrine tumours. Provided renal function is taken into consideration, either of these tests should be incorporated into standard practice as an alternative assay to urinary 5-hydroxyindoleacetic acid.

A novel method for the measurement of plasma metanephrines using online solid phase extraction-liquid chromatography tandem mass spectrometry.

BACKGROUND: Measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine is useful in the diagnosis of phaeochromocytomas, but many assays require a large volume of plasma due to poor assay sensitivity, and often require lengthy sample preparation. Our aim was to develop a method for measurement of plasma metanephrines using a small sample volume with minimal hands-on preparation. METHODS: Samples were deproteinised using 10 K spin filters prior to online solid phase extraction using a Waters Acquity UPLC Online SPE Manager (Waters, Manchester, UK) coupled to a Waters Xevo TQ-S mass spectrometer (Waters, Manchester, UK). The assay was validated and results compared to a previously published method. RESULTS: We achieved a limit of quantification of 37.5 pmol/L for metanephrine and 3-methoxytyramine and 75 pmol/L for normetanephrine using only 150 µL of sample. The assay was linear up to 30,000 pmol/L for all analytes and in a method comparison study results showed good agreement with a previously published LC-MS/MS assay. CONCLUSIONS: We have developed a simple method for measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine using only 150 µL of sample. There is minimal hands-on sample preparation required and the assay is suitable for routine use in a clinical laboratory.

Liquid chromatography tandem mass spectrometry in the clinical laboratory.

Clinical laboratory medicine has seen the introduction and evolution of liquid chromatography tandem mass spectrometry in routine clinical laboratories over the last 10-15 years. There still exists a wide diversity of assays from very esoteric and highly specialist manual assays to more simplified kit-based assays. The technology is not static as manufacturers are continually making improvements. Mass spectrometry is now commonly used in several areas of diagnostics including therapeutic drug monitoring, toxicology, endocrinology, paediatrics and microbiology. Some of the most high throughput analyses or common analytes include vitamin D, immunosuppressant monitoring, androgen measurement and newborn screening. It also offers flexibility for the measurement of analytes in a variety of different matrices which would prove difficult with immunoassays. Unlike immunoassays or high-pressure liquid chromatography assays using ultraviolet or fluorescence detection, mass spectrometry offers better specificity and reduced interferences if attention is paid to potential isobaric compounds. Furthermore, multiplexing, which enables multiple analytes to be measured with the same volume of serum is advantageous, and the requirement for large sample volumes is decreasing as instrument sensitivity increases. There are many emerging applications in the literature. Using mass spectrometry to identify novel isoforms or modified peptides is possible as is quantification of proteins and peptides, with or without protein digests. Future developments by the manufacturers may also include mechanisms to improve the throughput of samples and strategies to decrease the level of skill required by the operators.

A widely applicable plasma renin activity assay by LC-MS/MS with offline solid phase extraction.

BACKGROUND: The measurement of plasma renin activity using LC-MS/MS is an attractive alternative to radioimmunoassay techniques. A published method for renin activity by LC-MS/MS uses equipment that is not available in all LC-MS/MS laboratories. Here, we present an offline modification to allow users of LC-MS/MS to perform this analysis without specialist equipment. METHODS: Samples were prepared in duplicate and incubated for 6.5 h and 24 h. Solid phase extraction was performed offline using Waters Oasis MAX ion-exchange 96-well plate. A method comparison was performed between this assay and a previously published assay using on-line solid phase extraction. RESULTS: The offline method for plasma rennin activity gave similar results to the on-line method across the concentration range. Analytical performance was also found to be comparable and the use of a 24 h incubation for low samples was also deemed unnecessary. DISCUSSION: The method described is an acceptable alternative to a previously published assay which does not require the use of highly specialist equipment and will be applicable to the majority of LC-MS/MS users.

Therapeutic drug monitoring of ciclosporin A and tacrolimus in heart lung transplant patients using dried blood spots.

BACKGROUND: Therapeutic drug monitoring of ciclosporin A (CsA) and tacrolimus is traditionally performed using venous whole blood sampling. A number of reports have described development of ultra high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) methods for the quantitation of CsA and tacrolimus from dried blood spots (DBS), which may offer a convenient alternative. As yet, no such reports have validated this methodology using fingerprick capillary DBS samples collected from transplant patients. METHODS: Capillary fingerprick DBS were collected from heart and lung transplant patients in a specialist cardiothoracic transplant centre. We utilized our previously published method for the extraction and simultaneous quantitation of CsA and tacrolimus from DBS using UPLC-MS/MS. Drug concentrations measured from DBS were compared to concentrations measured in venous whole blood by our routine clinical UPLC-MS/MS assay. RESULTS: In total, 91 heart or lung transplant patients were enrolled onto the study; 46 patients were on CsA therapy and 45 on tacrolimus therapy. Passing-Bablock analysis demonstrated excellent agreement between capillary fingerprick DBS samples and venous whole blood samples. There was a mean positive bias of 2.6 µg/L (95% confidence interval (CI) -2.2 to 7.5 µg/L) for CsA (n = 45) and mean negative bias of -0.7 µg/L (95% CI -1.1 to -0.3 µg/L) for tacrolimus (n = 42). CONCLUSIONS: We demonstrate utility of DBS for serial monitoring of CsA and tacrolimus using UPLC-MS/MS in heart and lung transplant patients. This may offer significant advantages for these patients including the ability to take capillary DBS samples in the community prior to clinic visits.

The association of a panel of biomarkers with the presence and severity of carcinoid heart disease: a cross-sectional study.

PURPOSE: Metastatic neuroendocrine tumors secrete serotonin and other vasoactive substances that are responsible for carcinoid syndrome and carcinoid heart disease. We sought to evaluate the discriminatory utility of diagnostic biomarkers in determining the presence and severity of carcinoid heart disease in patients with metastatic neuroendocrine tumors. PATIENTS AND METHODS: A cross-sectional study of patients with neuroendocrine tumors with documented liver metastases and/or carcinoid syndrome between April 2009-October 2012 in 5 tertiary referral centers. Serum was analyzed for Chromogranin A, Chromogranin B and N-terminal pro Brain Natriuretic Peptide (NT-proBNP). Plasma was analyzed for Neurokinin A and 5-Hydroxyindoleacetic acid (5HIAA). Echocardiography was used to determine the presence and severity of carcinoid heart disease. Non-parametric receiver operating characteristic curves were constructed for biomarkers, and the area under the curve determined. The severity of cardiac involvement was correlated with the concentration of each biomarker. RESULTS: A total of 187 patients were identified of whom 37 (20%) had carcinoid heart disease. Significantly higher median values of all biomarkers were found in the patients with cardiac involvement. NT-proBNP and plasma 5HIAA had the highest areas under the curve for the prediction of carcinoid heart disease [NT-proBNP 0.82 (95% confidence interval 0.74-0.90, p<0.0001) and 5HIAA 0.85 (95% confidence interval 0.78-0.92, p<0.0001]. NT-proBNP was moderately correlated (r = 0.48, p<0.001) whereas plasma 5HIAA was only weakly correlated (r = 0.34, p<0.001) with the echocardiographic severity score. CONCLUSION: NT-proBNP and plasma 5HIAA are both sensitive and specific biomarkers for the presence of carcinoid heart disease whereas only NT-proBNP is moderately correlated with disease severity.

Development of a rapid assay for the analysis of serum cortisol and its implementation into a routine service laboratory.

BACKGROUND: LC-MS/MS is rapidly becoming the technology of choice for measuring steroid hormones. We have developed a rapid LC-MS/MS assay for the routine analysis of serum cortisol. We have used this assay to investigate the effects of gender and exogenous steroid interference on the immunoassay measurement of serum cortisol. METHODS: Zinc sulphate (40 µL) was added to 20 µL of sample. This was vortexed for 10 s followed by the addition of 100 µL of internal standard in methanol. Following mixing and centrifugation, 10 µL of sample was injected into an Acquity LC system coupled to a Quattro Premier tandem mass spectrometer. Serum samples (n = 149) were analysed by LC-MS/MS and two commercial immunoassays. Results were then compared for all samples and for gender differences. A further set of serum samples (n = 171) was analysed by the LC-MS/MS assay and a GC-MS assay. RESULTS: Cortisol had a retention time of 0.98 min and the assay had an injection-to-injection time of 2.6 min per sample. Mean recovery was 99% and mean CV was 8%. The immunoassays gave comparisons of: Roche = 1.23 × LC-MS/MS -1.12 nmol/L and Abbott = 0.94 × LC-MS/MS + 11.97. The comparison with GC-MS showed LC-MS/MS = 1.11 × GC-MS - 22.90. DISCUSSION: We have developed an LC-MS/MS assay for serum cortisol analysis that is suitable for routine clinical use and has been in use in our laboratory for 12 months. The availability of this assay will give more reliable results in patients receiving exogenous steroid therapy.