Principles and Practice of Screening for Disease.

The concept of screening procedure that can identify individuals in early or presymptomatic stages of disease has been discussed for some years. Wilson and Jungner have presented comprehensive review of subject of screening and an appraisal of current state of knowledge. Screening has been defined as the presumptive identification of unrecognized disease or defect by application of tests, examinations, or other procedures which can be applied rapidly. Screening tests sort out apparently well persons who probably have disease from those who probably do not. A screening test is not intended to be diagnostic. Persons with positive or suspicious findings must be referred to their physicians for diagnosis and necessary treatment. Screening is intended to be rapid and relatively inexpensive, and, as authors say, it implies a relatively simple (though not necessarily unsophisticated) method of case finding. In this day of existing excessive