Which hormonal investigations are recommended for the diagnosis of hirsutism in primary care?

Recommended hormonal investigations for diagnosing hirsutism in primary care include measuring serum total testosterone and 17-hydroxyprogesterone levels.

Serum total testosterone should be measured to assess androgen excess; a level above 4.0 nanomol/L warrants referral to endocrinology, with urgent referral if levels exceed 6–7 nanomol/L due to the possibility of an androgen-secreting tumour.

Elevated 17-hydroxyprogesterone levels (greater than 6 nanomol/L) suggest non-classical congenital adrenal hyperplasia and require further investigation.

These hormonal tests help exclude underlying endocrinopathies such as adrenal hyperplasia, Cushing syndrome, or androgen-secreting tumours.