TORONTO — Finding the right test to screen for hyperandrogenism in hirsute women can be difficult because of a lack of reliability among affordable assays, Dr. Robert L. Rosenfield said at the annual meeting of the Androgen Excess Society.
Testing for hyperandrogenism is generally recommended when hirsutism is moderate or severe (a score of greater than 15 on the Ferriman-Gallwey scale) or if there is any degree of hirsutism accompanied by risk factors for virilizing neoplasm or polycystic ovary syndrome.
Total testosterone should be the initial screening assay, because testosterone is the major circulating androgen. However, testing is not clearly better than clinical judgement if laboratory validity is not ensured, as is often the case, said Dr. Rosenfield, professor of medicine and pediatrics at the University of Chicago.
Ideally, free testosterone would be measured, but this assay is less standardized than total testosterone assays, he said. As a result, the reliability of the assay in general laboratories is less consistent. A free testosterone determination by a specialty laboratory is indicated for patients with risk factors for tumor or polycystic ovary syndrome, even if the initial total testosterone is normal.
Follow-up is an important part of the management of a mildly hirsute patient with no central obesity and no menstrual dysfunction, Dr. Rosenfield said. If a patient with mild hirsutism develops other associated symptoms, then she can be tested. But overtesting is not cost-effective and can yield both false-positive and false-negative results.
Dr. Rosenfield receives research support in the form of grants from the U.S. Public Health Service and Quest Diagnostics, maker of a testosterone assay.
The Endocrine Society also recently weighed in on the issue of measuring testosterone (JCEM 2007;92:405–13). In a position paper released in February, the society recommended that laboratory proficiency testing be based on the ability to accurately measure a sample containing a known concentration of testosterone, not simply on agreement among peers using the same method.
The position statement concluded that free testosterone is the most useful, clinically sensitive marker of hyperandrogenemia in women when calculated using high-quality testosterone and sex hormone-binding globulin assays with well-defined reference intervals.
The group also noted that direct testosterone assays perform poorly in women and children, who have low levels of testosterone concentrations, and that these assays should be avoided.
In an effort to advance the field, the Endocrine Society and the Centers for Disease Control and Prevention are collaborating on the establishment of standards to validate the performance of laboratory assays of serum testosterone levels.