Medical device company Abbott Laboratories has warned that its rapid coronavirus test can produce false negatives if the specimens tested are first stored in what are called viral transport media, which are special solutions used to move or store specimens.
Abbott instructed health care providers last week not to use such solutions for patient samples tested on the company’s rapid ID NOW device. False negative results suggest patients are not infected when in fact they are.
The guidance came more than two weeks after the Food and Drug Administration issued emergency authorization for the test and after President Trump touted the rapid Abbott system at a Rose Garden news conference.
Clinical pathologists and lab scientists at the Cleveland Clinic found that the ID NOW test only detected coronavirus in 84.4% of specimens known to contain the virus, which was a lower rate than four other tests the researchers assessed, a spokesperson for the Ohio-based medical center said. NPR first reported that assessment Tuesday.
The Cleveland Clinic spokesperson told CNN that a dilution effect can occur whenever a sample swab is placed into viral transport media, but she added that in the assessment, the tests were performed from the same viral transport media, so it was a true head-to-head comparison.
An issue of volume: Because Abbot’s ID NOW testing machine only processes one test at a time, labs might have used the transport media to store the test samples until they can be processed.
The company now advises its customers to place swabs containing patient samples directly in the ID NOW system for testing.
“When the direct swab method is used, the test is performing as expected and we are confident in its performance,” the Abbott spokesperson said, adding that when the company learned about the issue it immediately notified its customers and communicated with the FDA.