Estrone is primarily derived from metabolism of androstenedione in peripheral tissues, especially adipose tissues. Individuals with obesity have increased conversion of androstenedione to Estrone leading to higher concentrations. In addition, an increase in the ratio of Estrone to Estradiol may be useful in assessing menopause in women. Estrone levels may be elevated in patients with polycystic ovarian syndrome and endometriosis. Tests may be used to aid in the diagnosis of an ovarian tumor, Turner syndrome, and hypopituitarism. In males, it may help in the diagnosis of the cause of gynecomastia or in the detection of estrogen-producing tumors.