Which laboratory test is expected to be abnormal in a suspected case of polycystic ovary syndrome in a young woman?

In a suspected case of polycystic ovary syndrome (PCOS), an abnormal level of serum total testosterone is expected due to the hormonal imbalances characteristic of the condition. PCOS is often associated with hyperandrogenism, where the ovaries produce an excess of androgens, such as testosterone. This elevated level can lead to various symptoms, including irregular menstrual cycles, hirsutism (excess hair growth), and acne.

Testing for total testosterone provides crucial information in confirming a diagnosis of PCOS, as many women with this condition exhibit higher levels of circulating testosterone compared to those without it. The elevated androgens is a key feature of the syndrome and assists in distinguishing PCOS from other conditions that may cause reproductive and metabolic symptoms.

While insulin-like growth factor 1, serum prolactin, and thyroid-stimulating hormone are important in the overall assessment of a patient's hormonal profile, they are not specifically indicative of PCOS. Elevations or abnormalities in these tests are more aligned with other medical conditions, rather than being a hallmark of PCOS itself.