Diagnosing Growth Hormone Defficiency: caveats, & cut-offs

madman

Super Moderator
Growth hormone deficiency (GHD) diagnosis in children and adults is complex due to varying clinical markers and challenges in testing accuracy. GH replacement therapy is crucial for affected patients. Testing requires a thorough medical history, physical examination, and targeted biochemical testing. Random serum GH measurements are unreliable for screening except in neonates. GH stimulation tests may be necessary but can be imprecise, with caveats in interpreting results. This article offers a comprehensive overview of GHD diagnosis accuracy, cut-offs, and testing challenges in both age groups.




Key takeaways:

*Caution is needed in interpreting GH stimulation tests due to their non-physiological nature and test variability.

*Different GH cut-offs based on provocative agents.

*Priming with sex steroids for peripubertal GHD testing to reduce false positives.

*Some tests are costly, prolonged, and carry risks; reproducibility concerns exist.

*Lack of normative data for specific etiologies of adult GHD.

*Pediatric guidelines discourage reliance on GH stimulation tests alone for diagnosing GHD in children.

*Adult GHD complicated by increased susceptibility to central obesity.

*BMI-specific cut-off important in testing patients with GHD.





GH stimulation tests should be carefully considered based on clinical suspicion. For pediatric patients, combining test results with other measurements provides a comprehensive clinical picture for proper evaluation and treatment. The Insulin Tolerance Test (ITT) remains the gold standard, while other tests like GHRH plus arginine, GST, clonidine, and macimorelin are reasonable alternatives. Macimorelin is attractive due to its ease of use and accuracy. However, challenges include cost and accessibility. Improving assay harmonization and technology may enhance diagnostic accuracy. More studies in various populations are needed to refine GH cut-offs. A structured approach is crucial for accurate GHD diagnosis and GH replacement.
 

Attachments

Table 1 Causes of GHD and types of GHD that requires testing for adult GHD.
Screenshot (26263).webp
 

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Estradiol (E2)

A form of estrogen produced from testosterone. Important for bone health, mood, and libido. Too high can cause side effects; too low can affect well-being.

DHT

Dihydrotestosterone is a potent androgen derived from testosterone. Affects hair growth, prostate health, and masculinization effects.

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The biologically active form of testosterone not bound to proteins. Directly available for cellular uptake and biological effects.

Scientific Reference

Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men. J Clin Endocrinol Metab. 2010 Aug;95(8):3955-64.

DOI: 10.1210/jc.2010-0102 | PMID: 20534765 | PMCID: PMC2913038

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