ESPE Abstracts (2022) 95 P1-11

ESPE2022 Poster Category 1 Adrenals and HPA Axis (52 abstracts)

Low-dose ACTH Stimulation Test: Comparison of Cortisol Response at 30, 40, and 60 Minutes

Busra Gurpinar Tosun 1 , Hazal Arikan 2 , Serap Turan 1 , Abdullah Bereket 1 & Tulay Guran 1

1Marmara University, School of Medicine, Department of Pediatric Endocrinology and Diabetes, Istanbul, Turkey; 2Marmara University, School of Medicine, Department of Pediatrics, Istanbul, Turkey

Background: Low-dose adrenocorticotropic hormone stimulation test (LDST) is commonly used for evaluating the adequacy of hypothalamo-pituitary-adrenal axis functions. However, there is still no standardization between protocols used in different centres.

Objective: To contribute to the optimal time of highest cortisol response in the LDST in children.

Design: A prospective study of LDST resultsperformed on children with clinical suspicion of adrenal insufficiency.

Method: Cortisol concentrations were measured at baseline, 30, 40, and 60 minutes after intravenous administration of 1 μg tetracosactide. Basal cortisol levels were also assessed by using liquid chromatography-mass spectrometry (LC-MS/MS). Adrenal insufficiency was defined as a stimulated cortisol level <18.1 μg/dL (500 nmol/L).

Results: 135 patients (61girls, mean age 9.98±5.93 years) were included. Cortisol response was adequate at any time point in 80.7% (n=109) of patients. In the case of a single measurement after stimulation, 62.9% (n=85) of the patients had an adequate response at minute, 72.6% (n=98) at minute, and 70.4% (n=95) at 60 minute (P=0.04). In the case of one measurement at the minute, 8 patients (7.3%) who had an adequate response at minute, would have been misdiagnosed. In this condition, delta cortisol (0 to 40) value above 9.3 μg/dL reduces the probability of LDST result being false-negative by a negative predictive value of 95.5%. The threshold basal cortisol value predicting a negative LDST result in the immunoassay method was determined as >6.5 μg/dL (69.2% sensitivity/74.3% specificity) and >6.1 μg/dL (59.1% sensitivity/78% specificity) by LC-MS/MS method (P = 0.0001).

Table 1: The probabilities of LSDT yield at 30, 40, and 60 minutes after administration of tetracosactide
  LDST Pass (n) Number of Patients Who Would Need Additional Sample to Prevent One False Positive LDST Result, n Sensitivity by whole test, Probability LDST Pass Changes, %
30 min in addition to 0 85 24 78%
40 min in addition to 0 98 11 90%
60 min in addition to 0 95 14 87%
40 min in addition to 0 and 30 101 8 93%
60 min in addition to 0 and 30 102 7 94%
60 min in addition to 0 and 40 106 3 97%

Conclusions: In the LDST, sampling at the 40th and 60th minutes after stimulation minimizes the false-positive LDSTs, and in the case of a single measurement, the minute sampling reduces false-negativity compared to the and minutes.

Volume 95

60th Annual ESPE (ESPE 2022)

Rome, Italy
15 Sep 2022 - 17 Sep 2022

European Society for Paediatric Endocrinology 

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