Plasma free testosterone in the diagnosis of adolescent polycystic ovary syndrome.

We have employed plasma free testosterone concentrations to diagnose polycystic ovary syndrome in adolescence after demonstrating that mature plasma free androgen levels are achieved by midpuberty. Among 43 female volunteers, 10 to 16 years of age, followed up in a mixed longitudinal-cross-sectional study, we found that three (7%) had elevated plasma free testosterone levels in the absence of symptoms or signs of hyperandrogenemia. Of two who were followed up, the abnormality resolved on completion of sexual maturation in one, and in the other polycystic ovary syndrome was subsequently diagnosed. We diagnosed this syndrome in 14 adolescents as the basis of menstrual disorders associated with hirsutism, acne, or obesity. The diagnosis was based on finding elevated free testosterone values, which did not decrease after adrenal suppression by dexamethasone. Serum concentrations of luteinizing hormone were elevated in most but not all. In some of these patients further confirmation of polycystic ovary syndrome was obtained by laparoscopy or ultrasound examination. These studies demonstrate that measurement of plasma free testosterone before and after administration of dexamethasone appears to be the most sensitive single method for detecting polycystic ovary syndrome.