Are we asking too much of testing? - btbirkett@gmail.com - Gmail

Are we asking too much of testing? - btbirkett@gmail.com - Gmail

Are we asking too much of testing?

Research this week raised new questions about tests that are widely used to diagnose Covid-19, including the Abbott Laboratories test used by the White House, suggesting that false negative results may be fairly common. The Abbott test, which is used for rapid diagnoses, could miss between one-third and half of positive cases, according to a New York University study that hasn’t been reviewed by other scientists. (Abbott disputes the findings.) A separate, peer-reviewed study from Johns Hopkins researchers looked more broadly at a widely used group of diagnostics for current infections, called polymerase chain reaction tests. It found that false negatives were common when the tests were performed early in infection and that patients are likely to get the most accurate results when tested just a few days into having symptoms. President Trump and an Abbott Laboratories ID Now Covid-19 test kit. Photographer: Michael Reynolds/EPA The findings, though early, are surprising, especially because Covid-19 diagnostic tests are considered particularly reliable. But doctors have worried about false-negative results with these tests for a while, with some even turning to alternative tools like lung CT scans when a result seems suspect. It’s important to remember that coronavirus tests aren’t a crystal ball or a panacea. They are a snapshot, a black-and-white picture that can show one moment in time. The results indicate when the virus is spreading so widely that it can be found deep inside the nose, or whether it has taken such a hold that there are signs in the blood that the immune system has been activated to fight it off. While a picture is taken at a specific time, with a before and after, the virus itself moves in ranges. Early in an infection, levels may be low, perhaps not even detectable. And some people don’t produce a strong enough immune response to leave evidence of the infection. That doesn’t even take into account fraudulent assays, or problems with the swabbing that kick-starts the testing process. An accurate test can’t do much with an inadequate patient sample. These are problems that have always existed with laboratory tests, but in the middle of a global pandemic the consequences could be vast and far-reaching, not just for a patient, but for the health of a community.—Michelle Cortez and Emma Court