UCHealth doctor questions reliability of rapid COVID-19 testing

Posted at 9:29 PM, Nov 12, 2020
and last updated 2021-01-05 16:34:57-05

AURORA, Colo. — A UCHealth University of Colorado Hospital doctor in Aurora says rapid testing for the novel coronavirus should not be trusted.

"There is an enormous presence across Colorado of tests that are unreliable," says Dr. Richard Zane, Chair of Emergency Medicine at UCHealth University of Colorado Hospital in Aurora.

UCHealth, Denver Health, and Centura Health all tell Denver7 they do not use rapid testing at their hospitals.

The state acknowledges five types of COVID-19 testing:

  • PCR: Considered highly sensitive and specific. These usually use nasal or throat swabs, but some companies provide PCR tests using saliva or cheek swabs.
  • Antigen tests: These are not as sensitive as PCR tests. Negative results should be confirmed with a PCR. They typically use a nasal or throat swab
  • Antibody tests: These tests can’t be used for diagnosis, but can help determine if someone previously had the virus and developed antibody tests. These tests can sometimes detect other viruses and create false positives. These are blood tests and can be helpful to determine how a virus is spreading in a community.
  • Abbott ID NOW rapid: These can sometimes cause a false negative result. Anyone who receives a negative result from an Abbott test should confirm that result with a PCR. These can be used most effectively if people are tested repeatedly. For instance, these would be useful for healthcare workers who need repeated tests. These use a nasal or throat swab.
  • Abbott BinaxNOW: This is a Point of Care rapid antigen test that detects COVID-19 antigens in a nasal swab sample. It detects active infections using lateral flow technology and does not require any instrumentation to process.

The two to focus on is PCR testing and antigen testing, referred to as rapid testing.

"There’s a very good chance that the chance of a false negative is higher than a true negative. Meaning it could give you very unreliable results essentially telling you, you don’t have COVID when you may have COVID simply because of the characteristics of the test," Dr. Zane says of antigen testing.

When asked about the reliability of rapid COVID-19 testing, the Colorado State Joint Information Center told Denver7 in a statement:

"While rapid antigen tests are most reliable when individuals are symptomatic, if they are used in environments where there is frequent testing, they can be effective even when individuals are asymptomatic."