'Negative At 3, Positive At 5': Dr. Dave Hnida Warns COVID Tests Have Limits

(CBS4) - Coloradans are flocking to COVID-19 testing sites all across the state as new ones are opened. In some cases, people are trying to get tested before spending Thanksgiving with loved ones.

CBS4 Medical Editor Dr. Dave Hnida warns a negative test is not a clean bill of health.

"If it's positive, it's positive and you know you've got an issue," he told CBSN Denver's Makenzie O'Keefe, "but a negative test is really not a guarantee everything is going well."

Hnida said it's important to understand that a test is a snapshot of what's going at the time you get the test done.

"There are circumstances where people are infected but they have very low levels of the virus in their body," he explained, "so low a test won't show up positive. Yet over the course of hours after that test is done, the virus in the body multiplies so much that a person does become infected."

"Even a test at 3 p.m. could be negative, by 5 p.m. it could be positive."

Hnida also pointed out you have a test on a certain day and you can get infected in the hours or days afterwards leading up to your dinner plans.

He also said the tests may not be as accurate as we think, especially if you don't have symptoms and are counting on the results of a rapid test.

"Really the bottom line is that we really are at the place where testing is not a replacement for masks, social distancing and staying within your own household ... for Thanksgiving."