RESUMEN
OBJECTIVE: To report the experience, obstacles, and strategies of screening for congenital hypothyroidism. SETTING: Newborns in Mexico. METHODS: Thyroid stimulating hormone (TSH) was measured by enzyme immunoassay using commercial kits in 1,140,364 newborns. RESULTS: There were 464 positive cases, of whom 299 (64.4%) were girls. 236 (50.9% showed ectopic nodules, 202 (43.5%) thyroid agenesis, 21 (4.5%) dyshormonogenesis, and 5 (1.1%) an unclassified goitre. The false positive rate was 0.024% and there were 11 false negative results. Currently, 600,000 (26%) of the 2,300,000 newborns are screened. This percentage has been increased in recent years by taking samples from cord blood and will be increased further by starting congenital hypothyroidism screening at social security units and by midwives screening infants born at home. CONCLUSIONS: Mental retardation in infants in developing countries can be reduced by neonatal screening, and carefully planned strategies can steadily extend the benefits of screening.
Asunto(s)
Hipotiroidismo Congénito , Hipotiroidismo/diagnóstico , Tamizaje Neonatal , Recolección de Muestras de Sangre/métodos , Reacciones Falso Positivas , Femenino , Sangre Fetal/química , Humanos , Hipotiroidismo/epidemiología , Recién Nacido , Estudios Longitudinales , Masculino , México/epidemiología , Tamizaje Neonatal/métodos , Tamizaje Neonatal/organización & administración , Tamizaje Neonatal/normas , Prevalencia , Distribución por Sexo , Glándula Tiroides/anomalías , Tirotropina/sangreRESUMEN
A newborn screening program for congenital hypothyroidism (CH) and phenylketonuria (PKU) was conducted in 140 163 infants from the Federal District and the states of Mexico and Tlaxcala. These children were born mainly in hospitals for the non-insured population, although some were social security beneficiaries. Their filter-paper blood TSH and phenylalanine concentrations were determined 48 hours after birth. The frequency of CH was 1:1 797, with a 95 per cent confidence interval of 1:1 470 to 1:2 315, and was quite similar in the different types of hospitals. Only two PKU cases were found, for a frequency of 1:70 082, with a 95 per cent confidence interval of 0 to 1:4 762. This work demonstrates the feasibility of newborn screening programs in Mexico, identifies the problems to be solved in order to achieve a wide coverage and establishes the high frequency of CH in the Mexican population.