Análisis comparativo entre la TSH de tercera generación y la prueba de estimulación con TRH en pacientes con hipertiroidismo, hipotiroidismo y sujetos normales

Abstract

The analysis of third generation TSH became a test of choice for differentiation between patients with real hyperthyroidism and those with suppressed TSH levels associated with other pathology. First and second generation tests were characteristically unable to make that differentiation. The functional sensitivity (0.001 mUI/L) and analytic sensitivity (0.002 mUI/L) of the third generation studies permit an improvement. With the hypothesis that this test could be as sensitive as TRH stimulation test, we studied 111 people, 46 with hypothyroidism, 29 with hyperthyroidism and 36 healthy controls. Basal samples were obtained and 200 ug of TRH were administred IV and then samples of serum were obtained at 30, 60 and 90 minutes afterwards. TSH measurements were done by the system IMMULITE (DPC) which uses a chemoluminisence reader with vertical centrifugation. Statistically significant findings were found between basal TSH levels and those at 30.60.90 min post TRH stimulation and the differences were most significant in the hyperthyroid patients. Our findings suggest that the TSH third generation test has the same diagnostic sensitivity for hyperthyroidism when levels are below 0.44 mUI/L than that of the TRH stimulation test.