Alessandro Burelli

Measurement of serum free thyroid hormone concentrations: an essential tool for the diagnosis of thyroid dysfunction

Free thyroid hormones (free thyroxine, FT4, and free triiodothyronine, FT3) represent a more useful index of thyroid status than total thyroid hormones, because the latter are influenced by variations of thyroid hormone-binding proteins, especially T4-binding globulin (TBG). Thus, increased serum total T4 (TT4) and, in many instances, T3 (TT3) concentrations are encountered in euthyroid subjects with TBG excess, familial dysalbuminemic hyperthyroxinemia and transthyretin-associated hyperthyroxinemia, while decreased serum TT4 and TT3 levels are associated with TBG deficiency: under these circumstances, measurement of serum FT4 and FT3 levels correctly establishes the diagnosis of euthyroidism. In cases of suspected hyperthyroidism, a diagnostic strategy can be suggested based on serum FT3 (and TSH) measurement, since FT4 may occasionally be elevated, also in euthyroid subjects, e.g., in patients under chronic amiodarone or L-T4 treatment. When hypothyroidism is suspected, the most reliable test appears to be FT4 (together with TSH), because FT3 may still be normal in patients with subclinical or mild thyroid failure. In any case, it is essential that reliable free thyroid hormone assays be used, which are devoid of methodological limitations responsible for artifactual results under particular circumstances, such as thyroid hormone-binding protein abnormalities, pregnancy and nonthyroidal illness.

Serum PSA levels are not affected by the menstrual cycle or the menopause, but are increased in subjects with polycystic ovary syndrome

Background/aims: Prostatic specific antigen (PSA) is the most specific prostatic tumor marker in man. Recently, PSA has been detected in a variety of tissues and fluids in women, and its determination suggested as a marker of hyperandrogenism. However, precise information about the physiology of PSA in females is not available. The goal of this study was to assess serum concentrations of PSA in healthy pre-menopausal women (healthy pre-menopausal group), menopausal women (menopause group) and patients with polycystic ovary syndrome (PCOS group). Methods: PSA, androgens, LH, FSH, 17-β-estradiol (E2), progesterone (Pg) were assessed in 40 post-menopausal women, 35 fertile controls and 35 women with PCOS. Results: No significant difference in PSA concentrations could be demonstrated in different phases of the menstrual cycle in healthy pre-menopausal group and between pre- and post-menopausal groups. No correlations could be demonstrated between serum PSA levels and the following parameters: age, body mass index (BMI), LH, FSH, E2, testosterone (T), DHEAS, and SHBG, both in pre- and post-menopausal women. Significantly higher PSA levels (median=14 pg/ml) were found in the PCOS group compared to both pre-menopausal (median=5 pg/ml) and menopausal (median= 5 pg/ml) groups (p<0.05). Conclusions: only minor fluctuations of serum PSA concentrations are observed in healthy pre- and post-menopausal women, while serum level is higher in PCOS, and therefore PSA can be considered a suitable marker of female hyperandrogenism.