Copyright © 2020 Albuquerque Journal
Testing to see who has antibodies to the coronavirus has begun in New Mexico, but questions remain about how to use the results and what they actually mean.
“This keeps me up at night a little bit,” said Dr. David Grenache, chief scientific officer for TriCore Reference Laboratories.
State and health officials said last week that antibody tests would soon be available. The test detects whether a person’s blood contains coronavirus antibodies – proteins the body makes in response to the virus. A positive result would indicate the person has already been exposed to the virus.
TriCore is working to validate its testing procedures and plans to roll out the platform Monday in Albuquerque and elsewhere. Christus St. Vincent Regional Medical Center started offering the test late last week, Grenache said.
An antibody, or serology, test is different from the diagnostic tests that have been available in the state since March. Those gauge whether a person is currently infected with coronavirus.
It’s unclear what finding antibodies will mean, exactly, because scientists are unsure whether having them will stave off a future infection, Grenache said.
“When we think about COVID antibody testing, there’s actually very limited usefulness with that type of testing,” he said. “What is a doctor going to do with that test result? Doctors generally don’t order tests unless they are going to make a decision based upon it.
“If I was sick in January and I think, ‘did I have COVID? I want an antibody test.’ That’s not clinically actionable,” Grenache said. “You’re not going to make any decisions based upon that test result, because we don’t know yet if the antibodies we detect provide immunity.”
At Christus, about 30 people have been tested, and all have been negative, said Dr. James Marx, executive director of quality, patient safety and infection prevention at the hospital.
Last week, Dr. David Scrase, Cabinet secretary for the Health and Human Services Department, said antibody testing can be a useful public health tool.
Many who are exposed to the virus never show symptoms, he said. Antibody testing can give health officials insight into how far the virus has unknowingly spread in a community.
The governor’s New Mexico Medical Advisory Team, which includes Grenache, is recommending that the antibody tests be used as a complementary tool for patients who have tested negative for COVID-19 but are still suspected of having it, and patients who recovered from a serious respiratory condition in recent months but were never confirmed to have the disease.
The advisory team is also recommending that the tests be used to study community infection rates, possible immunity from the virus, and long-term outcomes for symptomatic and asymptomatic COVID patients.
Grenache said the tests could also be used to find recovered COVID patients who are willing to donate their plasma to others who are struggling with the disease.
Jodi McGinnis-Porter, a spokeswoman for the state Human Services Department, cautioned against buying antibody tests not authorized by the FDA and CDC. She said some such tests are being marketed.
“A wrong test result could, for example, indicate individuals have immunity against the virus when they don’t, potentially resulting in behavior that would endanger themselves, their families and every person that person comes into contact with,” she told the Journal in an email.
At Christus, the hospital is collecting blood samples and sending them to the Mayo Clinic to test for antibodies. At TriCore, Grenache said the testing is being done at its lab in Albuquerque using chemical reagents purchased from a company that TriCore has a long history of working with.
“Ultimately, if (doctors) order the test, we are obligated to perform it. It’s really mostly about communicating about how these tests should be used and how they should not be used,” Grenache said.
Marx said that Christus is allowing its physicians with patients who are not hospitalized to order the lab work. He said physicians are telling patients that testing positive for antibodies doesn’t ensure immunity.
It’s unclear whether many will seek out the testing, he said, because Santa Fe County has comparatively low rates of the coronavirus.
Grenache said TriCore officials are expecting the tests to be in high demand. The lab will have an initial capacity of 300 tests per day.
“I know that there will be high demand, but I’m very concerned that people aren’t going to use the tests in the right way,” he said. “Without knowing (if antibodies make people immune), all you are doing is satisfying a curiosity. And that’s not a good reason to use laboratory tests.”