Screening for condition recommended when-
Low case fatality rate
Diagnostic tools not available
No effective treatment available
Early diagnosis can change disease course because of effective treatment
Ref:Parks 23rd edition pg 136. Screening is carried out in the hope that earlier diagnosis and subsequent treatment, orably alters the natural history of the disease in a significant propoion of those who are identified as "positive". Note: We don&;t do screening when the disease has a low case fatality ratio. Diagnostic tools/tests must be made available before doing a screening test. Otherwise it will be in vain. Effective treatment should be available prior to doing a screening test. Also Refer p. 135. Table 1.
Screening