“Wellness testing can improve health and improve lives by finding health problems even before symptoms occur.”
- Dr. Deborah Sesok-Pizzini, chief medical officer of Labcorp Diagnostics
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 can help save lives, but screening and diagnostic tests have different use cases and may need to be used together to create an overall picture of your health.
What are the key differences between screening and diagnostic tests?
1) It’s all about the signs and symptoms
We all know the key signs that we’re ill. We call them “symptoms” or “signs,” and they’re our body’s way of telling us something is wrong. Screenings and diagnostic tests initially differ based on their intended users and whether they’re symptomatic or not.
Screening tests are intended for asymptomatic (showing no or disguised symptoms) people, whereas diagnostic tests are intended for those showing symptoms in need of a diagnosis. Often, they are used together: a screening test is first performed to see if your health is on track, and a diagnostic test is then performed to either confirm or eliminate potential results.
2) Slightly different goals
What makes screening tests so valuable is their ability to detect risk. The goal of screening is to detect diseases or issues earlier, provide surveillance and help reduce the risk of disease. Though screening tests may detect irregularities or potential issues, they may not provide answers. If there is need for further diagnosis, that’s where diagnostic tests are used.
What makes diagnostic tests so valuable is their accuracy and specificity when it comes to results. An easy way to remember the key purpose of a diagnostic test is in the word itself: diagnosis. The end result of a diagnostic test is to diagnose an issue or problem.
3) Simplicity of use
Screening tests tend to be less invasive than diagnostic ones—and they are usually simpler to perform. In some cases, you’re able to get the results right at home as well. This is one of the reasons why more direct testing options have become available in the past few years.
For example, rapid antigen (screening) and even PCR tests with at-home collection (diagnostic) tests have become global conversation pieces during the COVID-19 pandemic. Given that all the patient needs are a nasal swab for collection, testing fluid and a testing strip, these kinds of tests can be purchased over the counter and conducted at home.
Some tests, however, must be performed by a licensed healthcare professional due to the more invasive or more complicated nature of the test.
Furthermore, it is vital to understand that a positive result in a screening test usually requires a more accurate diagnostic test to confirm diagnosis.
To put it another way, screening tests get us in the ballpark, and diagnostic tests let us know the score (even if it’s 0-0). Both are crucial tools in determining one’s overall health. Here are some examples of screening tests and how a diagnostic test is used as a follow up.