[Efficient diagnosis of hyperthyroidism, rationally justified?]

The value of various diagnostic tests for recognizing hyperthyroidism was assessed in 285 patients. The prevalence of hyperthyroidism was 33% altogether: 21.8% diffuse hyperthyroidism (Graves' disease and disseminated autonomy) and 11.2% autonomous adenoma. A negative TRH-test was found in 29.5% of the euthyroid patients, 11.4% in patients younger and 40.7% in patients older than 50 years. In one patient with thyrotoxicosis the TRH-test was positive in the beginning. In 29% of the patients with diffuse hyperthyroidism and in 50% of the patients with hyperthyroid autonomous adenoma only one hormone level was elevated (T3, T4 or FT4). The radioiodine test contributed primarily to the final diagnosis in 1.6% of diffuse hyperthyroidism and in 6.2% of hyperthyroid autonomous adenoma. Because of its high sensitivity the TRH-test remains the basic test in the diagnosis of thyrotoxicosis. The diagnostic value of T3 and FT4 is equivalent with slight advantages of FT4. In order to lower costs, the total T4 measurements can, and the radioiodine test has to be, omitted. However, it ought to be kept in mind that if only the TRH test and T3 and FT4 are included in the diagnostic study, the final diagnosis is not substantiated adequately in one third of the patients with thyrotoxicosis.