dromlakhani Indicate GH stimulation testing for suspected growth hormone deficiency
STEP 1 — Gather Information
Collect clinical history (symptoms of GHD, pituitary disease, prior hormone deficiencies), baseline IGF-1, BMI, and assess for contraindications; if suspicion of GHD remains, proceed to stimulation testing.
STEP 2 — Rule In / Rule Out
Determine if clinical suspicion of GHD is present (e.g., symptoms + pituitary history + low IGF-1); if yes, rule in for GH stimulation testing; if no, rule out and consider alternative diagnoses.
STEP 3 — Classify or Stratify
Perform a GH stimulation test (insulin tolerance, glucagon, or GHRH‑arginine) and classify peak GH response using BMI‑specific cutoffs (<3 µg/L for BMI <25, <2 µg/L for BMI 25‑30, <1 µg/L for BMI >30) to define deficiency or sufficiency.
STEP 4 — Decide
If peak GH is below the BMI‑adjusted cutoff, diagnose GHD and consider initiating GH replacement therapy; if peak GH is above the cutoff, consider alternative diagnoses and avoid GH replacement.
Clinical Guardrails / Mimics / Pitfalls
Do not rely on random or single GH measurements; ensure fasting and testing before 10 AM; treat known central hypothyroidism before testing to avoid false‑normal GH response; avoid testing during acute/subacute illness; adjust cutoffs for obesity; discontinue estrogen if it interferes with GH assay.
Concrete Clinical Example
A 50‑year‑old man with prior pituitary apoplexy, decreased libido, and low IGF‑1 undergoes an insulin tolerance test; peak GH is 1.8 µg/L (BMI 28, cutoff <2 µg/L), diagnostic of GHD; GH replacement initiated at 0.3 mg/day.
Source: Hormonal Replacement in Hypopituitarism in Adults: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2016, DOI:10.1210/jc.2016-2118