6th June 2025

A 27-year-old black woman presents with asymptomatic darkening of skin on her neck folds.

A 27-year-old black woman presents with asymptomatic darkening of skin on her neck folds. She also admits to recently gaining weight of 9kg. On physical examination, she is noticeably obese and there are thickened, velvety, hyperpigmented plaques on her posterior neck. You suspect a diagnosis of acanthosis nigricans. What is the most important investigation to do in this patient?

Select the SINGLE most appropriate option from the list below. Select ONE option only.