Can a cancer screening test be wrong?

Yes, a screening test can be wrong. All screening tests have risks, and two of them are false results.

• A false-positive result shows there is cancer when there really is not. It can cause anxiety and is usually followed by more tests and procedures, which also have risks.
• A false-negative result shows there is no cancer when there really is. A person who gets a false-negative result may delay seeking medical care even if they have symptoms.

Some screening procedures can also cause other problems, such as bleeding. This is why it helps to understand a test's benefits and harms and to talk them over with your healthcare provider before deciding whether it is right for you.