Endocrine Abstracts

Background: Previous studies show poor consensus on the use of GH stimulation tests. Sex steroid priming and re-testing in the transition period are areas not previously surveyed. In light of more recent guidance and expert opinion, this survey aims to analyse the diagnostic processes employed in the diagnosis of GH deficiency (GHD) in the UK.

Methods: Data were collected from tertiary paediatric endocrinologists, paediatricians with a specialist interest in endocrinology, and biochemists across the UK. Surveys were distributed with support from the British Society of Paediatric Endocrinology and Diabetes and the Association for Clinical Biochemistry and Laboratory Medicine.

Results: Diagnostic tests: 48 paediatric departments and 57 biochemistry departments responded. 33% of departments used at least three different tests. Glucagon and insulin doses varied most. The frequency of sampling varied most following insulin administration.

All laboratories use a recommended chemiluminescence immunoassay with an acceptable CV. The GH peak for diagnosing GH deficiency varied (6 – 8 μg/l) across departments, most commonly 7 μg/l (35%).

Retesting: Most reported stopping GH at least one month before re-testing, most commonly with glucagon (56%), however re-testing was undertaken in a wide range of clinical scenarios suggesting non-standardised current practice.

Priming: 75% of departments use sex steroid priming, but by a range of criteria, including bone age (61%), age (50%), pubertal stage (50%) and variation in type/dose of steroid.

Conclusion: Although recognised as a contentious diagnostic test due to poor reliability, sensitivity and specificity, GH stimulation tests remain the gold standard for diagnosing GHD. Variation was found amongst all aspects of indication, protocol, assay and interpretation of GH stimulation tests between departments. Hopefully these data, together with the latest research, reviews and guidance, will encourage review of practice in the investigation, diagnosis and follow-up of these children to, over time, eventually find consensus.