The 'yield' of a screening programme is MOST directly influenced by which of the following?

• A The sensitivity of the test alone
• B The specificity of the test alone
• C Prevalence of undetected disease in the screened population ✓
• D Cost of the screening test

Explanation

Yield — the number of cases detected per number screened — is most directly influenced by the prevalence of previously undiagnosed disease in the target population. Even a highly sensitive test will yield few new cases if the disease is rare or has already been largely diagnosed. This is why screening is most productive when targeted to high-prevalence subgroups (e.g., diabetic retinopathy screening for diabetics rather than the general population). Sensitivity affects whether existing cases are found, but prevalence determines how many cases are available to be found.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.