A new test has been devised to detect lung carcinoma. The levels of the enzyme corresponding to diseased states are being determined. A random number of smokers are sorted (ie, with and without lung carcinoma) and the corresponding enzyme levels are determined. At what cut-off value (ie, enzyme level) will the number of false negatives be the highest?

Question

A new test has been devised to detect lung carcinoma.  The levels of the enzyme corresponding to diseased states are being determined.  A random number of smokers are sorted (ie, with and without lung carcinoma) and the corresponding enzyme levels are determined.  At what cut-off value (ie, enzyme level) will the number of false negatives be the highest?

Quizplus · Accepted Answer

False negatives (FN) pertain to the patients who have a negative test result despite actually having the disease (ie, those who are incorrectly labelled as healthy or without disease). When the cut-off level of a diagnostic test is raised (eg, from point A up to point B; or from any of the points listed up to point E), the FN will also consequently increase. (Choices A, B, C and D) Cut-off points A, B, C, D will result in lower false negative values. Educational objective: False negatives will increase when the cut-off level of a diagnostic test is raised.

A New Test Has Been Devised to Detect Lung Carcinoma