Salivary cortisone is a potential biomarker for serum free cortisol

The Effects of Single-Dose Etomidate Versus Propofol on Cortisol Levels in Pediatric Patients Undergoing Urologic Surgery: A Randomized Controlled Trial

BACKGROUND

The effects of general anesthetics on the hypothalamus-pituitary-adrenal axis and cortisol release in children are poorly characterized. Normal, daily fluctuation of cortisol levels complicates assessment of these effects. This study aimed to characterize the effects of etomidate compared with propofol on the normal cortisol secretory pattern in children undergoing urologic surgery by using a salivary cortisol assay.

METHODS

In this prospective, randomized, double-blind, controlled study, we recruited 80 children aged 3 to 12 years assigned ASA physical status I who were scheduled for urologic surgery and 11 healthy child volunteers. Before surgery, cortisol levels of the 11 volunteers and 15 study patients were tested from 7:00 AM to 9:00 PM every hour for 1 day. The study patients were then randomly allocated into an etomidate group and a propofol group, receiving etomidate 0.3 mg/kg (n = 38) or propofol 2 mg/kg (n = 39) and midazolam 0.1 mg/kg, fentanyl 2 μg/kg, and rocuronium 0.6 mg/kg for induction, respectively. The cortisol levels of the patients were assessed continuously for 2 days postoperatively.

RESULTS

The cortisol levels of the etomidate group were continuously and significantly lower than those of the propofol group from the time of discharge from the postanesthesia care unit (approximately 2:00 PM) until 8:00 AM the next morning (all P < 0.0001) and were significantly lower than before surgery at the same time points (all P < 0.0001). Except at 11:00 AM just before the operation, no significant differences in cortisol levels were detected before and after the operation in the propofol group (P max = 0.476, P min = 0.002). Also, no significant differences in clinical outcomes were detected between the 2 groups undergoing surgery (all P > 0.070).

CONCLUSIONS

Compared with propofol, a single induction dose of etomidate suppressed postoperative cortisol levels in healthy children undergoing urologic surgery. This suppression lasted approximately 24 hours and was not associated with any changes in clinical outcomes.

Assessment of the cortisol awakening response: Expert consensus guidelines

The cortisol awakening response (CAR), the marked increase in cortisol secretion over the first 30-45 min after morning awakening, has been related to a wide range of psychosocial, physical and mental health parameters, making it a key variable for psychoneuroendocrinological research. The CAR is typically assessed from self-collection of saliva samples within the domestic setting. While this confers ecological validity, it lacks direct researcher oversight which can be problematic as the validity of CAR measurement critically relies on participants closely following a timed sampling schedule, beginning with the moment of awakening. Researchers assessing the CAR thus need to take important steps to maximize and monitor saliva sampling accuracy as well as consider a range of other relevant methodological factors. To promote best practice of future research in this field, the International Society of Psychoneuroendocrinology initiated an expert panel charged with (i) summarizing relevant evidence and collective experience on methodological factors affecting CAR assessment and (ii) formulating clear consensus guidelines for future research. The present report summarizes the results of this undertaking. Consensus guidelines are presented on central aspects of CAR assessment, including objective control of sampling accuracy/adherence, participant instructions, covariate accounting, sampling protocols, quantification strategies as well as reporting and interpreting of CAR data. Meeting these methodological standards in future research will create more powerful research designs, thus yielding more reliable and reproducible results and helping to further advance understanding in this evolving field of research.

The hyporeactivity of salivary cortisol at stress test (TSST-C) in children with internalizing or externalizing disorders is contrastively associated with α-amylase

BACKGROUND

Stress biomarkers of the autonomic nervous system and hypothalamic-pituitary-adrenal axis (HPA-axis) can be measured via alpha-amylase (AA) and cortisol and cortisone in saliva. Objectives were to determine 1) the response patterns of cortisol, cortisone, and AA under both circadian conditions and the Trier Social Stress Test for Children (TSST-C), 2) which reactivity index is most suitable to differentiate internalizing or externalizing disorders from controls, and to explore 3) the interaction between AA and cortisol in the presence of internalizing or externalizing disorders.

METHODS

Saliva samples (n = 2893) from children with internalizing (n = 55) or externalizing disorders (n = 33) and healthy children (n = 81) were analyzed for cortisol, cortisone, and AA under circadian conditions and TSST-C.

RESULTS

Circadian rhythm of three biomarkers did not differ between diagnostic groups. Age and gender were significant predictors for cortisol and awakening time influenced all three biomarkers significantly. TSST-C responses appeared sequentially in the order of AA, cortisol, and cortisone. Trajectories of cortisol and cortisone responses, not in AA, were significantly lower in children with internalizing or externalizing disorders than in healthy children. Cortisol percentage increase appeared to be the most suitable reactivity index to detect the difference between the diagnostic groups. Internalizing disorders had a negative association between AA decrease and cortisol increase (β = -.199, p < .05, R(2) = .304). Externalizing disorders had a positive association between AA baseline and cortisol increase (β = .229, p < .05, R(2) = .304).

CONCLUSION

An altered HPA-axis response during stress might result from chronic allostatic load in internalizing disorders and underaroused stress response system in externalizing disorders.

Determinants of hair cortisol and hair cortisone concentrations in adults

BACKGROUND

The analysis of hair cortisol concentrations (HairF) is a promising new tool for the assessment of long-term cortisol. With the development of multiple steroid analyses by means of liquid chromatography tandem-mass spectrometry (LC-MS/MS), the analysis of cortisone in hair (HairE) has also been facilitated. However, the influence of various types of determinants on HairF and HairE is still largely unknown. This study systematically assesses the influence of sociodemographic, health, lifestyle, and hair (treatment) characteristics on HairF and HairE.

METHOD

Data of 760 psychiatrically healthy participants (71.8% female, mean age 45.89 years) of the Netherlands Study of Depression and Anxiety (NESDA) were used. HairF and HairE were measured in the proximal 3 cm of scalp hair, using LC-MS/MS.

FINDINGS

HairF and HairE strongly correlated. In simple linear regressions, HairF and HairE were higher in older age, in presence of diabetes mellitus, and in men compared to women. More frequent washing of the hair was associated with lower HairF and HairE. Darker hair colours were associated with higher HairF and HairE. An effect of season and of use of oral contraceptives was found for HairF. After full mutual adjustment, only age, presence of diabetes mellitus, hair washing frequency, and season remained significant determinants of HairF.

INTERPRETATION

This large-scale study shows that HairF and HairE are upregulated in older age and in the presence of diabetes mellitus. This suggests that these levels are important for somatic health and should be taken into account when using hair corticosteroid analysis in future studies.

PERFORMANCE OF FREE VERSUS TOTAL CORTISOL FOLLOWING COSYNTROPIN STIMULATION TESTING IN AN OUTPATIENT SETTING

OBJECTIVE

Free cortisol (FC) is potentially superior to total cortisol (TC) measurements in selected clinical settings; however, the advantages of uniform use of FC in outpatient settings are unclear. The objectives of this study were to describe the dynamic response of FC during cosyntropin stimulation testing (CST) compared to TC and to determine the rates of discordance.

METHODS

This is a cross-sectional study of 295 stable patients who underwent CST in an outpatient Endocrine Testing Center. The main outcome measures were TC and FC measurements during CST.

RESULTS

The mean age of the 295 subjects was 49.1 (16.9) years. Of 218 females, 43 were taking estrogen therapy (ET) at the time of testing. Adrenal insufficiency (AI) was diagnosed in 41/295 (14%) patients. The FC concentrations were associated with TC concentrations at baseline (R(2) = 0.77, P<.001), 30 minutes (R(2) = 0.87, P<.001), and 60 minutes (R(2) = 0.90, P<.001). The FC cutoffs for AI were 873 and 1,170 ng/dL at 30 and 60 minutes, respectively. The FC had a more pronounced fold change from baseline to peak than TC (median 3.2 vs. 1.7, P<.001). Both TC and FC at baseline were higher in females on ET compared to those who were not and to males; however, peak TC and FC values were similar. In 3/43 females on ET, FC, and TC results were discordant (P = .003).

CONCLUSION

We report 99% concordance of TC and FC measurements in a large outpatient cohort. The discordant rates were high in females treated with ET (7%). The FC measurements during CST in females on ET may provide a more rapid and accurate diagnosis of AI.

Mass spectrometry and immunoassay: how to measure steroid hormones today and tomorrow

The recent onslaught of mass spectrometry (MS) to measurements of steroid hormones, including demands that they should be the only acceptable method, has confused clinicians and scientists who have relied for more than 40 years on a variety of immunoassay (IA) methods in steroid hormone measurements. There is little doubt that MS methods with their superior specificity will be the future method of choice in many clinical and research applications of steroid hormone measurement. However, the majority of steroid measurements are currently, and will continue to be, carried out using various types of IAs for several reasons, including their technical ease, cost and availability of commercial reagents. Speedy replacement of all IAs with MS is an unrealistic and unnecessary goal, because the availability of MS measurements is limited by cost, need of expensive equipment, technical demands and lack of commercial applications. Furthermore, IAs have multiple well-known advantages that vindicate their continuing use. The purpose of this article is to elucidate the advantages and limitations of the MS and IA techniques from two angles, i.e. promotion of MS and defence of IA. The purpose of the text is to give the reader an unbiased view about the current state and future trends of steroid analysis and to help him/her choose the correct assay method to serve his/her diagnostic and research needs.

Stress During Pregnancy

High levels of stress during pregnancy are associated with a number of adverse psychological and physiological outcomes for mother and child. These effects seem to be transmitted in part by one of the major stress-responsive systems, namely the hypothalamic-pituitary-adrenal (HPA) axis, which includes the hormone cortisol. However, as inconsistent study results indicate, methodology poses a substantial challenge to the investigation of stress during pregnancy. For example, although measures of maternal psychological stress and stress hormones are independently related to adverse pregnancy outcome, they seldom have been found to correlate with one another directly. Repeated measurement of psychological and biological responses to acute standardized stress challenges appears to reveal stronger associations. This article reviews the literature on experienced stress and stress hormones in pregnant women and presents studies that used standardized stress challenges (e.g., the Trier Social Stress Test, the cortisol response to morning awakening) to examine maternal stress reactivity more systematically. This review also takes a look at the few studies that examined the protective effects of psychological and psychosocial resources or stress interventions on experienced stress and stress hormones in pregnant women. Overall, results indicate that baseline stress hormone levels advance incrementally during gestation, presumably to prepare mother and fetus for delivery, while responses to acute stress appear to be increasingly attenuated. Moreover, the acute maternal stress response seems to be predictive of neonatal birth outcome and maternal well-being postpartum. Preliminary findings also suggest that much can be done toward coping with stress during pregnancy. Further research and a closer collaboration between science and clinical practice are required.

Subclinical hypercortisolism in adrenal incidentaloma

PURPOSE OF REVIEW

The article aims to update the reader on current developments in the area of adrenal incidentaloma complicated by subclinical hypercortisolism. We will discuss different diagnostic strategies and complications associated with this disease, and address the conflicting opinions related to the treatment of these patients.

RECENT FINDINGS

Depending on diagnostic criteria used, between 30 and 50% of patients with adrenocortical incidentaloma have biochemical hypercortisolism, but lack classical external features of Cushing's syndrome. The challenge facing the clinician is that in the sixth and seventh decade of life hypertension, diabetes, osteoporosis and obesity are common and establishing whether these are directly related to the low-grade excess cortisol secretion in a given individual is not straightforward. Nevertheless, this subclinical hypercortisolism has been found to be associated with multiple cardiovascular risk factors, an increased predisposition to cardiovascular events and a higher mortality rate. The dilemma is that it is not established whether surgical excision of the adrenal adenoma in a given individual will improve these complications, and data demonstrate that surgical studies are conflicting.

SUMMARY

Subclinical hypercortisolism is associated with multiple complications and definite guidelines for diagnosis are necessary. Prospective, randomized controlled studies are needed to ascertain whether medical or surgical interventions are justified, and in which patients.

Cushing syndrome: update on testing

Endogenous hypercortisolism (Cushing syndrome) is one of the most enigmatic diseases in clinical medicine. The diagnosis and differential diagnosis of Cushing syndrome depend on proper laboratory evaluation. In this review, an update is provided on selected critical issues in the diagnosis and differential diagnosis of Cushing syndrome: the use of late-night salivary cortisol in initial diagnosis and for postoperative surveillance, and the use of prolactin measurement to improve the performance of inferior petrosal sinus sampling to distinguish Cushing disease from ectopic adrenocorticotropic hormone (ACTH) syndrome during differential diagnosis of ACTH-dependent Cushing syndrome.

Salivary cortisol and cortisone responses to tetracosactrin (synacthen)

Background

To establish cutoff values for salivary liquid chromatography tandem mass spectroscopy cortisol and cortisone in defining adequate adrenocortical function during a standard synacthen test.

Methods

We compared salivary liquid chromatography tandem mass spectroscopy cortisol and cortisone responses to those of serum cortisol measured on the Roche E170 immunoassay analyser and the Abbott Architect i2000 before and 30 min and 60 min following 0.25 mg of intravenous synacthen.

Results

Correlations of salivary cortisol and cortisone were bimodal and linear, respectively. Based on these correlations, adequate salivary cortisol and cortisone responses to synacthen were extrapolated from a serum cortisol (Roche) cut-off of 550 nmol/L and defined as 15 nmol/L and 45 nmol/L, respectively. The Abbott method correlated well with the Roche but gave results that were about 20% lower than the Roche method.

Conclusions

Measurement of salivary cortisol and cortisone responses offers an alternative to those of serum cortisol during a synacthen test in the investigation of adrenal hypofunction.

Optimal glucocorticoid replacement in adrenal insufficiency

Adrenal insufficiency (glucocorticoid deficiency) comprises a group of rare diseases, including primary adrenal insufficiency, secondary adrenal insufficiency and congenital adrenal hyperplasia. Lifesaving glucocorticoid therapy was introduced over 60 years ago, but since then a number of advances in treatment have taken place. Specifically, little is known about short- and long-term treatment effects, and morbidity and mortality. Over the past decade, systematic cohort and registry studies have described reduced health-related quality of life, an unfavourable metabolic profile and increased mortality in patients with adrenal insufficiency, which may relate to unphysiological glucocorticoid replacement. This has led to the development of new modes of replacement that aim to mimic normal glucocorticoid physiology. Here, evidence for the inadequacy of conventional glucocorticoid therapy and recent developments in treatment are reviewed, with an emphasis on primary adrenal insufficiency.

Hair cortisol and cortisol awakening response are associated with criteria of the metabolic syndrome in opposite directions

Findings on the association between hypothalamic-pituitary-adrenal (HPA) axis activity and metabolic risk are equivocal. Different methods of measuring HPA activity might indicate adverse vs. beneficial effects of HPA activity on metabolic risk thus contributing to heterogenous findings. In this study, we aimed to determine whether (1) the salivary cortisol awakening response (CAR) as a marker of awakening-induced activation of the HPA axis and (2) hair cortisol as a marker of long-term cortisol secretion are associated with criteria of the metabolic syndrome. Therefore, we recruited 41 healthy individuals (26 women, mean age: 41.2 years) and 44 patients with major depression (28 women, 41.4 years) and assessed CAR and hair cortisol values as well as all criteria of the metabolic syndrome (abdominal obesity, blood pressure, plasma glucose, triglycerides and high-density cholesterol levels) according to the International Diabetes Federation. CAR and hair cortisol values were divided into tertiles. Across groups, participants with hair cortisol or hair cortisone in the highest tertile showed significantly more criteria of the metabolic syndrome compared to participants in the medium or low tertile (F2,64=3.37, p=.04). These results were corroborated by significant positive correlations between mean hair cortisol values with waist circumference (r=.29, p=.03), triglycerides (r=.34, p=.01) and systolic blood pressure (r=.29, p=.04) and between mean hair cortisone and triglycerides (r=.46, p<.01). In contrast, mean CAR values correlated negatively with diastolic (r=-.29, p=.03) and systolic blood pressure (r=-.32, p=.02). Our results indicate that higher hair cortisol and hair cortisone levels but lower CAR values are associated with an unfavorable metabolic and cardiovascular risk profile.

Network-based approach for analyzing intra- and interfluid metabolite associations in human blood, urine, and saliva

Most studies investigating human metabolomics measurements are limited to a single biofluid, most often blood or urine. An organism's biochemical pool, however, comprises complex transboundary relationships, which can only be understood by investigating metabolic interactions and physiological processes spanning multiple parts of the human body. Therefore, we here propose a data-driven network-based approach to generate an integrated picture of metabolomics associations over multiple fluids. We performed an analysis of 2251 metabolites measured in plasma, urine, and saliva, from 374 participants of the Qatar Metabolomics Study on Diabetes (QMDiab). Gaussian graphical models (GGMs) were used to estimate metabolite-metabolite interactions on different subsets of the data set. First, we compared similarities and differences of the metabolome and the association networks between the three fluids. Second, we investigated the cross-talk between the fluids by analyzing correlations occurring between them. Third, we propose a framework for the analysis of medically relevant phenotypes by integrating type 2 diabetes, sex, age, and body mass index into our networks. In conclusion, we present a generic, data-driven network-based approach for structuring and visualizing metabolite correlations within and between multiple body fluids, enabling unbiased interpretation of metabolomics multifluid data.

Physiological basis for the etiology, diagnosis, and treatment of adrenal disorders: Cushing's syndrome, adrenal insufficiency, and congenital adrenal hyperplasia

The hypothalamic-pituitary-adrenal (HPA) axis is a classic neuroendocrine system. One of the best ways to understand the HPA axis is to appreciate its dynamics in the variety of diseases and syndromes that affect it. Excess glucocorticoid activity can be due to endogenous cortisol overproduction (spontaneous Cushing's syndrome) or exogenous glucocorticoid therapy (iatrogenic Cushing's syndrome). Endogenous Cushing's syndrome can be subdivided into ACTH-dependent and ACTH-independent, the latter of which is usually due to autonomous adrenal overproduction. The former can be due to a pituitary corticotroph tumor (usually benign) or ectopic ACTH production from tumors outside the pituitary; both of these tumor types overexpress the proopiomelanocortin gene. The converse of Cushing's syndrome is the lack of normal cortisol secretion and is usually due to adrenal destruction (primary adrenal insufficiency) or hypopituitarism (secondary adrenal insufficiency). Secondary adrenal insufficiency can also result from a rapid discontinuation of long-term, pharmacological glucocorticoid therapy because of HPA axis suppression and adrenal atrophy. Finally, mutations in the steroidogenic enzymes of the adrenal cortex can lead to congenital adrenal hyperplasia and an increase in precursor steroids, particularly androgens. When present in utero, this can lead to masculinization of a female fetus. An understanding of the dynamics of the HPA axis is necessary to master the diagnosis and differential diagnosis of pituitary-adrenal diseases. Furthermore, understanding the pathophysiology of the HPA axis gives great insight into its normal control.

Do venepuncture procedures induce cortisol responses? A review, study, and synthesis for stress research

Venepuncture procedures are frequently employed to continuously monitor humoral stress markers. As such procedures are conceived as "potent psychological and physiological stressors", there is a need to determine whether venepuncture procedures themselves elicit cortisol responses and if so, how to deal with them appropriately. In order to assess the rate of cortisol responses to venepuncture, we conducted a literature review, which suggested that venepuncture procedures induce cortisol responses with a probability of approximately 30%. By utilizing Bayesian analysis, this result was integrated with the cortisol data of 18 healthy men who were exposed to a venepuncture procedure twice (time lag: 1 week). The currently observed response rate of 47% differed substantially from the earlier findings, which we attribute to a self-selective sampling of participants. In addition, participants showing a response to the first venepuncture were highly likely to also show a response to the second one. In this regard, we discuss the presumed conditioning of cortisol responses to venepuncture procedures. To prevent the superposition of venepuncture-induced cortisol responses and responses induced by target stressors, we propose a time- and selection-based strategy: cortisol samples taken about 110min after venepuncture should be virtually adjusted for its superimposing effects. Furthermore, previous experiences of venepuncture were highly predictive for cortisol responsiveness. This association could be utilized in further studies to identify participants who will probably show a cortisol response to venepuncture.

Continuous subcutaneous hydrocortisone infusion versus oral hydrocortisone replacement for treatment of addison's disease: a randomized clinical trial

CONTEXT

Conventional glucocorticoid replacement therapy fails to mimic the physiological cortisol rhythm, which may have implications for morbidity and mortality in patients with Addison's disease.

OBJECTIVE

The objective of the study was to compare the effects of continuous sc hydrocortisone infusion (CSHI) with conventional oral hydrocortisone (OHC) replacement therapy.

DESIGN, PATIENTS, AND INTERVENTIONS

This was a prospective crossover, randomized, multicenter clinical trial comparing 3 months of treatment with thrice-daily OHC vs CSHI. From Norway and Sweden, 33 patients were enrolled from registries and clinics. All patients were assessed at baseline and after 8 and 12 weeks in each treatment arm.

MAIN OUTCOME MEASURES

The morning ACTH level was the primary outcome measure. Secondary outcome measures were effects on metabolism, health-related quality of life (HRQoL), sleep, and safety.

RESULTS

CSHI yielded normalization of morning ACTH and cortisol levels, and 24-hour salivary cortisol curves resembled the normal circadian variation. Urinary concentrations of glucocorticoid metabolites displayed a normal pattern with CSHI but were clearly altered with OHC. Several HRQoL indices in the vitality domain improved over time with CSHI. No benefit was found for either treatments for any subjective (Pittsburgh Sleep Quality Index questionnaire) or objective (actigraphy) sleep parameters.

CONCLUSION

CSHI safely brought ACTH and cortisol toward normal circadian levels without adversely affecting glucocorticoid metabolism in the way that OHC did. Positive effects on HRQoL were noted with CSHI, indicating that physiological glucocorticoid replacement therapy may be beneficial and that CSHI might become a treatment option for patients poorly controlled on conventional therapy.

Comparison of total cortisol, free cortisol, and surrogate markers of free cortisol in diagnosis of adrenal insufficiency in patients with stable cirrhosis

BACKGROUND & AIMS

Measurements of serum levels of total cortisol can overestimate the prevalence of adrenal dysfunction in patients with cirrhosis because they have low concentrations of corticosteroid-binding globulin and albumin. We used measurements of serum total cortisol and serum free cortisol after the low-dose short Synacthen test (LDSST) to assess adrenal dysfunction.

METHODS

We studied 79 patients with stable cirrhosis; adrenal dysfunction was defined by peak concentrations of total cortisol ≤494 mmol/L and/or peak concentrations of free cortisol ≤33 nmol/L after the LDSST. We determined free cortisol index (FCI) scores and calculated free cortisol levels by using Coolens' equation. The Cox regression model was used to assess the relationship between adrenal dysfunction and outcomes (death or liver transplant).

RESULTS

On the basis of measurement of total cortisol, 34% of patients had adrenal dysfunction, and on the basis of measurement of free cortisol, 29% had adrenal dysfunction. There was agreement between total cortisol and free cortisol levels in 22% of patients; in 13%, adrenal dysfunction was diagnosed only on the basis of total cortisol and in 6% only on the basis of free cortisol (κ coefficient, 0.56; P < .01). Low concentrations of corticosteroid-binding globulin (21 vs 54 μg/mL, P < .01) led to an overestimation of adrenal dysfunction that was based on measurement of total cortisol. Measurements of calculated free cortisol constantly overestimated free cortisol concentrations, with variations as large as 87% for baseline values and up to 84% after stimulation. Adrenal insufficiency, defined by FCI scores <12, was detected in 30% of patients; among them, 23% also had subnormal peak levels of free cortisol (κ coefficient, 0.70; P < .001). Adrenal dysfunction was not significantly associated with patient outcomes, on the basis of Cox model analysis.

CONCLUSIONS

Adrenal insufficiency, defined by LDSST, is frequent in patients with stable cirrhosis, on the basis of measurements of total and free cortisol. FCI scores are better than measurement of total cortisol in assessing adrenal function in patients with cirrhosis. We did not associate adrenal dysfunction with outcome, but further studies are needed.

Early morning salivary cortisol and cortisone, and adrenal responses to a simplified low-dose short Synacthen test in children with asthma

OBJECTIVE

To examine serum cortisol responses to a simplified low-dose short Synacthen test (LDSST) in children treated with inhaled corticosteroids (ICS) for asthma and to compare these to early morning salivary cortisol (EMSC) and cortisone (EMSCn) levels.

DESIGN

Early morning salivary cortisol and EMSCn samples were collected for three consecutive days. On day three, Synacthen 500 ng/1·73 m(2) was administered intravenously. Samples were collected at 0, 15, 25, 35 min.

RESULTS

A total of 269 subjects (160 M: 109 F), median (range) age 10·0 (5·1-15·2) years were studied. Peak cortisol in the LDSST was <500 nmol/l in 101 subjects (37·5%) and <350 nmol/l in 12 subjects (4·5%). Basal cortisol correlated with peak cortisol: r = 0·55, (95% CI: 0·46, 0·63, P < 0·0001). Time at which peak cortisol concentration was achieved was significantly related to the value of peak cortisol (P < 0·0001), with higher cortisol peaks occurring later in the test and lower cortisol peaks occurring earlier. EMSC and EMSCn had no predictive value for the identification of patients with a peak cortisol <500 nmol/l. EMSCn was superior to EMSC in identifying patients with a peak cortisol <350 nmol/l: a minimum EMSCn cut-off value of 12·5 nmol/l gave a negative predictive value of 99·2% and positive predictive value of 30·1%.

CONCLUSION

Our data illustrate that basal measures of cortisol are likely to be of value in screening populations for patients at greatest risk of adrenal crisis. EMSCn shows promise as a screening tool for the identification of patients with severe adrenal insufficiency.

Serum cortisol seems to be a more appropriate marker for adrenocortical reserve evaluation in ACTH test in comparison to salivary cortisol

Salivary cortisol reflects the free fraction of serum cortisol. Monitoring salivary cortisol may be a promising alternative method for assessing serum cortisol in some clinical situations. We aimed to compare the reliability of salivary vs. serum cortisol during ACTH test. 84 subjects (mean age 63.2; 24-89 years; n=66 males) suspected for adrenocortical insufficiency underwent an ACTH test. Patients were divided based on peak serum cortisol into hypocortical group with cortisol <500 nmol/l and to reference group cortisol >500 nmol/l. Median serum cortisol levels in reference group were 445, 766, and 902 nmol/l at 0, 30, and 60 minutes, respectively, and in hypocortical group were 256, 394, and 453 nmol/l. Median salivary cortisol levels were 19.02, 40.02, and 62.1 nmol/l in reference group, and 9.60, 14.08, and 13.28 nmol/l in hypocortical group. Obtained values showed good correlation between serum and salivary cortisol (p<0.0001). The percentage of explained variability R(2) (coefficient of determination for linear model) representing a measure of agreement between experimental values and predictions for repeated measures ANOVA, was significantly higher (p=0.021) for serum cortisol (R2=93.4 %) when compared to the salivary cortisol (R2=89.3 %). A stronger discriminating power of serum versus salivary cortisol suggests that it seems to be slightly, but statistically significantly more appropriate marker of adrenocortical reserve in ACTH test.

Novel liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for measuring steroids

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is increasingly becoming the method of choice for steroid hormone measurements due to small sample volumes, fast analysis times and improved specificity compared to immunoassays. Achievement of demanding analytical targets for steroid analysis is now becoming possible because of improvements in sample preparation technology, liquid chromatography column technology and mass spectrometer design. The most popular sample treatment strategies comprise protein precipitation (PP), solid-phase extraction (SLE) and liquid-liquid extraction (LLE). Modern liquid chromatography columns can ensure the adequate separation of isobaric compounds e.g. 21 Deoxycortisol, 11 Deoxycortisol and Corticosterone. The most appropriate method may be chosen to improve assay sensitivity by reducing matrix effects (LLE, SPE) or simplicity and speed (PP). Specific examples of some clinically important steroids including oestradiol, aldosterone, renin, serum cortisol, salivary cortisol and salivary testosterone will be described.

Update on late-night salivary cortisol for the diagnosis of Cushing's syndrome: methodological considerations

Late-night salivary cortisol (LNSC) is now considered the best approach to screen patients suspected of having endogenous hypercortisolism (Cushing's syndrome). As the use of LNSC increases, new preanalytic and analytic issues have arisen. The routine immunoassay for salivary cortisol seems to have better diagnostic performance than liquid chromatograph/tandem mass spectrometry, although measurement of normal salivary cortisone concentrations with the latter technique is very useful in identifying samples contaminated with topical hydrocortisone. LNSC is very useful in screening for Cushing's syndrome in women with increased corticosteroid-binding globulin resulting from estrogen therapy or pregnancy. Two LNSCs from each patient is recommended for routine screening, although one adequate saliva sample seems to perform well. The overnight dexamethasone suppression test remains superior to LNSC in the evaluation of potential subclinical hypercortisolism in patients with adrenal incidentalomas. Periodic assessment of LNSC is extremely useful in monitoring patients for recurrence of Cushing's disease after pituitary surgery. With the large increase in the number LNSCs being ordered around the world, it is likely that more preanalytic and analytic issues will arise, which laboratorians and clinical chemists will need to resolve.

The association between perceived emotional support, maternal mood, salivary cortisol, salivary cortisone, and the ratio between the two compounds in response to acute stress in second trimester pregnant women

OBJECTIVE

Little is known about the effect of social support on the reactivity of the hypothalamic-pituitary-adrenal (HPA) axis during pregnancy. Moreover, when investigating the HPA axis most studies do not consider the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), an enzyme within the salivary glands that inactivates cortisol to cortisone. This study explores the association between perceived emotional support and the maternal psychobiological stress response to a standardized naturalistic stressor by assessing maternal mood and the reactivity of salivary cortisol (SalF), salivary cortisone (SalE), and the SalE/(E+F) ratio as a marker of 11β-HSD2 activity.

METHODS

Repeated saliva samples and measures of maternal mood were obtained from 34 healthy second trimester pregnant women undergoing amniocentesis which served as a psychological stressor. The pregnant women additionally responded to a questionnaire of perceived emotional support and provided sociodemographic (e.g., maternal educational degree) and pregnancy-specific data (e.g., planned versus unplanned pregnancy).

RESULTS

Perceived emotional support neither showed a significant effect on mood nor on the SalF or SalE response to stress. However, a moderately strong positive association was found between perceived emotional support and SalE/(E+F) (r=.49). Additionally, the final regression analysis revealed a significant negative relationship between educational degree, planned/unplanned pregnancy and SalE/(E+F).

CONCLUSION

Findings suggest a higher metabolization of cortisol to cortisone in pregnant women with higher emotional support. In contrast, higher maternal education and unplanned pregnancy appear to be associated with decreased salivary 11β-HSD2 activity. The current study emphasizes the importance of taking the activity of 11β-HSD2 into account when examining SalF.

The association between the acute psychobiological stress response in second trimester pregnant women, amniotic fluid glucocorticoids, and neonatal birth outcome

The underlying biological mechanism of prenatal stress in humans is poorly understood, but maternal cortisol (F) excess seems to play an important role. In pregnant rats, acute stress causes an up-regulation of placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), an enzyme present throughout the body (e.g., placenta, salivary glands) that inactivates F to cortisone (E), thereby protecting the fetus from maternal F overexposure. Whether acute stress influences human 11β-HSD2 is unclear. We aimed to explore the association between the maternal stress reactivity and amniotic fluid F, E, and the E/(E + F) ratio as a marker of fetoplacental 11β-HSD2. The predictive value of all markers for birth outcome was investigated. We examined 34 healthy pregnant women undergoing amniocentesis, which served as a standardized, real-life stressor. F, E, and E/(E + F) were determined from a single aliquot of amniotic fluid, and from saliva samples collected repeatedly. Subjects filled out state questionnaires repeatedly and were re-examined in a control condition after notification of a normal amniocentesis result. During amniocentesis, psychological stress, salivary F (SalF), and salivary E (SalE) increased significantly, whereas SalE/(E + F) decreased. The SalF reactivity was positively associated with amniotic E, while SalE/(E + F) was inversely associated with amniotic E/(E + F). SalF and SalE predicted lower and SalE/(E + F) higher birth weight. Psychological and amniotic fluid variables were unrelated to birth outcome. Findings indicate that maternal F is inactivated to E in the human fetoplacental unit during acute stress. Increased 11β-HSD2 activity within the maternal salivary glands following acute stress may mirror further stress protective mechanisms worthwhile investigating.

Therapy of adrenal insufficiency: an update

Adrenal insufficiency may be caused by the destruction or altered function of the adrenal gland with a primary deficit in cortisol secretion (primary adrenal insufficiency) or by hypothalamic-pituitary pathologies determining a deficit of ACTH (secondary adrenal insufficiency). The clinical picture is determined by the glucocorticoid deficit, which may in some conditions be accompanied by a deficit of mineralcorticoids and adrenal androgens. The substitutive treatment is aimed at reducing the signs and symptoms of the disease as well as at preventing the development of an addisonian crisis, a clinical emergency characterized by hypovolemic shock. The oral substitutive treatment should attempt at mimicking the normal circadian profile of cortisol secretion, by using the lower possible doses able to guarantee an adequate quality of life to patients. The currently available hydrocortisone or cortisone acetate preparations do not allow an accurate reproduction of the physiological secretion pattern of cortisol. A novel dual-release formulation of hydrocortisone, recently approved by EMEA, represents an advancement in the optimization of the clinical management of patients with adrenal insufficiency. Future clinical trials of immunomodulation or immunoprevention will test the possibility to delay (or prevent) the autoimmune destruction of the adrenal gland in autoimmune Addison's disease.

Cortisol in hair and the metabolic syndrome

CONTEXT

Although exposure to supraphysiological levels of glucocorticoids is known to contribute to the development of the metabolic syndrome (MetS), the importance of physiological variation in basal cortisol secretion is less clear. This issue can be addressed by using hair cortisol analysis, which for the first time allows the assessment of long-term integrated hormone levels.

OBJECTIVE AND DESIGN

We used the analysis of cortisol in hair (hairF) to examine associations of long-term cortisol levels with prevalence of MetS and individual cardiometabolic parameters in a large occupational cohort. In additional exploratory analyses, we also studied cardiometabolic associations with hair cortisone levels.

PARTICIPANTS

Participants included 1258 employees of a large aerospace company (aged 16-64 years; 84.8% males) who partook in a voluntary health assessment.

MAIN OUTCOME MEASURES

The first 3 cm of scalp-near hair were analyzed for glucocorticoid concentrations using liquid chromatography tandem mass spectrometry. Relevant cardiometabolic risk factors were assessed and MetS was diagnosed (according to 2009 international task force criteria).

RESULTS

A higher prevalence of MetS was seen in individuals falling into the third (odds ratio 1.71, 95% confidence interval 1.08-2.69) or fourth hairF quartile (odds ratio 2.42, 95% confidence interval 1.55-3.75) compared with the first quartile, in fully adjusted analyses. HairF also showed positive associations with weight-related anthropometric measures (body mass index, waist to hip ratio, waist circumference) and glycated hemoglobin. The exploratory analysis of hair cortisone also indicated relevant associations with cardiometabolic parameters.

CONCLUSION

Normal physiological differences in long-term cortisol secretion, as assessed in hair, show relevant relationships with MetS and individual cardiometabolic parameters.

The use of mass spectrometry to improve the diagnosis and the management of the HPA axis

Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) is becoming a standard analytical tool in the clinical laboratory for the measurement of small molecules, including steroid hormones. Endocrinologists are coming to acknowledge the superior quality of measurement that is achievable by LC-MS/MS through the enhanced analytical specificity and high sensitivity that this technique offers over conventional immunoassay (IA) methodologies. Additionally, LC-MS/MS overcomes many of the problems encountered in immunoassays, such as anti-reagent antibody interferences and cross-reactivity with structurally related compounds. The potential benefits of applying LC-MS/MS for the assessment of the hypothalamic-pituitary-adrenal (HPA) axis are beginning to be realised. This review critically evaluates recent developments in the application of LC-MS/MS for measurement of glucocorticoids and mineralocorticoids towards the diagnosis and management of HPA axis disorders and aims to address the current unmet need in this expanding field of endocrinology for which future studies into the potential applications of LC-MS/MS should be directed.

What is the best diagnostic and therapeutic management strategy for an Addison patient during pregnancy?

A new diagnosis of primary adrenal insufficiency (PAI) during pregnancy is extremely rare and difficult to recognize as signs and symptoms such as nausea, fatigue and hypotension may resemble features of normal pregnancy. However, if the diagnosis is overlooked and steroid replacement delayed, subsequent adrenal crisis triggered by hyperemesis gravidarum, fever or delivery can cause severe maternal and foetal morbidity and even mortality. In case of clinical suspicion of PAI, we recommend to measure paired samples of cortisol and ACTH and, if clinically feasible, a short synacthen test. We propose trimester-specific pass cut-offs for the short synacthen test that take into account the rise of total and also free cortisol during pregnancy. Empirical hydrocortisone treatment should never be delayed if the clinical suspicion is high. All pregnant women with PAI should be monitored by a team of endocrine and obstetric specialists. The third trimester is physiologically associated with a rise not only in total but also free cortisol and thus requires regular adjustment of the glucocorticoid dose. Mineralocorticoid requirements may change during pregnancy due to the anti-mineralocorticoid properties of progesterone. As plasma renin physiologically increases in pregnancy, monitoring is limited to clinical assessment including blood pressure and serum electrolytes. It is crucial that a pregnant woman with PAI and her partner are well educated regarding the adjustment of glucocorticoid dose in intercurrent illness and that both are trained in hydrocortisone emergency injection techniques. The obstetric staff should be provided with clear and written guidance for hydrocortisone cover during labour and delivery. With the appropriate replacement therapy, PAI patients can expect to have an uneventful pregnancy and deliver a healthy infant.

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.

Circadian rhythm of salivary cortisol, plasma cortisol, and plasma ACTH in end-stage renal disease

OBJECTIVE

Patients with end-stage renal disease (ESRD) can display the features of endogenous hypercortisolism but are difficult to evaluate for Cushing's syndrome. We evaluated the circadian rhythm of plasma compared with salivary cortisol in subjects with ESRD.

DESIGN

Plasma and salivary cortisol and plasma ACTH samples were drawn frequently over 24 h in an inpatient research unit in stable ESRD subjects on daytime chronic hemodialysis (n=16) vs controls (n=8).

METHODS

Plasma cortisol was measured every 2 h from 0800 to 0600 h the following day. Salivary cortisol was measured every 2 h, except between 2400 and 0400 h (sleep time). Plasma ACTH measured in a subset of samples and C-reactive protein (CRP) was measured as a marker of a subclinical inflammatory state in all subjects.

RESULTS

ESRD subjects had a discernable circadian rhythm in plasma and salivary cortisol, but with a significantly higher nadir (1800-2400 h) compared with the controls (P=0.016-<0.001). After excluding four ESRD subjects without a normal circadian rhythm, the ESRD subjects still had higher nadir plasma and salivary cortisol and plasma ACTH compared with controls. There was no difference in the correlation of salivary and plasma cortisol in control vs ESRD subjects. ESRD subjects had higher CRP levels compared with controls.

CONCLUSIONS

ESRD subjects had increased late-night plasma and salivary cortisol and plasma ACTH levels. Late-night salivary cortisol is a reliable index of plasma cortisol in ESRD patients.

Health and immune traits of Basque and Large White pigs housed in a conventional or enriched environment

Since decades, production traits such as growth rate, feed efficiency or body composition have been drastically increased in pigs by genetic selection. Whether this selection impacted animal robustness is still unclear. In this study, we compared Large White (LW) pigs, a breed submitted to intense genetic selection for production traits, and Basque (B) pigs, a local rustic breed, reared in two different housing environments (conventional v. enriched). Adaptation to housing conditions among each breed was evaluated at the level of endocrine and immune traits. These are known to be impacted by housing conditions and breed; however, the interaction effects between genotype and environment are less described. Animals (20 per breed and housing environment) entered the experiment at 35 kg of live weight. Levels of cortisol, acute-phase inflammatory proteins, immunoglobulins and hydrogen peroxide, blood formula, lymphocyte proliferation and in-vitro cytokine expression were measured at ∼115 kg of live weight. Animals were checked for skin injuries during the growing period. At slaughter, at the average live weight of 145 kg, carcasses were examined for pathological conditions of the respiratory tract. The major result was that the two breeds exhibited differences in response to the housing environment. Among the 24 sanitary, endocrine or immune traits investigated, the housing conditions affected eight variables in both breeds (salivary cortisol at 0700 and 1900 h, severity of pneumonia at slaughter) or only in B pigs (severe skin lesions) or LW pigs (salivary cortisol at 1500 h, granulocyte numbers and lymphocyte/granulocyte ratio and lymphocyte proliferation). These observations strengthen the hypothesis that selection for high meat production level might be associated with an increased susceptibility of animals to environmental stressors.

Regulation of cortisol bioavailability--effects on hormone measurement and action

Routine assessment of the hypothalamic-pituitary-adrenal axis relies on the measurement of total serum cortisol levels. However, most cortisol in serum is bound to corticosteroid-binding globulin (CBG) and albumin, and changes in the structure or circulating levels of binding proteins markedly affect measured total serum cortisol levels. Furthermore, high-affinity binding to CBG is predicted to affect the availability of cortisol for the glucocorticoid receptor. CBG is a substrate for activated neutrophil elastase, which cleaves the binding protein and results in the release of cortisol at sites of inflammation, enhancing its tissue-specific anti-inflammatory effects. Further tissue-specific modulation of cortisol availability is conferred by corticosteroid 11β-dehydrogenase. Direct assessment of tissue levels of bioavailable cortisol is not clinically practicable and measurement of total serum cortisol levels is of limited value in clinical conditions that alter prereceptor glucocorticoid bioavailability. Bioavailable cortisol can, however, be measured indirectly at systemic, extracellular tissue and cell levels, using novel techniques that have provided new insight into the transport, metabolism and biological action of glucocorticoids. A more physiologically informative approach is, therefore, now possible in the assessment of the hypothalamic-pituitary-adrenal axis, which could prove useful in clinical practice.

Analysis of cortisol in hair--state of the art and future directions

Changes to long-term secretion of the glucocorticoid cortisol are considered to play a crucial role in mediating the link between chronic stress and the development of numerous immune system related diseases. However, obtaining valid assessments of long-term cortisol levels is difficult due to limitations of previous measurement strategies in blood, saliva or urine. This review discusses evidence on a recent methodological development assumed to provide a considerable advancement in this respect: the analysis of cortisol in hair. Being incorporated into the growing hair, hair cortisol concentrations (HCC) are assumed to provide a retrospective reflection of integrated cortisol secretion over periods of several months. Over the past years, supportive evidence has accumulated regarding several fundamental characteristics of HCC, including its validity as an index of long-term systemic cortisol levels, its reliability across repeated assessments and its relative robustness to a range of potential confounding influences. Based on this groundwork, research has now also commenced to utilise HCC for answering more specific questions regarding the role of long-term cortisol secretion in different stress and health-related conditions. The possibility of extending hair analysis to also capture long-term secretion of other steroid hormones (e.g., androgens or estrogens) provides a further intriguing prospect for future research. Given its unique characteristics, the use of hair analysis holds great promise to significantly enhance current understanding on the role of steroid hormones in psychoimmunological research.

Relationship between psychological stress and recurrent miscarriage

Stress arousal may compromise the feedback regulation of the hypothalamo-pituitary-adrenal axis, releasing stress-related biomarkers and thereby affecting establishment of pregnancy. This study examined the relationship between stress and recurrent miscarriage (RM) and the impact of stress on establishment of pregnancy. The stress status of 45 patients with unexplained RM and 40 fertile women was investigated with the Fertility Problem Inventory (FPI), Perceived Stress Scale (PSS), Positive and Negative Affect Schedule, peripheral natural killer (NK) cells and cortisol. Patients with unexplained RM had significantly higher scores on the FPI (P<0.05, adjusted OR 1.02), PSS (P<0.05, adjusted OR 1.13) and Negative Affect scale (P<0.05, adjusted OR 1.12) and lower scores on the Positive Affect scale (P<0.05, adjusted OR 0.89) than fertile controls. Patients who had live births (n=20) during the study period had significantly lower scores in the Positive Affect scale (P<0.05, adjusted OR 1.17) than those who miscarried (n=10). There was a little association between psychological stress measurements and biochemical stress measurements. These results suggest that stress is a risk factor of RM. Within women with RM, moderate stress appears to be associated with improved pregnancy outcome.

Late-night salivary cortisol for diagnosis of Cushing's syndrome by liquid chromatography/tandem mass spectrometry assay

BACKGROUND

Late-night salivary cortisol (LNSC) measurements have been increasingly used by physicians as an initial diagnostic test for evaluation of patients with clinical suspicion of Cushing's syndrome (CS). Published studies include various numbers of cases, controls and importantly, various assay methods (vast majority various immunoassays), as well as various methods to generate cut-points.

MATERIALS AND METHODS

The retrospective study evaluated the diagnostic utility of LNSC measurements in 249 patients evaluated for possibility of CS because of various clinical conditions using liquid chromatography/tandem mass spectrometry method (LC-MS/MS). CS was confirmed in 47 patients (18·9%) and excluded in 202 (81·1%) patients at the time of analysis.

RESULTS

Late-night salivary cortisol was abnormal or >2·8 nmol/l in 35 of 47 patients with CS; sensitivity of 74·5% and elevated in 20 of 202 patients who were found not to have CS; specificity 90·1%. Using receiver-operator characteristic statistics for calculation of the most optimal sensitivity and specificity, the cut-off based on this data was LNSC > 2·1 nmol/l with sensitivity of 83·0% and specificity of 84·2%.

CONCLUSION

Analysis of data at one referral institution showed somewhat limited sensitivity of LNSC for diagnosis of CS using current reference ranges.

Cushing's syndrome: diagnosis and surveillance using salivary cortisol

This short review summarizes the use of late-night salivary cortisol measurement in the diagnosis of Cushing's syndrome, in the evaluation of patients with adrenal incidentalomas, and in monitoring of post-operative patients, with a focus on the different assay methodologies currently in common use. The focus is on recent studies identified by literature searches using Ovid Medline and Google Scholar as well as analysis of several recent review articles on the topic. Measurement of late night salivary cortisol (LNSC) has an excellent sensitivity and specificity for the diagnosis of Cushing's syndrome regardless of the assay methodology used. Immunoassays have the advantage of simplicity, low cost, and small sample volume requirement, while liquid chromatography-tandem mass spectrometry has the advantage of a high specificity for cortisol and the ability to measure cortisone. The overnight dexamethasone suppression test appears to be superior to LNSC measurement in the evaluation of patients with adrenal incidentalomas. LNSC measurement is an excellent approach to monitor post-operative Cushing's disease patients for surgical failure or recurrence. Salivary cortisol is most useful as the initial test when Cushing's syndrome is suspected and for periodic patient monitoring after pituitary surgery for Cushing's disease.

Grapefruit juice and licorice increase cortisol availability in patients with Addison's disease

OBJECTIVE

Failure to mirror the diurnal cortisol profile could contribute to the impaired subjective health status in Addison's disease (AD). Some patients report benefit from the use of various nutritional compounds. The objective of this study was to investigate the impact of licorice and grapefruit juice (GFJ) on the absorption and metabolism of cortisone acetate (CA).

DESIGN

Patients (n=17) with AD on stable CA replacement therapy were recruited from the outpatient clinic at Haukeland University Hospital, Norway. They were assessed on their ordinary CA medication and following two 3-day periods of co-administration of licorice or GFJ.

METHODS

Time series of glucocorticoids (GCs) in serum and saliva were obtained, and GCs in 24 h urine samples were determined. The main outcome measure was the area under the curve (AUC) for serum cortisol in the first 2.6 h after orally administered CA.

RESULTS

Compared with the ordinary treatment, the median AUC for serum cortisol increased with licorice (53 783 vs 50 882, P<0.05) and GFJ (60 661 vs 50 882, P<0.05). Median cortisol levels in serum were also elevated 2.6 h after tablet ingestion (licorice 223 vs 186 nmol/l, P<0.05; GFJ 337 vs 186 nmol/l, P<0.01). Licorice increased the median urinary cortisol/cortisone ratio (0.43 vs 0.21, P<0.00001), whereas GFJ increased the (allo-tetrahydrocortisol+tetrahydrocortisol)/tetrahydrocortisone ratio (0.55 vs 0.43, P<0.05).

CONCLUSION

Licorice and in particular GFJ increased cortisol available to tissues in the hours following oral CA administration. Both patients and physicians should be aware of these interactions.

Challenges for the endocrine laboratory in critical illness

The endocrine laboratory must provide accurate and timely results for the critically ill patient. A number of pathophysiological factors affect assay systems for adrenal, thyroid and gonadal function tests. The effects are primarily on estimates of 'free hormone' concentration through abnormal binding protein concentrations and the effects of drugs and metabolites on hormone-protein binding. The limitations of the principal analytical techniques (immunoassay and chromatography-mass spectrometry) include drug effects, endogenous antibody interference and ion suppression. These effects are not always easily identified. Analytical specificity and standardisation result in differences in bias between assays and thus a requirement for assay specific decision limits and reference ranges. Good communication between clinician and laboratory is needed to minimise these effects. Developments in mass spectrometry should lead to greater sensitivity and wider applicability of the technique. International efforts to develop higher order reference materials and reference method procedures should lead to greater comparability of results.

Serum free cortisol as an ancillary tool in the interpretation of the low-dose 1-μg ACTH test

OBJECTIVE

Serum free cortisol, rather than serum total cortisol (TC), determines glucocorticoid activity in vivo, but how the considerable inter-subject variation in ambient serum free cortisol affects the outcome of dynamic hypothalamic-pituitary-adrenal (HPA) assessment in noncritically ill subjects is unknown.

DESIGN, PATIENTS AND MEASUREMENTS

We performed the low-dose 1-μg ACTH test in 75 subjects referred for HPA evaluation. Serum TC was determined by a chemiluminescence method, and serum free cortisol was measured by the same method following equilibrium dialysis. In a subset of these patients, salivary cortisol was also measured.

RESULTS

Mean fraction of free cortisol was 5·07 ± 4·08% (±SD; range 1·77-10·1%). Although no correlation was seen between TC and the fraction (%) of free serum cortisol, a positive correlation existed between baseline total and free cortisol (R = 0·539 P = 0·01), as well as between peak ACTH-stimulated total and free cortisol (R = 0·619; P = 0·01). There was no correlation between baseline salivary cortisol and serum free cortisol and between peak ACTH-stimulated salivary and serum free cortisol. Using the lowest attained peak serum free cortisol in subjects whose TC response to ACTH was normal (≥ 500 nM), the minimal 'pass' level for normal serum free cortisol response to 1 μg ACTH was set at 25·0 nM. Five of the 19 subjects showing subnormal TC response to 1 μg ACTH had normal serum free cortisol response.

CONCLUSIONS

Discrepancies between the peak free and TC were noted mostly for subjects whose ACTH-stimulated TC peaked between 440 and 580 nm. At this range, the measurement of serum free cortisol allows further refinement of the assessment of borderline responses to 1-μg ACTH.

Salivary cortisol can replace free serum cortisol measurements in patients with septic shock

BACKGROUND

There is a renewed interest in adrenal function during severe sepsis. Most studies have used total serum cortisol levels; however, only free serum cortisol is biologically active. The aim of this study was to determine the validity of salivary cortisol levels as a surrogate for free serum cortisol levels during septic shock.

METHODS

Fifty-seven patients with septic shock were studied to determine the correlation between total serum cortisol and salivary cortisol to free serum cortisol levels. Thirty-eight patients were included in the salivary to free serum cortisol correlation. Salivary cortisol level was tested by enzyme immunoassay. Serum total cortisol, free cortisol, and cortisol-binding globulin (CBG) levels were determined by liquid chromatography-mass spectrometry, equilibrium analysis, and radioimmunoassay, respectively.

RESULTS

The mean ± SD age was 56.6 ± 18.5 years. Fifty-seven percent were women. APACHE (Acute Physiology and Chronic Health Evaluation) II score median was 26, Simplified Acute Physiology Score II median was 61, and Sequential Organ Failure Assessment median was 13. The correlation between salivary and free serum cortisol levels was 0.79 (95% CI, 0.63-0.89; P < .0001). The correlation between free serum cortisol and total serum cortisol levels was 0.86 (95% CI, 0.78-0.92; P < .0001). The mean ± SD free serum cortisol level was 2.27 ± 1.64 μg/dL. The mean ± SD salivary cortisol level was 2.60 ± 2.69 μg/dL. The mean ± SD total serum cortisol level was 21.56 ± 8.71 μg/dL. The mean ± SD CBG level was 23.54 ± 8.33 mg/dL.

CONCLUSIONS

Salivary cortisol level can be used as a surrogate of free serum cortisol level in patients with septic shock with very good correlation. Salivary cortisol testing is noninvasive, easy to perform, and can be conducted daily.