COVID-19 false positives are setting off a chain reaction of issues

OAKLAND, Calif. - With more and more people getting tested for COVID-19, some are wondering how accurate the test results are.

You have no choice but to assume that your coronavirus test results will be completely accurate, then you can act accordingly.

An East Bay mother, who wanted no publicity, e-mailed KTVU writing that her husband was exposed to a person infected with COVID-19 at his work.

So, she set up test for him, her child and herself, getting the most commonly used "PCR" test.

UC Berkeley Public Heath Epidemiologist Dr. Arthur Reingold says PCR tests have an excellent track record. "These tests are, I would say, are very specific. That is, they really do not have many false positives."

But, her family's results all came back positive, setting off a chain reaction of concern and testing for friends, other family members, co-workers, her child's daycare staff, the other daycare families, along with lost work and a delayed surgery.

Two days later, the lab that processed the PCR test called back to say its machine was contaminated and that only the husband was positive.

That says Reingold, is not the test's fault.

"I'm not sure I would call that a false positive as opposed to a laboratory error," said Reingold.

PCR's have very few false negatives, mostly because the virus has not attained a detectable level or reached a place in the patient's body where the sample is taken. 

Another test, the antibody test, reveals only if you were exposed in the past and are not currently infected. It does not prove you are immune.

"There are many people doing those and I would say their significance remains to be determined," said Reingold,.

Another kind of test, an antigen test, is cheaper, faster and similar to flu and strep throat tests.

But antigen tests result in many false negatives in infected people.

"They're fast. If they're positive, we're pretty sure they're a real positive. They're are not a lot of false positives but they do have a lot of false negatives," said Reingold.

Since this was a lab error, not a doctor's error, attorney Terry Anderlini says it's not medical malpractice. But, the lab may be liable for negligent testing, and all that followed stemming from the erroneous results.

"All of their out-of-pocket damages or wage loss of pain and suffering, inconvenience, emotional distress and the damages that are reasonable to expect," said Anderlini.

Where it may not be liable is if the results were wrong, but within the scientific margin of error, provided the test was done correctly.