After weeks of concerns about the accuracy of an Abbott (NYSE:ABT) rapid COVID-19 diagnostic test, the FDA last night issued a warning that the ID NOW test may return false-negative results.
Citing “early data,” the agency said it is “sharing early information … about potential inaccurate results in the spirit of transparency.”
A preliminary study released this week by researchers at New York University found that the test missed up to 48% of positive results. Researchers at the Cleveland Clinic reported in April that the ID NOW had a false-negative rate of 14.8%, according to a report by National Public Radio.
One issue is the treatment of specimens before they are placed in the ID NOW machine. Abbott advised customers on April 15 that placing specimens in liquid viral transport media before processing — standard procedure with tests that take longer to produce results — may dilute the samples. ID NOW was not designed for use with viral transport media, according to the company, which recommended using dry nasal swabs to collect samples.
The study conducted at NYU’s Langone Tisch Hospital compared the Abbot ID NOW COVID-19 and Cepheid Xpert Xpress SARS-CoV-2 molecular diagnostic tests using nasal swabs transported in a viral transport medium as well as dry nasal swabs for the Abbott assay. Abbott objected to the methodology of the NYU study, which has not been peer-reviewed or accepted for publication in a medical journal.
Abbott said in a statement that the NYU study results are not consistent with other studies — some with sensitivity performance in the 80th percentile and other studies with sensitivity at or above 90%. One study listed the test’s sensitivity at 94%, the company noted.
“While we understand no test is perfect, test outcomes depend on a number of factors including patient selection, specimen type, collection, handling, storage, transport and conformity to the way the test was designed to be run. ID NOW is intended to be used near the patient with a direct swab test method,” the company said. “It is our responsibility to provide healthcare professionals and the public with accurate information.”
Abbott said it is working to provide better guidance to healthcare providers that negative results should be considered in the context of a patient’s recent exposures, history and the presence of clinical signs and symptoms consistent with COVID-19. If negative results are inconsistent with clinical signs and symptoms, the patient should be tested again using another test, the company advised.
Abbott also said it is reinforcing proper sample collection and handling instructions and continuing to improve the ID NOW test “as the world learns more about this virus. We’re working to incorporate those learnings into the test as we do with all of our diagnostics tests,” the company said.
The FDA granted the ID NOW test an emergency use authorization (EUA) on March 27. Last night, the agency said it is reviewing 15 adverse event reports about the Abbott ID NOW device that suggest some users are receiving inaccurate negative results.
Specifically, the FDA said it is investigating whether the false-negative results could be due to the types of swabs used or the type of viral transport media.
“While there is important information to gather from these studies, it should be noted these studies have limitations, including small sample size, potential design biases, or tests that may not have been executed according to the manufacturer’s instructions for use, an important part of scientific research,” the agency said in a news release. “This is why external scientific studies are one part of the FDA’s overall evaluation of a diagnostic performance.”
“We are still evaluating the information about inaccurate results and are in direct communications with Abbott about this important issue,” added said Dr. Tim Stenzel, director of the FDA’s Office of In Vitro Diagnostics and Radiological Health. “We will continue to study the data available and are working with the company to create additional mechanisms for studying the test. This test can still be used and can correctly identify many positive cases in minutes. Negative results may need to be confirmed with a high-sensitivity authorized molecular test.”
Abbott has agreed to conduct post-market studies for the ID NOW device that each will include at least 150 COVID-19-positive patients in a variety of clinical settings. The FDA said it will continue to review interim data and will keep working with Abbott to further evaluate these accuracy issues and will publicly communicate any updates.
ABT shares were down 2% to $89.94 in pre-market trading.