Two-hour Adrenocorticotropic Hormone Test: Accuracy in the Evaluation of the Hypothalamic- Pituitary-Adrenocortical Axis

Abstract

Summary subnormal basal and stimulated levels. Thus the ACTH test didThe inter-and intraindividual variations of response to an iv not diierentiate this state from ACTH deficiency.bolus of tetracosactide (0.25 mgl1.73 m2) were studied, and a definitive diagnostic 2-hr test was established. The test was Speculation given to 179 subjects: hypopituitary, prednisone-treated nephrotics, patients with the autoimmune polyendocrinopathyWhen the Witeria for a in the 2-hr iv ACTH candidinsis syndrome (APECS), and reference subjects. ~t was test have been carefully established, this test will serve as a repeated in 62 cases and the total of 84 test pairs was analyzed. definitive procedure for the diagnosis and follow-up of states me test was either at 8-9 AM or at 10-11 AM, 2 hr associated with ACTH deficiency, as well as in primary diseases after the injection of insulin for an insulin test. Thirty subjects of the adrenal cortex. Like the other ACTH tests, however, it had both the A~H test and the i n s u l i n -~~~H test. capillary will not diierentiate with certainty between primary and secondblood samples for fluorometric determination of plasma cortisol ary adrenOcOrtical were taken 1 , 2 , and 3 hr after the injection.The distributions of the basal and stimulated levels were positively skewed, and log transformation of the data gaveIn the diagnosis of adrenocortical failure, stimulation with a clearly more appropriate statistics. In most subjects the single dose of exogenous ACTH with determination of the level was highest 2 hr &ter the injection. There was no swifiresponse in plasma cortisol level has partly replaced longer tests. cant difference in the response to ACTH whether it was Bven The shortest test in wide use consists of an im or iv injection of alone or in the insulin-ACTH test. All the poststimulation the 1-24 peptide (20,24,38) and determination of plasma cortisol levels showed a positive interindividual correlation with cortisol before and 30 min after the injection (4, 11, 18, 37, 39, the basal levels, and all the increments a negative interindividual 41). However, this test is not accurate, and it is used mainly as correlation with the basal levels.a screening procedure, with variable criteria for a normal reIn repented tests, the intraindividunl variation in the responses sponse. In none of the 1 to 3-hr tests so far introduced have was &redly correlated with the level of the response, and this criteria for a normal response been adequately established on a correlation could be removed by dividing the intrapair difference theoretically sound basis (23, 3 1-33, 35, 42). We have made a in the values of the parameters by the sum of the values for careful evaluation of a 2-hr ACTH test, which we here propose percentage of intrapair difference (PIPD). m e SD of the for a definitive diagnostic procedure. A preliminary report has distribution of PIPDs was used for an index of precision. The 2-appeared (28). hr cortisol level was substantially more precise than either the basal level or the increment. In an...

The Diagnosis and Staging of Hypocortisolism in Progressing Autoimmune Adrenalitis

“…Basal and 2-h cortisol levels show no intra-individual dependence and are thus independent measures of cortisol secretory capacity. In contrast, the increment is totally dependent on the intra-individual variations in the basal and 2-h levels; hence, the increment should not be taken as the sole parameter of the test result (13). Surprisingly, we observed subnormal basal cortisol levels in only a few patients with far ., R. …”

“…Normal response criteria for the 2hAT were based on results for 30 healthy children aged 2.8-18.4 years. Because both the 2-h plasma cortisol levels and the 2-h increments showed a strong inter-individual dependence on the basal level, a normal result is most accurately defined by an area formed on a plot of 2-h level verslls basal level by the 95% confidence limits for the estimation of 2-h levels for given basal levels, and by the 95% confidence limits for the basal level (7-36 pgJdl; 0.19-1 .OO pM) (13). An increment of ~3 .…”

“…The 2hAT (13). the insulin test (14), and the vasopressin test (1 5) were performed as previously described.…”

Maternal Glucocorticoid in Unplanned Premature Labor. Controlled Study on the Effects of Betamethasone Phosphate on the Phospholipids of the Gastric Aspirate and on the Adrenal Cortical Function of the Newborn Infant

“…This test has been well standardized for clinical use (12). Our data show that the responsiveness of the adrenal cortex at 24 hr of age is not impaired, even if the mother has received twice 12 mg of betamethasone during 24 hr before delivery.…”

Peri‐operative steroid supplementation

“…In one study a third of normal subjects failed to demonstrate an increase greater than 200 nmol.l ¹1 [47]. Furthermore, the cortisol increment is inversely proportional to the basal cortisol value and hence smaller increases are obtained in the morning when endogenous concentrations are already high [48,49]. It has been suggested that calculation of the incremental increase in serum cortisol has no value [50].…”