A positive control is added (spiked) into a test specimen. The test results of the specimen alone and the spiked mixture are negative. What does this most likely indicate?

Question

Quizplus · Accepted Answer

The fact that the positive control is negative, despite being spiked with a known positive sample, suggests that an inhibitor is present in the test specimen that is preventing detection of the target analyte. This is further supported by the negative test results of the specimen alone. Therefore, the most likely explanation is that the specimen contains an inhibitor that is affecting the accuracy of the test.

A Positive Control Is Added (Spiked) into a Test Specimen