Screening for minimal hypothyroidism

Preview

As we all know, serum thyroxine and triiodothyronine values can be misleading if the patient is pregnant, takes estrogen (especially birth control pills), or has another condition that alters the concentration of thyroxine-binding proteins. Therefore, to be useful, any screening test for thyroid dysfunction must measure free hormone. But which test is better, the free thyroxine index or the relatively new free thyroxine radioimmunoassay? Dr Szpunar and colleagues investigated this question by comparing these tests in 98 patients.