Screening for congenital hypothyroidism (CH) among Filipino newborn infants. Philippine Newborn Screening Study Group

Abstract

From June 1996 to June 1998 a total of 62.841 newborn infants were screened for congenital hypothyroidism with thyroid stimulating hormone assay as a primary test. The method used was an immunofluorescent assay using the DELFIA TSH Kit on dried blood specimens collected by heelprick on filter paper. All infants with TSH values greater than 20 microU/ml were retested. If the results remained abnormally high, confirmatory testing was done by radioimmunoassay. All infants who were confirmed to be hypothyroid were referred to pediatric endocrinologists for initial management. The overall weighted incidence of congenital hypothyroidism obtained in this study was 0.000277 (95% CI; 0.000122 - 0.000432) or 1:3,610 which may be higher than that reported by most screening programs worldwide. The recall rate was 0.16%. The higher recall rate may be explained by early testing in a number of cases and by the possibility of iodine deficiency in some of the mothers. On the basis of the results of this study, we would recommend (1) screening on a greater number of infants to verify the incidence of CH and (2) establishing normal TSH values at different hours of life to improve our recall rate.