Estimation of testosterone (T) levels in women is required to make a differential diagnosis of hyperandrogenism, including that to rule out androgen-producing tumors. The problems of the sensitivity and specificity of T determination methods are associated with the extraction of steroids from plasma or serum, which is labor consuming and expensive. The relatively inexpensive direct methods widely clinically applied to estimate the levels of T just in the serum without its previous extraction are unsuitable for women and children to use. The foregoing is confirmed in the paper by two clinical observations.