Validated criteria for the interpretation of a single measurement of serum cortisol in the investigation of suspected adrenal insufficiency

Morning serum cortisol role in the adrenal insufficiency diagnosis with modern cortisol assays

PURPOSE

To investigate the accuracy of cutoff values of the morning serum cortisol (MSC) using the cortisol stimulus test (CST) insulin tolerance test (ITT) and 250 mcg short Synacthen test (SST) as the reference standard tests, to better define its clinical role as a tool in the diagnostic investigation of adrenal insufficiency (AI) AI.

METHODS

An observational study was conducted with a retrospective analysis of MSC in adult patients who had been submitted to a CST to investigate AI between January 2014 and December 2020. The normal cortisol response (NR) to stimulation was defined based on the cortisol assay.

RESULTS

371 patients underwent CST for suspected AI, 121/371 patients (32.6%) were diagnosed with AI. ROC curve analysis showed an area under the curve (AUC) for MSC of 0.75 (95% CI 0.69 - 0.80). The best MSC cutoff values to confirm AI were < 3.65, < 2.35 and < 1.5 mcg/dL with specificity of 98%, 99%, and 100%, respectively. MSC > 12.35, > 14.2 and > 14.5 mcg/dL had sensitivity of 98%, 99%, and 100%, respectively, being the best cutoff values to exclude AI. Almost 25% of patients undergoing CST for possible AI had MSC values between < 3.65 mcg/dL (6.7% of patients) and > 12.35 mcg/dL (17.5% of patients), making the formal CST testing unnecessary if we consider these cutoff values.

CONCLUSION

With the most modern cortisol assays, MSC could be used as a diagnostic tool, with high accuracy to confirm or exclude AI, avoiding unnecessary CST; thus, reducing expenses and safety risks during AI investigation.

Diagnostic strategies in adrenal insufficiency

PURPOSE OF REVIEW

Adrenal insufficiency (AI) is the clinical manifestation of deficient production of glucocorticoids with occasionally deficiency also in mineralocorticoids and adrenal androgens and constitutes a fatal disorder if left untreated. The aim of this review is to summarize the new trends in diagnostic methods used for determining the presence of AI.

RECENT FINDINGS

Novel aetiologies of AI have emerged; severe acute respiratory syndrome coronavirus 2 infection was linked to increased frequency of primary AI (PAI). A new class of drugs, the immune checkpoint inhibitors (ICIs) widely used for the treatment of several malignancies, has been implicated mostly with secondary AI, but also with PAI. Salivary cortisol is considered a noninvasive and patient-friendly tool and has shown promising results in diagnosing AI, although the normal cut-off values remain an issue of debate depending on the technique used. Liquid chromatography-mass spectrometry (LC-MS/MS) is the most reliable technique although not widely available.

SUMMARY

Our research has shown that little progress has been made regarding our knowledge on AI. Coronavirus disease 2019 and ICIs use constitute new evidence on the pathogenesis of AI. The short synacthen test (SST) remains the 'gold-standard' method for confirmation of AI diagnosis, although salivary cortisol is a promising tool.

Pre-test Cortisol Levels in Predicting Short Synacthen Test Outcome: A Retrospective Analysis

Objective:

Short Synacthen tests (SSTs) are expensive, dependent on Synacthen availability, and need supervision. To reduce SST testing, we examined the utility of pre-test cortisol (Cort0) and related parameters in predicting outcome.

Design and Measurements:

We retrospectively examined the following in all SSTs; (i) Cort0 (ii) indications (iii) and time and place of testing. Receiver operated characteristic (ROC) curves were devised for Cort0 to obtain the best cut-off for outcome prediction in those who had SSTs between 8 and 10 am (Group 1) and at other times (Group 2).

Results:

Of 506 SSTs, 13 were unsuitable for analysis. 111/493 SSTs (22.5%) were abnormal. (1) ROC curves predicted – (a) SST failure with 100% specificity when Cort0 was ⩽124 nmol/L (Group 1), or ⩽47 (Group 2); (b) a normal SST with 100% sensitivity when Cort0 ⩾314 nmol/L (Group 1) and ⩾323 nmol/L (Group 2). (2) There was significant correlation between Cort0 and 30-minute cortisol (r_s = 0.65-0.78, P  < .001). (3) Median Cort0 was lower in those who failed SSTs compared to those who passed (147 vs 298 nmol/L respectively, P  < .001). (4) SST failure was commoner in Group 1 vs 2 (P = .001). (5) There was no difference in outcome between out-patient and inpatient SSTs. (6) SST failure was most common for ‘steroid related’ indications (39.6%, P  < .001).

Conclusions:

This study indicates that (1) Cort0 ⩾ 323 (Group1) and ⩾314 nmol/L (Group 2) predicted a normal SST with 100% sensitivity; (2) Using these cut offs 141/493 (28.6%) tests may have been avoided; (3) supporting evidence should be considered in those with a lower pre-test predictability of failure.

Improving the Interpretation of Afternoon Cortisol Levels and SSTs to Prevent Misdiagnosis of Adrenal Insufficiency

BACKGROUND

Adrenal Insufficiency (AI), especially iatrogenic-AI, is a treatable cause of mortality. The difficulty in obtaining 9 am cortisol levels means samples are taken at suboptimal times, including a substantial proportion in the afternoon. Low afternoon cortisol levels often provoke short Synacthen tests (SSTs). It is important that this does not lead to patients misdiagnosed with AI, exposing them to the excess mortality and morbidity of inappropriate steroid replacement therapy.

METHODS

This retrospective study collected 60 178 cortisol results. Medical records, including subsequent SSTs of initial cortisol results measured after midday were reviewed.

RESULTS

Receiver operating characteristic analysis (area under the curve: 0.89) on 6531 suitable cortisol values showed that a limit of <201.5 nmol/L achieved a sensitivity and specificity of 95.6% and 72.6%, while a limit of <234 nmol/L had a sensitivity of 100% and a specificity of 59.5%. Out of 670 SSTs, 628 patients passed. Of these, 140 would have otherwise failed if only their 30-min cortisol was assessed without the 60-min value. A 30- and 60-min SST cortisol cutoff of 366.5 nmol/L and 418.5 nmol/L, respectively, can achieve a sensitivity of >95% on the Abbott analyser platform.

CONCLUSION

An afternoon cortisol >234 nmol/L excludes AI on Abbott analyser platforms. In patients who have an afternoon cortisol <234 nmol/L, including both 30- and 60-min SST cortisol values prevents unnecessary glucocorticoid replacement therapy in 22.3% of individuals in this study. The Abbott analyser SST cortisol cutoffs used to define AI should be 366.5 nmol/L and 418.5 nmol/L at 30 and 60 min, respectively. All patients remained well subsequently with at least 1-year longitudinal follow-up.

Postoperative adrenal insufficiency in Conn's syndrome-does it occur frequently?

Primary aldosteronism (PA) is the most frequent form of endocrine hypertension. Recently, frequent clinically significant adrenal insufficiency after adrenalectomy in subjects with PA has been reported, which may make the early postsurgical management difficult. We retrospectively searched for possible adrenal insufficiency in subjects who underwent adrenalectomy for PA and have measured cortisol in the early postoperative course. We included subjects with confirmed diagnosis of PA who underwent either posture testing (blood draw at 06:00 and 08:00) and/or adrenal venous sampling (AVS) (blood draw between 08:00 and 09:00) and have also measured cortisol after surgery (cortisol measured approximately at 07:00). Cortisol was measured by immunoassay. In this study, we identified 150 subjects (age 48.5 ± 10.3 years) with available cortisol values in the early postoperative course (median [25th percentile, 75th percentile]) 6 [5,6] days. Postoperative cortisol values (551 ± 148 nmol/l) were normal and significantly higher, compared to preoperative standing cortisol values (404 ± 150 nmol/l; (P < 0.001) and AVS cortisol values (493 ± 198 nmol/l; P = 0.009), and did not significantly differ from preoperative supine cortisol values. Postsurgical cortisol values were not different among subjects with or without abnormal dexamethasone suppression test or elevated urinary free cortisol pre-surgery, and were significantly higher in subjects with abnormal diurnal cortisol variability compared with subjects with normal diurnal variability. No patient presented with adrenocortical crisis in the later follow-up. In conclusion, postoperative cortisol values did not indicate any suspicion of possible adrenal insufficiency. To exclude possible adrenal insufficiency, it may be sufficient to measure morning cortisol in the early postoperative course.

Should patients with Phosphomannomutase 2-CDG (PMM2-CDG) be screened for adrenal insufficiency?

PMM2-CDG is the most common congenital disorder of glycosylation (CDG) accounting for almost 65% of known CDG cases affecting N-glycosylation. Abnormalities in N-glycosylation could have a negative impact on many endocrine axes. There is very little known on the effect of impaired N-glycosylation on the hypothalamic-pituitary-adrenal axis function and whether CDG patients are at risk of secondary adrenal insufficiency and decreased adrenal cortisol production. Cortisol and ACTH concentrations were simultaneously measured between 7:44 am to 1 pm in forty-three subjects (20 female, median age 12.8 years, range 0.1 to 48.6 years) participating in an ongoing international, multi-center Natural History study for PMM2-CDG (ClinicalTrials.gov Identifier: NCT03173300). Of the 43 subjects, 11 (25.6%) had cortisol below 5 μg/dl and low to normal ACTH levels, suggestive of secondary adrenal insufficiency. Two of the 11 subjects have confirmed central adrenal insufficiency and are on hydrocortisone replacement and/or stress dosing during illness; 3 had normal and 1 had subnormal cortisol response to ACTH low-dose stimulation test but has not yet been started on therapy; the remaining 5 have upcoming stimulation testing planned. Our findings suggest that patients with PMM2-CDG may be at risk for adrenal insufficiency. Monitoring of morning cortisol and ACTH levels should be part of the standard care in patients with PMM2-CDG.

Recalibration of thinking about adrenocortical function assessment: how the 'random' cortisol relates to the short synacthen test results

Background

The short synacthen test (SST) is the most commonly performed investigation to assess adrenal function. Appropriate criteria for when an SST is performed are subject to debate. We investigated how random serum cortisol levels relate to SST response.

Methods

We examined random cortisol measurements taken between 04.40–23.55 p.m. results of SST baseline and 30-/60-min cortisol performed over 12 months (225 SSTs) at Salford Royal Hospital. Serum cortisol was measured on the Siemens Centaur Analyser.

A 30–60-min cortisol concentration of ≥450 nmol/L defined a pass; 350–449 nmol/L defined borderline.

Results

Patients only proceeded to SST if random cortisol was <400 nmol/L. For those not on corticosteroids for at least 2 weeks, 42/43 (97.7%) cases with random cortisol concentration of ≥200 nmol/L had an SST ‘pass’. The relation was less clear with corticosteroid treatment (19/35 cases; 54%).

For those not taking glucocorticoid treatment (including inhaled/topical corticosteroids) in the previous 2 weeks, 91.8% of SSTs were pass/2.7% borderline/5.5% fail. For those on steroids, 51.9% of SSTs were a pass/11.4% were borderline.

In relation to the postsynacthen cortisol pass cut-off of ≥450 nmol/L, in 15/207 (7.2%) of cases, the 60-min cortisol was ≥450 nmol/L (adequate adrenocortical function), but 30-min cortisol was below this. In all cases where the 30-min cortisol did indicate a pass (i.e. was ≥450 nmol/L) the 60-min cortisol was also ≥450 nmol/L.

Conclusion

Our findings suggest that if the random cortisol level is ≥200 nmol/L, regardless of the time of day and the person was not taking corticosteroid treatment in the previous 2 weeks, SST may not be needed. Our data also suggests that 60-min cortisol retains utility.

Should Pediatric Endocrinologists Consider More Carefully When to Perform a Stimulation Test?

INTRODUCTION

Pediatric endocrinology rely greatly on hormone stimulation tests which demand time, money and effort. The knowledge of the pattern of pediatric endocrinology stimulation tests is therefore crucial to optimize resources and guide public health interventions. Aim of the study was to investigate the distribution of endocrine stimulation tests and the prevalence of pathological findings over a year and to explore whether single basal hormone concentrations could have saved unnecessary stimulation tests.

METHODS

Retrospective study with data collection for pediatric endocrine stimulation tests performed in 2019 in a tertiary center.

RESULTS

Overall, 278 tests were performed on 206 patients. The most performed test was arginine tolerance test (34%), followed by LHRH test (24%) and standard dose Synachthen test (19%), while the higher rate of pathological response was found in insulin tolerance test to detect growth hormone deficiency (81%), LHRH test to detect central precocious puberty (50%) and arginine tolerance test (41%). No cases of non-classical-congenital adrenal hyperplasia were diagnosed. While 29% of growth hormone deficient children who performed an insulin tolerance test had a pathological peak cortisol, none of them had central adrenal insufficiency confirmed at low dose Synacthen test. The use of basal hormone determinations could save up to 88% of standard dose Synachthen tests, 82% of arginine tolerance + GHRH test, 61% of LHRH test, 12% of tests for adrenal secretion.

CONCLUSION

The use of single basal hormone concentrations could spare up to half of the tests, saving from 32,000 to 79,000 euros in 1 year. Apart from basal cortisol level <108 nmol/L to detect adrenal insufficiency and IGF-1 <-1.5 SDS to detect growth hormone deficiency, all the other cut-off for basal hormone determinations were found valid in order to spare unnecessary stimulation tests.

Diagnostic performance of morning serum cortisol as an alternative to short synacthen test for the assessment of adrenal reserve; a retrospective study

OBJECTIVE

The short synacthen test (SST) is widely used across the UK to assess adrenal reserve. The main objective of our study was to determine the morning serum cortisol level that will predict adrenal insufficiency (AI) thus reducing our reliance on SST.

DESIGN

This was a single centre retrospective study of 393 SST tests measuring 0 and 60 min cortisol levels after administration of 250 μg of synacthen (synthetic ACTH).

PATIENTS AND METHODS

All the SST tests for patients suspected of primary or secondary AI between April 2016 and October 2018 were included in this study. We used serum to determine circulating cortisol by a newer generation competitive electrochemiluminescence immunoassay (ECLIA) (Roche Diagnostics). A post-ACTH cortisol response of ≥420 nmol/L at 60 min was considered adequate to rule out AI. The data were analysed to ascertain the relationship between 0 min and 60 min serum cortisol.

RESULTS

A total of 393 SST results were included in this study. Overall, a total of 332 (84.5%) subjects achieved sufficient serum cortisol level at 60 min, while 61 subjects (15.5%) showed insufficient response. Using the logistic regression, we determined that a morning basal serum cortisol level of ≥354 nmol/L was able to predict normal adrenal function with 100% sensitivity. We were unable to find a lower cut-off value below which SST will not be required. By using this proposed cut-off point, approximately 37% of the SSTs tests could be avoided.

CONCLUSIONS

Basal morning serum cortisol can be safely used as a first step in the evaluation of patients with suspected AI. This will enhance the number of patients being screened for this condition.

Diagnostic performance of basal cortisol level at 0900-1300h in adrenal insufficiency

OBJECTIVE

An ACTH stimulation test is the standard diagnostic test for adrenal insufficiency (AI). We aimed to investigate the diagnostic performance between serum morning (0800 h) cortisol and serum basal (0900-1300 h) cortisol levels and determine the proper cut-off point to facilitate AI diagnosis to reduce the number of tests.

METHODS

A six-year retrospective study was performed in a tertiary care medical center. We identified 416 patients who had undergone either low (LDT) or high dose (HDT) ACTH stimulation outpatient tests. AI was defined as a peak serum cortisol level of <500 nmol/L at 30 or 60 minutes after LDT or HDT. The associations between AI and serum basal and morning cortisol levels were demonstrated by logistic regression model. Diagnostic performance was evaluated by ROC analysis.

RESULTS

Of the 416 patients, 93 (22.4%) were categorized as having AI. The adjusted area under the curve (AUC) for the basal cortisol level for the diagnosis of AI was significantly higher than that for the morning cortisol (0.82 vs 0.69, p <0.001) level. The proposed cut-off values for the basal cortisol were <85 nmol/L (specificity 99.7%) and >350 nmol/L(sensitivity 98.9%). By using these proposed cut-off points, approximately 30% of the ACTH stimulation tests could be eliminated.

CONCLUSION

The serum basal cortisol level with the proposed cut-off points were considered as an alternative option for diagnosis of AI. Utilizing the serum basal cortisol level can facilitate AI diagnosis as it is convenient, is not a time-specific test and has a high diagnostic performance.