A study is planned to check stool occult blood positivity using hemoccult test among a group of paicipants aged 50 - 75 years. The test is repeated if result is positive. No repeating if the test is negative. What is the effect on sensitivity and specificity?
SCREENING TESTS IN One test (after +ve result) after other Both tests applied together COMBINED SERIES PARALLEL SENSITIVITY Decreases Increases SPECIFICITY Increases Decreases PPV Increases Decreases NPV Decreases Increases
Sensitivity increases specificity decreases
Sensitivity decreases specificity increases
Sensitivity unchanged specificity increases
Sensitivity increases specificity unchanged
Screening