Comparação entre duas estratégias para a detecção precoce do hipotiroidismo congênito Comparison between two strategies for the precocious detection of congenital hypothyroidism

OBJETIVO: Comparar em recém-nascidos (RN) duas estratégias diferentes para o rastreamento do hipotiroidismo congênito (HC), a dosagem primária de TSH no sangue colhido do cordão umbilical (método 1) e a dosagem primária de T4 no sangue colhido por punção de calcanhar no 2º dia de internação (método 2). MÉTODOS: Os autores compararam as duas estratégias em 10.000 RN. Dosaram o TSH por método imunofluorimétrico sensível em papel de filtro e o T4 por radioimunoensaio em papel de filtro. A coleta de sangue do calcanhar foi realizada no 2º dia de vida RESULTADOS: Os dois programas diagnosticaram todos os casos de HC nos RN (4 casos, 1/2.500 RN). O índice de rechamada por coleta inadequada foi nulo no método 1 e de 8,5% (850 RN) no método 2. O índice de reconvocação para confirmação de resultados foi de 0,06% (6 RN) no método 1 e de 2,25% (225 RN) no método 2; quando este método incluía também a dosagem suplementar de TSH, o índice baixou para 1,63% (163 RN). CONCLUSÃO: Os dados dos autores evidenciam a superioridade técnica da coleta de sangue a partir do cordão umbilical em relação à punção de calcanhar, assim como da dosagem primária de TSH em relação à de T4, uma vez que apresentam índices muito menores de reconvocação.<br>OBJECTIVE: Compare two different strategies in newborn screening for congenital hypothyroidism, primary TSH in the umbilical cord blood (method 1) and primary T4 in blood collected from the heel in the 2nd day of life (method 2). METHODS: We compared both strategies in 10,000 newborns, measuring TSH by a sensitive immunofluorimetric assay and T4 by a radioimmunoassay. RESULTS: Both strategies detected all cases of hypothyroidism (4 cases, 1/2,500 newborns). The recalling index owing to insufficient amount of blood to perform the assays was zero in method 1 and 8.5% (850 newborns) in method 2. The recalling index for confirmation of the results was 0.06% (6 newborns) in method 1 and 2.25% (225 newborns) in method 2; when method 2 included supplementary TSH, the recalling index was reduced to 1.63% (163 newborns). CONCLUSION: Our data indicate the technical superiority of the umbilical cord blood compared to heel and primary TSH compared to primary T4 in the neonatal thyroid screening for congenital hypothyroidism

Comparison Of Two Strategies For The Early Detection Of Congenital Hypothyroidism [comparação Entre Duas Estratégias Para A Detecção Precoce Do Hipotiroidismo Congênito.]

OBJECTIVE: Compare two different strategies in newborn screening for congenital hypothyroidism, primary TSH in the umbilical cord blood (method 1) and primary T4 in blood collected from the heel in the 2nd day of life (method 2). METHODS: We compared both strategies in 10,000 newborns, measuring TSH by a sensitive immunofluorimetric assay and T4 by a radioimmunoassay. RESULTS: Both strategies detected all cases of hypothyroidism (4 cases, 1/2,500 newborns). The recalling index owing to insufficient amount of blood to perform the assays was zero in method 1 and 8.5% (850 newborns) in method 2. The recalling index for confirmation of the results was 0.06% (6 newborns) in method 1 and 2.25% (225 newborns) in method 2; when method 2 included supplementary TSH, the recalling index was reduced to 1.63% (163 newborns). CONCLUSION: Our data indicate the technical superiority of the umbilical cord blood compared to heel and primary TSH compared to primary T4 in the neonatal thyroid screening for congenital hypothyroidism.442818