Medical Tests: False Positives and Negatives

When a test is performed to detect a disease, there are four possible outcomes.

  • If a test indicates that a patient has a disease that the patient does indeed have, this is called a true positive.1
  • However, if the test indicates that a patient has a disease when she does not, it is called a false positive.1
  • If the test indicates the patient is disease-free, and this is indeed the case, it is called a true negative.1
  • Finally, if the test indicates the patient is healthy when in fact the patient has the disease, we call this a false negative.1

Click on the image below to view a documentary on false positives and negatives.

On the next page you can learn more about medical tests and watch our documentary on sensitivity and specificity.

  • 1. a. b. c. d. Segen, Joseph C., Wade, Josie."The Patient's Guide to Medical Tests."Infobase Publishing, 2002.