[Recent parameters for diagnosis of challenging thyroid gland disorders: consequences for diagnosis and therapy].

The recognition of the peripheral state of thyroid hormones is often disturbed by factors like pharmacological interferences or non-thyroidal illness, especially borderline hyperthyroidism may often be misjudged. Some serological parameters like the measurement of sex hormone binding globulin, precollagen-peptid I and III, osteocalcin, angiotensin converting enzyme and fibronectin are often elevated in such states and can indicate thyrotoxicosis of certain tissues. Such thyrotoxicosis-like alterations can be shown also in TSH-suppressive therapy with levothyroxine. In contrast to early publications there is obviously only a minor influence of levothyroxine treatment on bone metabolism, where a decrease of bone mass is less probable. Recent developments of sensitive and specific modifications in estimating antibodies against thyroidal peroxydase in recognizing thyroid autoimmune disease and of thyroglobulin in the follow-up of differentiated thyroid cancer are becoming important tools in clinical medicine.