[New strategy for thyroid function testing]

The authors used a new protocol, based upon a supersensitive TSH assay, to examine the thyroid status of 1720 patients. Based upon the serum hormone levels, the patients were divided into different clinical groups. The biochemical relationship between the different hormone levels, and the rate of occurrence of various thyroid diseases were studied. 76.1% of the new patients hadn't received any previous treatment. 15.5% of those patients who had received treatment had hyperthyroidism, while 8.4% of those had hypothyroidism. 76% of the new patients, 38.3% of those who had hyperthyroidism, and only 29.7% of those who had hypothyroidism, were euthyroid. Undetectable TSH levels (< 0.03 mU/L) where observed in 51.8% of the new hyperthyroid patients, and in 33.8% of those who had subclinical hyperthyroidism. Similar results were obtained with those who had been previously treated for hyperthyroidism. The new protocol has the following advantages: it's more convenient to the patients, it's quick, it's economical. With this method it is possible to reduce the assays per patient by 31%. The algorithm was supplemented with results of free hormone levels. By doing this the authors were able to measure free-T4 and T3 hormone levels of 150 more patients. According to the authors, the free-T4 test is more informative than the free-T4-index, especially in the border-line cases and in treated hyperthyroidism. Primarily the free-T3 test is most necessary when examining patients treated with methimasol.