To understand the process of screening , it should be clear that screening is not usually diagnostic and in most cases is followed by appropriate investigative procedures to confirm the results. The process of screening starts by  selecting the population, followed by performing a screening procedure to classify individuals into either apparently healthy or affected. For the apparently healthy individuals, regular screening at fixed intervals is recommended. The  apparently affected group is sent for further evaluation by a subsequent diagnostic procedure. Appropriate intervention is started among those with confirmed diagnosis while individuals who prove to be unaffected are asked to repeat the screening test at fixed intervals.