CHARLESTON, SC – Roper St. Francis Healthcare on Wednesday began offering antibody testing for COVID-19 ordered by physicians and asking that testing be limited to those who have shown symptoms of COVID-19.
Communities across the country are looking to antibody testing as another potential tool in deciding how and when they can resume normal operations. Antibody tests won’t indicate the presence of COVID-19, but they will measure whether your immune system has responded to the infection. False positive results are possible, even likely in the Lowcountry.
That’s why Dr. Rick McEvoy, who is the medical director for pathology, oncology and lab at Roper St. Francis Healthcare, is encouraging physicians to limit testing to those who have shown symptoms of COVID-19, such as the combination of shortness of breath and fever. He also emphasized that a positive result does not mean a patient is immune from COVID-19.
“We’ve done everything we can at Roper St. Francis Healthcare to bring on the best test available with the fastest turnaround time and the most up-to-date information for the patient,” McEvoy said. “The federal government (Food and Drug Administration) had made it exceptionally clear that the idea you can go get this test and not have to worry about COVID-19 anymore is just not the case.”
Although RSFH has a federally approved antibody test with high sensitivity, or the ability to detect whether the antibody is present, and high specificity, or the ability to exclude those who don’t have the antibody, it still can produce false positive results. The sensitivity of the test is 95 percent, which means five out of 100 patients taking the test might receive a false positive. If that test is taken by thousands of people who never have had COVID-19 symptoms, that could be hundreds of false positives, especially in a community such as the Lowcountry in which a small percentage of the population – less than 2 percent – has actually had COVID-19.
“We are hoping that with a doctor’s order that these patients show up and have some sort of symptoms, such that the prevalence for that patient would rise above the general community,” McEvoy said. “That way, if they get a positive, we’d be much more comfortable that they had a true positive rather than a false positive.”
The flip side is that if your test is negative, it’s 100 percent certain that you haven’t been exposed, he said. The limitations of the test only are for those testing positive.
“If your test is negative, you can feel sure that you have not been exposed,” he said. “This is an extremely good test, and if a patient had COVID-19 symptoms and tested positive, you know the patient has been exposed. The problem is some have been talking about testing everyone – even those without symptoms.”
It’s important to underscore that so little is known of COVID-19 that a positive result doesn’t change the way you should use personal protective equipment or follow social distancing restrictions.
The antibody test will be available in any Roper St. Francis Healthcare outpatient lab setting, and physicians will have results within 48 hours. Those who have experienced COVID-19 symptoms should wait a minimum of 14 days before testing. A doctor’s order is required.