Development and performance evaluation of a tandem mass spectrometry assay for 4 adrenal steroids

Simultaneous determination of endogenous steroid hormones in human and animal plasma and serum by liquid or gas chromatography coupled to tandem mass spectrometry

Analytical methodologies based on liquid or gas chromatography coupled to tandem mass spectrometry for the simultaneous determination of two or more endogenous steroid hormones in human and animal plasma and serum has received increased attention the last few years. Especially in the clinical setting steroid profiling is of major importance in disease diagnostics. This paper discusses recent findings in such multi-steroid hormone procedures published from 2001 to 2012. The aim was to elucidate possible relationships between chosen analytical technique and the obtained analyte sensitivity for endogenous steroid hormones. By evaluating the success, at which the currently applied techniques have been utilized, more general knowledge on the field is provided. Furthermore the evaluation provides directions in which future studies may be interesting to conduct.

Tandem mass spectrometry in hormone measurement

Mass spectrometry methods have the potential to measure different hormones during the same analysis and have improved specificity and a wide analytical range compared with many immunoassay methods. Increasingly in clinical laboratories liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays are replacing immunoassays for the routine measurement of testosterone, 17-hydroxyprogesterone, and other steroid hormones. Reference LC-MS/MS methods for steroid, thyroid, and peptide hormones are being used for assessment of the performance and calibration of commercial immunoassays. In this chapter, the general principles of tandem mass spectrometry and examples of hormone assays are described.

Protein and steroid profiles in follicular fluid after ovarian hyperstimulation as potential biomarkers of IVF outcome

Controlled ovarian hyperstimulation is performed to assist with generation of multiple mature oocytes for use in in vitro fertilization (IVF). The goal of our study was to evaluate differences in protein and steroid profiles in ovarian follicular fluid (hFF) samples obtained during oocyte retrieval from women undergoing IVF treatment and to identify physiological pathways associated with the proteins. The hFF samples were depleted of abundant proteins, fractionated by ultrafiltration, digested, and analyzed by nano-LC-QTOF. Concentrations of 15 endogenous steroids were determined in the samples using LC-MS/MS methods. The total number of proteins identified in the samples was 75, of which 4, 7, and 2 were unique to the samples from women with viable pregnancy, miscarriage, and no pregnancy, respectively. Identified proteins were associated with the acute response signaling, coagulation system, intrinsic and extrinsic prothrombin activation, complement system, neuroprotective role of THOP1, FXR/RXR activation, role of tissue factor, and growth hormone pathways. A greater number of proteins associated with biosynthesis was found in hFF samples corresponding to the oocytes resulting in pregnancy. The abundance of seven proteins was found to be associated with steroidogenesis. The obtained data will contribute to better understanding of the pathogenesis and development of noninvasive markers for assessment of oocytes viability.

Patterns of endogenous steroids in apathetic refugee children are compatible with long-term stress

Background

During the last few years, a number of children of asylum applicants in Sweden developed an apathetic or unconscious state. The syndrome was perceived as new, and various explanations were advanced such as factitious disorder, intoxication, or stress. Considering a potential association between traumatic stress and regulation of steroids biosynthesis, this study explored whether changes in concentrations of endogenous steroids were associated with the above syndrome.

Methods

Eleven children were recruited in the study. Concentrations of steroids in blood samples were determined using high sensitivity liquid chromatography tandem mass spectrometry methods. Symptoms were assessed with a clinical rating scale developed for the study. Steroid concentrations were measured at the entry into study and after recovery; and concentrations were evaluated for the association with the symptoms in apathetic children.

Results

Cortisol and cortisone concentrations at baseline were negatively associated with duration of the symptoms from entry into the study to clinical recovery. Higher concentrations of pregnanes (pregnenolone, 17-OH-pregnenolone, and dehydroepiandrosterone) were observed in the symptomatic state and the concentrations decreased after the recovery.

Conclusions

Pattern of low cortisol concentrations found in apathetic children is consistent with long-term stress. An increase of upstream steroid metabolites (pregnanes) was found to be associated with the symptomatic state.

Cellular pregnenolone esterification by acyl-CoA:cholesterol acyltransferase

Pregnenolone (PREG) can be converted to PREG esters (PE) by the plasma enzyme lecithin: cholesterol acyltransferase (LCAT), and by other enzyme(s) with unknown identity. Acyl-CoA:cholesterol acyltransferase 1 and 2 (ACAT1 and ACAT2) convert various sterols to steryl esters; their activities are activated by cholesterol. PREG is a sterol-like molecule, with 3-β-hydroxy moiety at steroid ring A, but with much shorter side chain at steroid ring D. Here we show that without cholesterol, PREG is a poor ACAT substrate; with cholesterol, the V(max) for PREG esterification increases by 100-fold. The binding affinity of ACAT1 for PREG is 30-50-fold stronger than that for cholesterol; however, PREG is only a substrate but not an activator, while cholesterol is both a substrate and an activator. These results indicate that the sterol substrate site in ACAT1 does not involve significant sterol-phospholipid interaction, while the sterol activator site does. Studies utilizing small molecule ACAT inhibitors show that ACAT plays a key role in PREG esterification in various cell types examined. Mice lacking ACAT1 or ACAT2 do not have decreased PREG ester contents in adrenals, nor do they have altered levels of the three major secreted adrenal steroids in serum. Mice lacking LCAT have decreased levels of PREG esters in the adrenals. These results suggest LCAT along with ACAT1/ACAT2 contribute to control pregnenolone ester content in different cell types and tissues.

Challenges and benefits of endogenous steroid analysis by LC–MS/MS

Quantification of endogenous hormonal steroids and their precursors is essential for diagnosing a wide range of endocrine disorders. Historically, these analyses have been carried out using immunoassay, but such methods are problematic, especially for low-concentration analytes, due to assay interference by other endogenous steroids. MS offers improved specificity over immunoassay and can be highly sensitive. GC–MS, with use of stable isotopically labeled internal standards, is considered the ‘gold standard’ method for serum steroid analysis. GC–MS is the method of choice for profiling steroid metabolites in urine, but these techniques are not appropriate for routine use in clinical laboratories owing to a need for extensive sample preparation, as well as analytical expertise. LC–MS/MS compares well to GC–MS in terms of accuracy, precision and sensitivity, but allows simplified sample preparation. While most publications have featured only one or a limited number of steroids, we consider that steroid paneling (which we propose as the preferred term for multitargeted steroid analysis) has great potential to enable clinicians to make a definitive diagnosis. It is adaptable for use in a number of matrices, including serum, saliva and dried blood spots. However, LC–MS/MS-based steroid analysis is not straightforward, and understanding the chemical and analytical processes involved is essential for implementation of a robust clinical service. This article discusses specific challenges in the measurement of endogenous steroids using LC–MS/MS, and provides examples of the benefits it offers.

Fast and sensitive liquid chromatography-mass spectrometry assay for seven androgenic and progestagenic steroids in human serum

A fast and sensitive LC-MS/MS method for the quantitative analysis of seven steroid hormones in 150 μl of human serum was developed and validated. The following compounds were included: 17α-hydroxypregnenolone, 17α-hydroxyprogesterone, androstenedione, dehydroepiandrosterone, testosterone, pregnenolone, and progesterone. Individual stable isotope-labeled analogues were used as internal standards. Sample preparation was performed by liquid-liquid extraction, followed by oxime derivatization to improve the ionization efficiency of the analytes. In contrast to the common derivatization-based methods, the reaction was incorporated into the sample preparation process and the only additional step due to the derivatization was a short heating of the autosampler vials before the sample injection. Chromatographic separation was achieved on a reversed-phase column using a methanol-water gradient. For the analyte detection, a triple quadrupole instrument with electrospray ionization was used. Total run time was 7.0 min and the lower limits of quantification were in the range of 0.03-0.34 nM (0.01-0.10 ng/ml), depending on the analyte. The method was validated using human serum samples from both sexes and applied for the serum steroid profiling of endometriosis patients.

Principles and clinical applications of liquid chromatography - tandem mass spectrometry for the determination of adrenal and gonadal steroid hormones

Liquid-chromatography - tandem mass spectrometry (LC-MS/MS) is becoming the method of choice for clinical steroid analysis. In most instances, it has the advantage of higher sensitivity, better reproducibility and greater specificity than commercial immunoassay techniques. The method requires only minimal sample preparation and a small sample volume. Furthermore, it has the potential to analyze multiple steroids simultaneously. Modern instruments guarantee high throughput, allowing an affordable price for the individual assay. All this makes LC-MS/MS an attractive method for use in a clinical setting. Reliable reference ranges for the detected analytes are the pre-requisite for their clinical use. If these are available, LC-MS/MS can find application in congenital disorders of steroid metabolism, such as congenital adrenal hyperplasia, disorders of sex development and disorders of salt homeostasis, as well as in acquired disorders of steroid metabolism, such as primary aldosteronism, Cushing's disease, Addison's disease, and hyperandrogenemia, as well as in psychiatric disease states such as depression or anxiety disorders. The principles of LC-MS/MS for steroid measurement, the pros and cons of LC-MS/MS compared with conventional immunoassays and the possible applications in clinical routine, with a special focus on pediatric endocrinology needs, are discussed here.

Confirmation of congenital adrenal hyperplasia by adrenal steroid profiling of filter paper dried blood samples using ultra-performance liquid chromatography-tandem mass spectrometry

BACKGROUND

The specificity of screening for congenital adrenal hyperplasia by direct measurement of 17-hydroxyprogesterone in filter paper dried blood spot samples by immunoassay is low and has a high false-positive rate. In order to reduce the false-positive rate of this test, we developed a rapid, robust, specific confirmatory procedure in which cortisol, 4-androstene-3,17-dione and 17-hydroxyprogesterone were measured simultaneously by ultra-performance liquid chromatography-tandem mass spectrometry.

METHODS

After extraction, samples were analysed by ultra-performance liquid chromatography-tandem mass spectrometry and 17-hydroxyprogesterone was quantified accurately. Other steroids were determined using stable deuterated internal standards. In total, 25 patient blood spot samples and 92 control samples were analysed.

RESULTS

The assay was linear for 17-hydroxyprogesterone, with a coefficient of determination >0.997 and imprecision ≤ 6.5%. An upper limit of normal for 17-hydroxyprogester-one of 4.45 nmol/L was established by analysing a cohort of samples from unaffected newborns. In addition, a cut-off of 3.5 for the peak areas ratio (17-hydroxyprogesterone+4-androstene-3,17-dione)/cortisol, allows confirmation of the affected steroidogenic enzyme.

CONCLUSIONS

A high throughput method for the detection of steroids related to congenital adrenal hyperplasia has been developed, allowing the false-positive rate associated with screening for 17-hydroxyprogesterone by immunoassay to be determined.

Serum steroid profiling by isotopic dilution-liquid chromatography-mass spectrometry: comparison with current immunoassays and reference intervals in healthy adults

BACKGROUND

The simultaneous, rapid and reliable measurement of a wide steroid panel is a powerful tool to unravel physiological and pathological hormone status. Clinical laboratories are currently dominated by high-throughput immunoassays, but these methods lack specificity due to cross-reactivity and matrix interferences. We developed and validated an isotopic dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) method for the simultaneous measurement of cortisol, corticosterone, 11deoxycortisol, androstenedione, deoxycorticosterone (DOC), testosterone, 17OHprogesterone, dehydroepiandrosterone (DHEA) and progesterone in serum, and compared it to routine immunoassays employed in our laboratory. We also established adult reference intervals in 416 healthy subjects.

METHODS

0.9 ml of serum were spiked with labelled internal standards (IS) and extracted on C18 cartridges. Eluate was injected into a two-dimensional LC-system, purified in a perfusion column and separated on a C8 column during a 21 min gradient run. Analytes were revealed by atmospheric pressure chemical ionization (APCI) followed by multiple reaction monitoring (MRM) analysis.

RESULTS

Of the four immunoassays compared with the ID-LC-MS/MS method, only the results of ElecsysE170 for cortisol, testosterone in males and progesterone>1 ng/ml were in agreement with ID-LC-MS/MS. ElecsysE170 for testosterone in females and progesterone<1 ng/ml, Immulite2000 for androstenedione, DSL-9000 for DHEA and 17OHP Bridge for 17OHprogesterone, respectively, showed poor agreement. Reference intervals and steroid age and fertility related fluctuations were established.

CONCLUSION

Our ID-LC-MS/MS method proved to be reliable and sensitive in revealing steroid circulating concentrations in adults and in highlighting the limits of routine immunoassays at low concentrations.

Total testosterone assays in women with polycystic ovary syndrome: precision and correlation with hirsutism

CONTEXT

There is no standardized assay of testosterone in women. Liquid chromatography mass spectrometry (LC/MS) has been proposed as the preferable assay by an Endocrine Society Position Statement.

OBJECTIVE

The aim was to compare assay results from a direct RIA with two LC/MS.

DESIGN AND SETTING

We conducted a blinded laboratory study including masked duplicate samples at three laboratories--two academic (University of Virginia, RIA; and Mayo Clinic, LC/MS) and one commercial (Quest, LC/MS).

PARTICIPANTS AND INTERVENTIONS

Baseline testosterone levels from 596 women with PCOS who participated in a large, multicenter, randomized controlled infertility trial performed at academic health centers in the United States were run by varying assays, and results were compared.

MAIN OUTCOME MEASURE

We measured assay precision and correlation and baseline Ferriman-Gallwey hirsutism scores.

RESULTS

Median testosterone levels were highest with RIA. The correlations between the blinded samples that were run in duplicate were comparable. The correlation coefficient (CC) between LC/MS at Quest and Mayo was 0.83 [95% confidence interval (CI), 0.80-0.85], between RIA and LC/MS at Mayo was 0.79 (95% CI, 0.76-0.82), and between RIA and LC/MS at Quest was 0.67 (95% CI, 0.63-0.72). Interassay variation was highest at the lower levels of total testosterone (≤50 ng/dl). The CC for Quest LC/MS was significantly different from those derived from the other assays. We found similar correlations between total testosterone levels and hirsutism score with the RIA (CC=0.24), LC/MS at Mayo (CC=0.15), or Quest (CC=0.17).

CONCLUSIONS

A testosterone RIA is comparable to LC/MS assays. There is significant variability between LC/MS assays and poor precision with all assays at low testosterone levels.

Congenital adrenal hyperplasia due to steroid 21-hydroxylase deficiency: an Endocrine Society clinical practice guideline

OBJECTIVE

We developed clinical practice guidelines for congenital adrenal hyperplasia (CAH).

PARTICIPANTS

The Task Force included a chair, selected by The Endocrine Society Clinical Guidelines Subcommittee (CGS), ten additional clinicians experienced in treating CAH, a methodologist, and a medical writer. Additional experts were also consulted. The authors received no corporate funding or remuneration.

CONSENSUS PROCESS

Consensus was guided by systematic reviews of evidence and discussions. The guidelines were reviewed and approved sequentially by The Endocrine Society's CGS and Clinical Affairs Core Committee, members responding to a web posting, and The Endocrine Society Council. At each stage, the Task Force incorporated changes in response to written comments.

CONCLUSIONS

We recommend universal newborn screening for severe steroid 21-hydroxylase deficiency followed by confirmatory tests. We recommend that prenatal treatment of CAH continue to be regarded as experimental. The diagnosis rests on clinical and hormonal data; genotyping is reserved for equivocal cases and genetic counseling. Glucocorticoid dosage should be minimized to avoid iatrogenic Cushing's syndrome. Mineralocorticoids and, in infants, supplemental sodium are recommended in classic CAH patients. We recommend against the routine use of experimental therapies to promote growth and delay puberty; we suggest patients avoid adrenalectomy. Surgical guidelines emphasize early single-stage genital repair for severely virilized girls, performed by experienced surgeons. Clinicians should consider patients' quality of life, consulting mental health professionals as appropriate. At the transition to adulthood, we recommend monitoring for potential complications of CAH. Finally, we recommend judicious use of medication during pregnancy and in symptomatic patients with nonclassic CAH.

Determination of naturally occurring progestogens in bovine milk as their oxime derivatives using high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

BACKGROUND

Hormones and hormone-like substances which are present in the environment have been repeatedly accused of being the cause of most endocrine disruption. However, the possible role of endogenous hormones in food of animal origin deserves to be discussed as well. The relation between steroid hormones and several human health problems has been previously reported, such as prostate and breast cancer, perturbation of human reproduction and endocrine disruption on humans and wildlife. This research is particularly concerned with cow's milk, which contains a considerable amount of sex hormones.

RESULTS

A liquid chromatography-tandem mass spectrometry method has been developed for the simultaneous detection and quantification of four naturally occurring steroid hormones in commercial bovine milk (pregnenolone (P5), progesterone (P4), 17-hydroxypregnenolone (17-OHP5), 17-hydroxyprogesterone (P4)). Oxime derivatives of steroids were analyzed in positive ionization and multiple reaction monitoring mode. Methodology has been validated according to Decision 2002/657/EC criteria.

CONCLUSION

This method has been successfully used in real samples. It is fast and easy-handling and provides a useful tool for the assessment of progestogens in bovine milk.

Preclinical challenges in steroid analysis of human samples

Preclinical challenges in the analysis of steroid hormones are primarily determined by biological factors involved in the physiology and pathophysiology of hormone secretion. Major biologically influencing factors like age, sex, pubertal stage, pregnancy, phase of the menstruation, and diurnal rhythm have to be considered in the definition of reference ranges for steroids and their clinical interpretation. Hitherto, in clinical routine laboratories steroids were mainly determined by direct immunoassays applied on automated platforms, which are simple, rapid and cheap if a high number of samples are measured. However, technical factors like cross-reactivity of related steroid metabolites or limited analytical ranges have to be taken in account and may impair accuracy and precision of these direct methods. The actual development of mass spectrometry based analytical platforms for the determination of single steroid or steroid patterns seems to be an alternative analytical approach combining multi-parametric analysis, high sensitivity and specificity as well simple sample pre-treatment, robustness and low running costs for steroid analysis. This short review will give an overview about biological influencing factors and technical disturbing factors of routinely used immunoassay for the analysis of steroids. The application of LC-MS/MS as an alternative routine high-throughput platform for steroid analysis and its perspective role in the standardization and harmonisation of steroid measurements in clinical routine application will be discussed.

Steroid measurement with LC-MS/MS. Application examples in pediatrics

The correct measurement of steroids is vital for the diagnosis of congenital adrenal hyperplasia (CAH), apparent mineralocorticoid excess, familial hyperaldosteronism type I, primary aldosteronism, Cushing's disease, adrenal insufficiency, etc. Steroid diagnostics also plays an important role in disorders of sexual differentiation and gonadal function. Steroid metabolism is involved in evaluations for precocious puberty, premature thelarche, and polycystic-ovary disease. Finally, the hypothalamo-pituitary-adrenal (HPA) axis is considered to be one of the major systems involved in fetal programming or in stress regulation. Most methods for the determination of steroid hormones are based on immunoassays, which are rapid and easy to perform. However, the reliability of several steroid immunoassays has been shown to be questionable because of the lack of specificity and of matrix effects. Immunological methods, especially direct assays, often overestimate true steroid values. Patient follow-up over time or between laboratories, as well as longitudinal studies, are therefore extremely difficult. This is of particular importance in pediatrics. Liquid chromatography triple quadrupole mass spectrometry (LC-MS/MS) is an increasingly common tool in the clinical laboratory and has the potential to overcome the limitations of immunoassays. LC-MS/MS affords the specificity, imprecision, and limits of quantification necessary for the reliable measurement of steroids, expanding diagnostic capabilities. In addition to the high throughput, the method requires minimal sample preparation and a small sample volume. All these features make it an attractive method to use in a clinical setting. Moreover, LC-MS/MS has the advantage that a spectrum of steroid hormones can be measured simultaneously. Steroid profiling is a very effective method for distinguishing almost all steroid-related disorders. It allows accurate diagnosis and is very useful in many clinical situations. Steroid profiles open up new vistas. The applicability for clinical samples and questions in pediatric endocrinology will be discussed.

Liquid chromatography-tandem mass spectrometry assay for androstenedione, dehydroepiandrosterone, and testosterone with pediatric and adult reference intervals

BACKGROUND

Measurement of serum androgens is important in adult, geriatric, pediatric endocrinology, and oncology patients. We developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous measurement of androstenedione, dehydroepiandrosterone (DHEA), and testosterone in these patients.

METHODS

We spiked 200 muL of serum or plasma with isotope-labeled internal standards and performed extraction with methyl t-butyl ether. We then derivatized the extracts with hydroxylamine and analyzed them by LC-MS/MS using a 2-dimensional chromatographic separation with a 3.5-min analysis time.

RESULTS

Total imprecision for each analyte was <11.2%. Limits of quantification were 10, 50, and 10 ng/L for androstenedione, DHEA, and testosterone, respectively. Reference intervals were established for children (age 6 months to 17 years), men, and women. Androstenedione and DHEA concentrations were lowest in 2- to 3-year-old children. Adult concentrations were achieved in girls at Tanner stage 3 and in boys at Tanner stage 4-5. In premenopausal and (postmenopausal) women the median concentrations of androstenedione, DHEA, and testosterone were 810 (360), 3000 (1670), 270 (180) ng/L, respectively. In postmenopausal women, concentrations of testosterone were age independent, whereas androstenedione and DHEA concentrations decreased with age. In men the median concentrations of androstenedione, DHEA, and testosterone were 440, 2000, and 3700 ng/L, respectively. In men older than 40 years, median concentrations decreased at rates of 5%, 10%, and 20% per decade for androstenedione, DHEA, and testosterone, respectively.

CONCLUSIONS

This LC-MS/MS method has the required lower limit of quantification and specificity for analysis of endogenous concentrations of androgens in all groups studied. Reference intervals were established for healthy children and adults.

Liquid chromatography-tandem mass spectrometry applications in endocrinology

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been recognized as a primary methodology for the accurate analysis of endogenous steroid hormones in biological samples. This review focuses on the use of LC-MS/MS in clinical laboratories to assist with the diagnosis of diverse groups of endocrine and metabolic diseases. Described analytical methods use on-line and off-line sample preparation and analytical derivatization to enhance analytical sensitivity, specificity, and clinical utility. Advantages of LC-MS/MS as an analytical technique include high specificity, possibility to simultaneously measure multiple analytes, and the ability to assess the specificity of the analysis in every sample. All described analytical methods were extensively validated, utilized in routine diagnostic practice, and were applied in a number of clinical and epidemiological studies, including a study of the steroidogenesis in ovarian follicles.

Endogenous steroids measured by high-specificity liquid chromatography-tandem mass spectrometry and prevalent cardiovascular disease in 70-year-old men and women

CONTEXT

There is a need for increased knowledge about endogenous sex hormone levels and clinical outcomes of risk/benefit. Immunoassays have poor specificity to reliably measure low steroid concentrations in elderly.

OBJECTIVE

The objective of the study was to evaluate plasma steroid concentrations with regard to prevalent cardiovascular disease (CVD) in elderly, using mass spectrometry.

SETTING

The study was conducted at a university hospital research unit.

DESIGN AND METHODS

Plasma samples were analyzed from 202 70-yr-olds as part of a large population-based study, Prospective Investigation of the Vasculature in Uppsala Seniors. Twenty-eight of these had prevalent CVD. Eleven steroids were quantified, using liquid chromatography-tandem mass spectrometry. Women with current/previous menopausal hormone therapy (n = 35) were excluded.

RESULTS

Men without prevalent CVD had higher plasma 17beta-estradiol (E2), compared with women. Men with prevalent CVD, compared with those without, had lower 17-hydroxypregnenolone (17OHPregn), 17-hydroxyprogesterone, and higher estrone/androstenedione and E2/testosterone (T) (aromatase activity). Women with prevalent CVD had lower pregnenolone, 17OHPregn, and dehydroepiandrosterone (DHEA) but higher DHEA/17OHPregn, androstenedione/DHEA, E2/T, E2/estrone, and E2/SHBG. The aromatase index, E2/T, was higher for prevalent CVD in both sexes. Adjustment for statin use, smoking, and body mass index yielded additional significant differences in men, whereas some were lost in women. Logistic regression indicated strong associations between prevalent CVD and low 17OHPregn, adjusted odds ratio of 0.18, 95% confidence interval (0.06-0.61); P = 0.006, in women and low 17-hydroxyprogesterone, 0.45 (0.25-0.80); P = 0.007 in men, most likely caused by increased throughput (consumption) toward estrogen synthesis.

CONCLUSIONS

Prevalent CVD was associated with indications of lower androgen precursors, increased aromatase activity, and higher estrogen levels in both sexes. Results might represent an endogenous response to a condition of developing atherosclerosis, rather than a causative relationship. Furthermore studies are needed.

Holistic management of DSD

Disorder of sex development (DSD) presents a unique challenge, both diagnostically and in terms of acute and longer-term management. These are relatively rare conditions usually requiring a multidisciplinary approach from the outset and the involvement of a tertiary centre for assessment and management recommendations. This article describes the structure of the multidisciplinary team (MDT) at our centre, with contributions from key members of the team regarding their individual roles. The focus is on the newborn referred for assessment of ambiguous genitalia, rather than on individuals who present in the adolescent period or at other times, although the same MDT involvement is likely to be required. The approach to the initial assessment and management is discussed and the subsequent diagnosis and follow-up presented, with emphasis on the importance of careful transition and long-term support.

High sensitivity measurement of estrone and estradiol in serum and plasma using LC-MS/MS

Measurement of low concentrations of estrogens, encountered in pre-pubertal children, men, and postmenopausal women, is important for numerous clinical applications. We describe a method for high sensitivity analysis of estrogens that uses two-dimensional chromatographic separation and tandem mass spectrometry detection. Aliquots of serum or plasma samples are combined with stable isotope-labeled internal standard and estrogens are extracted with methyl t-butyl ether. The solvent is evaporated, estrogens derivatized to form dansyl derivatives, and the samples are analyzed. Quantitation is performed using triple quadrupole mass spectrometer equipped with electrospray ion source using positive ion mode ionization and multiple reaction monitoring acquisition.

Liquid chromatography-tandem mass spectrometry analysis of urinary fluticasone propionate-17beta-carboxylic acid for monitoring compliance with inhaled-fluticasone propionate therapy

BACKGROUND

Inhaled corticosteroids including fluticasone propionate (FP) are the most effective treatment for persistent-asthma. Noncompliance ranging from 20% to 80% of treated patients is associated with substantial health care costs, morbidity and fatalities. A noninvasive test to assess FP treatment compliance is needed. The major metabolite of FP is FP-17beta-carboxylic acid (FP17betaCA) and is excreted in urine. This study demonstrates the development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay to measure FP17betaCA in urine and evaluation of FP17betaCA urinary elimination.

EXPERIMENTAL

Fluorometholone was used as the internal standard. After acetonitrile precipitation, samples were extracted with dichloromethane, washed and dried. Reconstituted extract (60 microL) was subjected to reversed-phase chromatography and positive-ion mode LC-MS/MS analysis. Assay precision, linearity, recovery and sample stability were determined. Elimination evaluation included measurement of FP17betaCA in urine collected daily from human subjects before (day 1), during treatment (days 2-5; dose FP-110 microg 2 puffs/day), and following cessation of FP therapy (days 6-14; n=4).

RESULTS

Linear range of the FP17betaCA assay was 10.3-9510pg/mL. Limit of quantitation (LOQ) was 10.3 pg/mL and recovery ranged from 85.8% to 111.9%. Inter-assay CVs were 7.4-12.0% for FP17betaCA concentrations of 11.1-5117 pg/mL. Urine FP17betaCA was absent in subjects prior to FP therapy, detectable (180-1991 ng FP17betaCA/g creatinine) throughout the dosing period and reached below the LOQ at 6 days after therapy cessation.

CONCLUSIONS

Measurement of FP17betaCA by LC-MS/MS has acceptable analytical performance for clinical use. These data support the clinical utility of measuring FP17betaCA in urine to monitor patient compliance with FP therapy.

Neonatal screening for congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) caused by steroid 21-hydroxylase deficiency occurs in 1:16,000-1:20,000 births. If not promptly diagnosed and treated, CAH can cause death in early infancy from shock, hyponatremia and hyperkalemia. Affected girls usually have ambiguous genitalia but boys appear normal; therefore, newborn babies are commonly screened for CAH in the US and many other countries. By identifying babies with severe, salt-wasting CAH before they develop adrenal crises, screening reduces morbidity and mortality, particularly among affected boys. Diagnosis is based on elevated levels of 17-hydroxyprogesterone, the preferred substrate for steroid 21-hydroxylase. Initial testing usually involves dissociation-enhanced lanthanide fluorescence immunoassay that has a low positive predictive value (about 1%), which leads to many follow-up evaluations that have negative results. The positive predictive value might be improved by second-tier screening using DNA-based methods or liquid chromatography followed by tandem mass spectrometry, but these methods are not widely adopted. Cost estimates for such screening range from US$20,000 to $300,000 per life-year saved. In babies with markedly abnormal screen results, levels of serum electrolytes and 17-hydroxyprogesterone should be immediately determined, but the most reliable way to diagnose CAH is measurement of levels of steroid precursors after stimulation with cosyntropin.

Diagnosis of diseases of steroid hormone production, metabolism and action

Biochemical tests have been the basis for investigations of disorders affecting steroid hormones. In recent years it has been possible however to study the genes that determine functional enzymes, cofactors, receptors, transcription factors and signaling systems that are involved in the process. Analyses of mutations are available as a diagnostic service for only a few of these genes although research laboratories may be able to provide a service. Both biochemical and genetic research have brought to light new disorders. Some genes for transcription factors involved in the development of the endocrine organs have also been identified and patients with defects in these processes have been found. This paper will review general aspects of adrenal disorders with emphasis on clinical and laboratory findings. As with all endocrine investigations there are few single measurements that provide a definitive answer to a diagnosis. Timing of samples in relation to age, gender and time of day needs to be considered.

Steroid measurement with LC-MS/MS in pediatric endocrinology

The liquid chromatography-tandem mass spectrometry (LC-MS/MS) is an increasingly common tool in the clinical laboratory. Established applications include routine assays for detecting inborn errors of metabolism and for monitoring therapeutic drugs and steroids. Steroid profiling is a very effective method for distinguishing almost all steroid related disorders. It allows accurate diagnosis and is very useful in many clinical situations. Most methods for the determination of steroid hormones are based on immunoassays, which are rapid and easy to perform. However, the reliability of steroid immunoassays has been shown to be doubtful because of the lack of specificity and of matrix effects. Immunological methods, especially direct assays, often overestimate true steroid values. This is of particular importance in the newborn period and in early infancy. Problems with steroid immunoassays have further been reported for female patients or when analysing different media, e.g. saliva. Patient follow-up over time or between laboratories, as well as longitudinal studies are extremely difficult. In contrast to immunoassays, which allow the measurement of only a single steroid at a time, LC-MS/MS has the advantage that a wide spectrum of steroid hormones can be measured simultaneously. The applicability for clinical samples and problems in pediatric endocrinology will be discussed.

Steroid Profiles in Ovarian Follicular Fluid from Regularly Menstruating Women and Women after Ovarian Stimulation

Background: Information on the concentrations of steroids in ovarian follicular fluid (FF) from regularly menstruating (RM) women has been limited because of the absence of methods for the simultaneous quantification of multiple steroids in small volumes of FF. We studied steroid profiles in FF during the early follicular phase of the menstrual cycle and after ovarian stimulation for in vitro fertilization (IVF), and compared concentrations with published values obtained by immunoassay (IA).

Methods: We used liquid chromatography–tandem mass spectrometry (LC-MS/MS) to measure 13 steroids in 40-μL aliquots of FF samples from 21 RM women and from 5 women after ovarian stimulation for IVF. Relationships between concentrations of steroids and their ratios (representations of the enzyme activities) were evaluated within and between subgroups.

Results: The concentrations of testosterone (Te), androstenedione (A4), and estradiol (E2) measured by LC-MS/MS were lower than those previously reported in studies with IAs. In RM women, androgens were the most abundant class of steroids, with A4 being the major constituent. The concentrations of 17-hydroxyprogesterone (17OHP), total androgens, and estrogens were 200- to 1000-fold greater in FF than in serum. Compared with RM women, FF samples from women undergoing ovarian stimulation had significantly higher concentrations of E2 (P = 0.021), pregnenolone (P = 0.0022), 17OHP (P = 0.0007), and cortisol (F) (P = 0.0016), and significantly higher ratios of F to cortisone (P = 0.0006), E2 to estrone (P = 0.0008), and E2 to Te (P = 0.0013).

Conclusions: The data provide the first MS-based concentration values for 13 steroids in ovarian FF from RM women, from estrogen- and androgen-dominant follicles, and from women after ovarian stimulation for IVF.

Simultaneous quantitation of seven endogenous C-21 adrenal steroids by liquid chromatography tandem mass spectrometry in human serum

Quantitation of endogenous steroids is important in the diagnosis of several endocrine disorders. In this study we present a new method for simultaneous quantitation of cortisol, cortisone, 11-desoxycortisol, 21-desoxycortisol, corticosterone, 17-hydroxyprogesterone and 11-desoxycorticosterone in human serum by on-line extraction and LC-MS/MS. Analytes extraction was performed on-line using a 2-position and 6-port valve equipped with a monolithic silica cartridge. After chromatographic separation of all analytes, detection was performed in the multiple reaction monitoring mode using positive atmospheric pressure chemical ionization mode. Total imprecision of the assay ranged from 5.5 to 15.5%. Comparison with immunoassays yielded coefficients of 0.893 for cortisol, 0.848 for 11-desoxycortisol and 0.924 for 17-hydroxyprogesterone. The sensitivity of this method provides meaningful data for patients within normal and elevated range and it may be useful for the diagnosis of a variety of adrenal dysfunctions.

Adrenal steroid concentrations in children seven to seventeen years of age

During puberty, serum steroid concentrations change dramatically. The objective of this study was to determine the adrenal steroid concentrations in children from 7 to 17 years of age. Tanner stage was determined in each child by physical examination. 11-Deoxycortisol, pregnenolone, 17-hydroxypregnenolone, 17-hydroxyprogesterone and testosterone were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Androstenedione and dehydroepiandrosterone sulfate were measured by immunoassay. The median and central 95% of the steroid concentrations were determined for age, gender, and Tanner stage. Except for 11-deoxycortisol, all of the steroids exhibited an increase in concentration after age 7-9 years in both boys and girls. 11-Deoxycortisol, which is made exclusively in the adrenal cortex, declined with age and Tanner stage. This suggests that a rise in gonadal function and decreased efficiency of 11beta-hydroxylase with age may contribute to an increase in the remaining steroids. Testosterone concentrations increased more dramatically in boys, but increases were seen with each Tanner stage in girls.

Newborn screening for congenital adrenal hyperplasia: additional steroid profile using liquid chromatography-tandem mass spectrometry

BACKGROUND

Neonatal screening programs for congenital adrenal hyperplasia (21-CAH) using an immunoassay for 17alpha-hydroxyprogesterone (17-OHP) generate a high rate of positive results attributable to physiological reasons and to cross-reactions with steroids other than 17alpha-OHP, especially in preterm neonates and in critically ill newborns.

METHODS

To increase the specificity of the screening process, we applied a liquid chromatography-tandem mass spectrometry method quantifying 17alpha-OHP, 11-deoxycortisol, 21-deoxycortisol, cortisol, and androstenedione. The steroids were eluted in aqueous solution containing d8-17alpha-OHP and d2-cortisol and quantified in multiple reaction mode.

RESULTS

Detection limit was below 1 nmol/liter, and recovery ranged from 64% (androstenedione) to 83% (cortisol). Linearity was proven within a range of 5-100 nmol/liter (cortisol, 12.5-200 nmol/liter), and total run time was 6 min. Retrospective analysis of 6151 blood samples and 50 blood samples from newborns with clinically confirmed 21-CAH, as well as prospective analysis of 1609 samples of a total of 242,500 testing positive in our routine 17-OHP immunoassay, allowed clear distinction of affected and nonaffected newborns. High levels of 21-deoxycortisol were only found in children with 21-hydroxylase deficiency. Calculating the ratio of 17alpha-OHP to 21-deoxycortisol divided by cortisol further increased the sensitivity of the method.

CONCLUSION

Our liquid chromatography-tandem mass spectrometry procedure as a second-tier test can be used to reduce false-positive results of standard 21-CAH screening. The short total run time of 6 min allows for immediate reanalysis of all immunoassay results above the cutoff.