We offer both screening and diagnostic tests. Learn the difference and why it matters

Screening and Diagnostic Tests: Know the Difference

Since the beginning of the COVID-19 pandemic, the world has become increasingly aware of the importance of testing in healthcare. However, it is important to know the difference between diagnostic testing and screening. Both are important to healthcare management, but screening and diagnostic tests have different purposes and may need to be used together to create an overall picture of your health.

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What’s the difference between screening and diagnostic testing?

Put simply, screening tests are designed to identify whether you are at increased risk to be affected by the condition being screened. Diagnostic tests are designed to provide a definitive “yes” or “no” diagnosis for the condition being tested.

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Type of TestPossible ResultsProvides a Diagnosis?

Screening test (e.g. mammogram, cholesterol measurements, Pap smear, colonoscopy, fecal blood test, NIPS (NIPT), carrier screening or hereditary cancer screening)

Increased risk, decreased risk, screen positive, screen negative, higher or lower chance than baseline/initial riskNo. You may require follow-up testing based on your doctor’s recommendation, which may include specialty referral and diagnostic confirmation
Diagnostic test (e.g., tissue biopsy, amniocentesis)Positive: Person or pregnancy is affected
Negative: Person or pregnancy is unaffected
Yes. Diagnostic testing provides confirmation of the condition. You should receive follow-up consultation to review results and get support for appropriate medical management

What do my screening test results mean?

A positive result on a screening test indicates you have an increased risk for the condition and is NOT a definitive diagnosis. Your physician or healthcare provider will likely order a diagnostic test to confirm the result.

A negative screening result does not guarantee you are unaffected by the condition being screened. It is important that any result is evaluated within the context of your clinical and medical history.

Understanding screening and diagnostic test performance

Screening test performance is measured using four clear attributes: sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

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No screening test is 100% definitive

Screening tests, by definition, can result in false positives and false negatives. The most sensitive tests will have a low number of false negatives, and the most specific ones will have a low number of false positives.

Your healthcare provider can help answer your questions about screening test results and help you decide next steps.

We are a trusted resource of screening and diagnostic testing

Screening tests get the conversation started. Combined with confirmatory diagnostic tests, they can help you understand what is going on with your health. It is worth noting that screening recommendations differ by age and sex assigned at birth, so download our checklist that outlines the types of screenings you need.

If you use one of our many screening options—several of which you can shop for directly on Labcorp OnDemand—make sure you share your results with your doctor or primary healthcare provider so they can best determine the right path forward for you and your overall health.