Screening for a disease is application in-

. screening is defined as "the search for unre4cognized disease or defect by means of rapidly applied tests,examinations,or other procedures in apparently healthy individuals.detection programmes should be restricted to thoseconditions in which there is considerable time lag between disease onset and the usual time of diagnosis.in this period there are usually a number of critical points which determine both the severity of the disease and the success of any treatment in reversing the disease process. ref:park&;s textbook of preventive and social medicine,22 nd edition,pg no127