dromlakhani Apply BMI-controlled cutoffs for peak GH assessment in GHD evaluation
STEP 1 — Gather Information
Measure patient's weight and height to calculate BMI (kg/m²). Obtain peak GH value from a validated stimulation test (insulin tolerance, glucagon, or GHRH‑arginine) performed under fasting conditions and before 10 AM.
STEP 2 — Rule In / Rule Out
Determine BMI category: <25, 25–30, or >30. Compare peak GH to BMI‑specific cutoff: <25 → 5 µg/L, 25–30 → 4 µg/L, >30 → 3 µg/L. If peak GH ≤ cutoff, rule in possible GHD; if > cutoff, rule out GHD.
STEP 3 — Classify or Stratify
Classify as growth hormone deficiency (GHD) when peak GH is at or below the BMI‑adjusted cutoff; otherwise classify as non‑deficient.
STEP 4 — Decide
If GHD is confirmed, proceed to evaluate contraindications and consider GH replacement therapy. If not deficient, investigate alternative causes of symptoms and avoid GH therapy.
Clinical Guardrails / Mimics / Pitfalls
Do not apply a universal 5 µg/L cutoff regardless of BMI; avoid testing during acute/subacute illness or within 24 h of glucocorticoid dose; ensure assay specificity (GH, not IGF‑1); recognize that obesity may blunt GH response, necessitating lower cutoffs.
Concrete Clinical Example
A 52‑year‑old woman with BMI 28 undergoes glucagon stimulation test; peak GH is 3.6 µg/L. BMI 25–30 cutoff is 4 µg/L; peak GH ≤ cutoff → GHD diagnosed; consider GH replacement after pituitary hormone review.
Source: Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2016, DOI:10.1210/jc.2016-2118
TODO: consider adding scripts/calc.py for the ata-gh-bmi-cutoff calculator