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OGTT for acromegaly — SCE Endocrinology MCQ

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HardEndocrine emergencies/dynamic testsOGTT for acromegalySCE Endocrinology

A woman has unequivocally raised age-adjusted IGF-1 on two measurements. During a 75 g oral glucose test, nadir GH is 0.8 micrograms/L using a modern sensitive assay. MRI shows a 9 mm pituitary lesion. What is the best interpretation?

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Correct answer: C — Assay-aware interpretation remains compatible with acromegaly

Explanation lettering: E = shown as B · B = shown as E

C is correct. Historical GH cut-offs around 1 microgram/L and lower modern assay thresholds must be interpreted with assay, BMI, sex and oestrogen status. Persistently high IGF-1 plus a nadir 0.8 on a sensitive assay and concordant lesion remains compatible with acromegaly and warrants specialist integration or repeat testing, not exclusion by an obsolete 2 microgram/L rule. MRI neither overrides biochemistry nor diagnoses function alone.

Reference: https://pmc.ncbi.nlm.nih.gov/articles/PMC6979446/