Study compares diagnostic value of three growth hormone tests

The insulin tolerance test (ITT) is the most specific and accurate method for diagnosing growth hormone deficiency (GHD), but the arginine stimulation test (ArST) offers comparable accuracy with fewer side effects, according to a study.

The retrospective study included 138 patients with idiopathic short stature and 135 patients with GHD treated with GH for 1 year. Patients with GHD were divided into subgroups based on their height standard deviation score (SDS) gains: those with gains ≥0.5 (group IIa) and those with gains <0.5 (group IIb).

Group IIa had significantly lower insulin-like growth factor binding protein-3 (IGF-BP3) levels and higher BMI SDS at baseline compared to other groups. After 1 year of treatment, group IIb demonstrated poorer growth outcomes, including lower height SDS gains, slower growth velocity, and reduced predicted adult height SDS. The study found correlations between bone age, BMI SDS, IGF-BP3, and height SDS gain in patients with GHD.

Among the stimulation tests, ITT exhibited the highest specificity (72.3%) and accuracy (86.6%), followed by ArST, which showed slightly lower specificity (64.7%) but comparable accuracy (87.2%). L-dopa had the lowest specificity (50.3%) and accuracy (70.3%). While ITT was the most reliable, ArST caused fewer side effects.

Reference
Chang SH, Kim CJ. Comparison of growth hormone stimulation tests in prepubertal children with short stature according to response to growth hormone replacement. Ann Pediatr Endocrinol Metab. 2024;29(5):316-324. doi: 10.6065/apem.2346234.117. Epub 2024 Oct 31. PMID: 39506345; PMCID: PMC11541089.