By Michael Erman

NEW YORK (Reuters) – Abbott Laboratories’ speedy coronavirus test, which can deliver results within minutes, could be missing a third to nearly half of positive cases, according to a study from New York University researchers published on Wednesday.

Abbott contested the results of the study, which has not been peer-reviewed, and said it was unclear if the samples were tested correctly. 

The study said the Abbott ID NOW COVID-19 test missed around 48% of samples detected positive by Cepheid’s Xpert Xpress test from dry nasal swabs and a third of those kept in a substance designed for viral transport. The researchers said the study raises concerns about the suitability of the test – which is used at the White House – as a diagnostic tool.

“These results are not consistent with other studies of the test,” Abbott spokeswoman Darcy Ross said in a statement.

She said the company has distributed more than 1.8 million ID NOW tests and the reported rate of false negatives to Abbott is at 0.02%.

Abbott’s test was approved in the United States in late March. It was the second test approved by the Food and Drug Administration that can be used directly in physicians’ offices and other community healthcare settings.

As of May 4, Abbott said it was producing 50,000 of the tests per day, and plans to ramp up to 2 million by June.

The NYU study is not the first to find issues with the test. A study conducted by the Cleveland Clinic in April showed the test detected the virus in around 85% of cases.

Abbott says the Cleveland Clinic study was performed using a method that dilutes the sample. Abbott said it updated its instructions and now tells its customers they should use a “direct swab method” to conduct the tests.

It says another study conducted by the city of Detroit found that the rapid test had 98% accuracy when compared to a molecular lab test.

(Reporting by Michael Erman; Editing by Leslie Adler)