How reliable are rapid tests? Doctor explains when you should and shouldn't depend on the results

Jessica Harrington Image
Thursday, January 20, 2022
How reliable are rapid tests? Dr. explains when to depend on results
Dr. Kenny Banh with UCSF Fresno COVID Equity Project says while the rapid test is a great tool, it's only effective when used correctly.

FRESNO, Calif. (KFSN) -- When it comes to getting tested for Covid-19 there are two main tests you can get, a PCR test or a rapid test.

The two tests look for different things, but overall, the PCR test is most effective, according to health officials.

Dr. Kenny Banh with UCSF Fresno COVID Equity Project says while the rapid test is a great tool, it's only effective when used correctly.

"We've actually ran out of rapid home tests already," said Karla Delorbe, who was waiting for a PCR test at UCSF's testing site across from Fashion Fair Mall.

Delorbe said her family was able to get some rapid tests from Fresno Unified School District, but they've already used those.

They can't find the tests at the store and they've signed up for the free ones offered by the federal government, but they're not expected to ship out for 7 to 12 days.

"We've ordered some online, but it kind of just takes time and I've been off work for, I think, it's been two weeks actually," Delorbe said.

Sharon Wilson said she's been dealing with a cough.

She used a rapid test and it came back negative.

"I was told by many people that it will put out more negatives than it will positives. Positives are for sure and negatives aren't for sure," Wilson said.

That's why Wednesday, she was in line at the UCSF Fresno Clinic to get a PCR test and see if she has COVID or something else.

Dr. Banh said Wilson did the right thing because rapid tests are less effective for diagnosis than a PCR test.

"If you have symptoms and you have a negative rapid, you should make the presumption that there's still a high likelihood you have COVID and you should treat yourself as COVID," said Dr. Banh.

If a rapid test is positive, however, Dr. Banh says people don't necessarily need a PCR test. Just make sure to report the results to your local health department.

Dr. Banh says rapid tests are extremely effective in determining when someone can return to work after testing positive for COVID.

He said most people are less infectious after five days. If a rapid test also comes back negative, you're likely safe to return to work.

"Is it perfect? Absolutely not. That's actually why we do still recommend for you to take precautions, right? When you come back, we're talking about coming back to work, but making sure you're wearing masks and that you're protecting yourself and the others around you," said Dr. Banh.

As a reminder, the federal government is giving out four free tests per household.

Your insurance must also reimburse you for eight rapid tests a month.

Dr. Banh says although critics may say these tests are coming too late, he says it's still good to prepare.

He says cases are still going up in Fresno County and no one knows what's ahead.