The Truth About Antibody Tests

We’re asking public health officials and experts to answer your questions about the COVID-19 pandemic. Keep in mind that this information does not constitute professional medical advice. For questions regarding your own health, always consult a physician.
There’s been a recent surge in interest among our readers for information about available tests that will feasibly determine whether or not they've built up antibodies against the coronavirus. Why all the attention? Well, in the last week and a half, 90 different tests have come on the market and a USC study suggested somewhere between 220,000 and 440,000 Angelenos have already been infected with COVID-19.
But while these tests “hold promise for a variety of things,” says Dr. George Rutherford, a professor of epidemiology and biostatistics at the University of California, San Francisco, they’re “not a panacea by any stretch of the imagination.”
“For people like me, they're great for epidemiologic studies to understand where the virus has been, but they're not particularly good for a diagnosis, because it takes something like at least 11, 12 maybe as many as 18 days for them to turn positive after infection.”
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