Padronização de valores de captação tiroidiana com 123I

Abstract

RESUMOCom o objetivo de padronizar valores de referência para captação tiroidiana (CAPTIR) com 123 I, analisamos 475 pacientes que realizaram dosagens de T4 livre e TSH e exames de CAPTIR 24h após a administração de 123 I. Separamos os pacientes em 3 grupos: hipertiróideo, normal e hipotiróideo, de acordo com os resultados do T4 livre e TSH. Calculamos as médias e os desvios-padrão (DP) dos valores de captação, realizamos testes t não-pareados e calculamos curvas ROC para definir os melhores valores de CAPTIR para separar os grupos. As médias e DP dos valores de captação foram: hipertiróideo (36,5% ± 16,5%), normal (14,4% ± 5,48%) e hipotiróideo (13,7% ± 7,5%). O teste t não-pareado mostrou diferença significativa entre os grupos hipertiróideo e normal (p< 0,01), sem diferença significativa entre os grupos normal e hipotiróideo (p= 0,55 To establish references for thyroid 24h 123 I uptake value (TUV), we reviewed 475 patients who had freeT4 and TSH dosages, and TUV measured 24h after the administration of 123 I. The patients were separated in 3 groups: hyperthyroid, euthyroid and hypothyroid, according to thyroid hormone results. The mean and standard deviation (SD) of the TUVs were calculated for each group. We used the unpaired T test to compare the means and ROC curves to evaluate the best TUV to separate the groups. The mean and SD of TUVs for the groups were: hyperthyroid (36.5% ± 16.5%), euthyroid (14.4% ± 5.48%) and hypothyroid (13.7% ± 7.5%). The unpaired T test showed statistically significant difference between hyperthyroid and euthyroid groups (p< 0.01). There was no significative difference between hypothyroid and euthyroid groups (p= 0.55). The 23% TUV has the best sensitivity (80%) / specificity (93%) ratio to separate hyperthyroid from euthyroid groups. There was not a good TUV to separate euthyroid form hypothyroid groups. In conclusion, it can be established 23% as the optimal superior limit for the normal uptake values. However, it was not possible to establish a suitable inferior limit, due to the expressive overlay of TUVs of hypothyroid and euthyroid groups.