Health economic analysis of the neonatal screening program in Japan.

In Japan, a nationwide mass screening system for neonatal metabolic diseases was established in 1977. This system consisted of screening programs for five main congenital metabolic diseases, including phenylketonuria (PKU). To evaluate the efficiency of the mass screening system, a cost-benefit analysis of the screening program for PKU (as a typical case in Japan) was carried out. The costs of the detection and the treatment program were compared with the projected benefit (avoided costs) that results from prevention of the mental retardation associated with the disorders due to PKU. Costs and benefits were discounted at an annual rate of 7%. Assuming that the incidence of PKU was 1/80,500 and the total number of infants screened was 1.2 million, net benefits for the screening program were $283,000, and the cost-benefit ratio was 1:2.5. The sensitivity analysis for the incidence of PKU showed that the cost-benefit ratios exceeded one.