Study: Test used by White House still misses many cases

The coronavirus test from Abbott Laboratories used at the White House to get rapid answers to whether someone is infected may miss as many as half of positive cases, according to a report from New York University.

The analysis, which has yet to be confirmed, found that Abbott’s ID NOW missed at least one-third of positive cases detected with a rival test and much as 48% when using the currently recommended dry nasal swabs, according to the report posted on BioRxiv, a server where researchers post early work before it has been reviewed by other scientists.

The results, if confirmed, indicate that the Abbott test may still suffer from very high false negative rates despite changes recommended by Abbott to avoid such a problem. In April, after other academic researchers raised concerns about high false-negative rates, Abbott recommended that clinicians avoid storing samples in socalled transport media, a liquid used to keep a sample, as that might dilute the test and lead to false negatives.

But when the NYU authors attempted to account for changes recommended by Abbott to avoid false negatives by using dry swabs, the performance was even worse. It missed the virus in 48% of the samples that were positive using Cepheid GeneXpert, a standard reference test sold by Danaher Corp. The NYU study hasn’t yet been reviewed by outside experts or published in a scientific journal.

Abbott didn’t immediately comment on the study.

False negatives have been a concern. Doctors have reported patients with obvious signs of the disease testing negative. While the scale of the problem hasn’t yet been determined, experts agree that it is prevalent.

False negatives not only hinder the diagnosis of disease in individual patients and an accurate understanding of the full scope of the outbreak, but they also risk patients who think they aren’t ill further spreading the virus.

Doctors at hospitals around the country have reported patients testing negative sometimes multiple times before eventually testing positive. Some doctors have instead at times turned to other methods of diagnosis, such as chest X-rays or CT scans.

The White House is frequently testing staff, governors, lawmakers, reporters and others who come in close contact with the president using ID Now. The testing machine, which is roughly the size of a toaster, is also more portable and doesn’t require deep nasal swabs, about which the president once said there is “nothing pleasant.”