Mass-screening programs for the population are being applied increasingly for the detection of inapparent disease, those diseases in which there is a latent or silent period and in which early diagnosis and treatment may result in improved outcome.
In tuberculosis screening programs, routine premarital testing for venereal disease, and programs for the early detection of cancer, considerable progress has been made. The ultimate goal of such measures is complete diagnosis, effective treatment, and, hopefully, eradication for some diseases. The chief difficulty in attaining this goal is the frequent inability to capture the total population at risk in the course of screening.
There are certain advantages in programs for the detection of inherited metabolic diseases, such as phenylketonuria. The vast majority of infants in the United States are born in hospitals, and, for a short postnatal period, they constitute a captive population. Infants affected with such metabolic disturbances show minimal evidence