What is a major limitation of preventive screening highlighted by USPSTF?

• A. It has no harms
• B. It is expensive but harmless
• C. Potential harms from false positives, overdiagnosis, and unnecessary procedures
• D. It always detects disease early

Answer: (C)

The main idea here is that screening tests, while designed to find disease before it causes symptoms, can cause harm as well. The major limitation USPSTF highlights is that screening can lead to false positives, overdiagnosis, and unnecessary procedures.

False positives occur when a test suggests disease when there isn’t any, leading to anxiety and a cascade of follow-up tests, biopsies, or surgeries that carry their own risks. Overdiagnosis means detecting conditions that would never have caused problems during the person’s life, so treating them causes unnecessary side effects without real benefit. These downsides must be weighed against the potential benefits of earlier detection.

That’s why the other statements aren’t correct: screening can involve harm; it isn’t guaranteed to be harmless or free of cost, and it does not always detect disease early.