Extremely high follicle-stimulating hormone with normal ovarian function.
Yu Chen, Jana Bubar, Chelsey Flemming et al.
✦ AI-curated · Sources linked
Case in brief
A 34-year-old woman with normal menstrual cycles and ovarian function presented with an unexpectedly high follicle-stimulating hormone (FSH) level between 100-200 IU/L. Imaging ruled out pituitary tumors, and a dilution study suggested assay interference. Following IgG depletion, FSH levels normalized to 20.2 IU/L, indicating the presence of macro-FSH.
What made this case unusual
The case highlights the presence of macro-FSH, which can lead to misleadingly high immunoassay results despite normal ovarian function.
Diagnostic / clinical pearl
Clinicians should consider the possibility of macro-FSH in patients with elevated FSH levels and normal ovarian function, as it can mimic true hypergonadotropic conditions.
Why it matters
Understanding macro-FSH is crucial for accurate interpretation of hormone assays, preventing misdiagnosis and inappropriate management in reproductive health.