Quidel disclosed Friday what it calls a first-of-its-kind antigen kit designed to test for influenza A, influenza B and SARS-CoV-2 from a single sample received emergency use authorization from FDA.
As the symptoms of flu and COVID-19 can be similar but treatments are different, tools are needed to differentiate the infections. Cepheid and Roche manufacture molecular multi-virus tests and Quest Diagnostics and LabCorp offer the combination options, but Quidel says its is the first in the form of an antigen kit.
- While major manufacturers BD and Abbott have joined the COVID-19 antigen test market since Quidel received the first such EUA from FDA in May, the latest EUA again sets Quidel apart.
Quidel's so-called "ABC" test (for flus A and B and the coronavirus) allows for an increase in production of flu tests as flu season begins without affecting the aggressive ramp-up of COVID-19 antigen tests, the company said. That's because three tests are performed simultaneously on one cartridge from a single swab sample.
Quidel said it became the latest company to receive an EUA for a multi-virus antigen test late last week. The test is designed to detect antigens from SARS-CoV-2, influenza A and influenza B in direct nasopharyngeal and nasal swab samples within 15 minutes. The point-of-care test consists of a cartridge that runs on Quidel’s Sofia 2 Fluorescent Immunoassay Analyzer.
FDA had not immediately posted documents outlining Quidel's EUA, but the company shared some data in its statement Friday, revealing the test achieved a positive percent agreement (PPA) of 95.2% versus PCR in the detection of SARS-CoV-2. The test achieved a negative percent agreement (NPA) of 100% in the detection of SARS-CoV-2.
Quidel assessed the ability of the test to detect influenza A and B by comparing its data to results from culture studies. Across the two types of influenza, the test achieved sensitivity of close to 90% and specificity of around 95%.
Cepheid secured EUA for its point-of-care PCR test for SARS-CoV-2, influenza A and B, and respiratory syncytial virus (RSV) on the strength of a study that linked the product to a PPA of at least 97.9% and a NPA of at least 99% among each of the four viruses. The PPA and NPA in studies of Roche’s nucleic acid test for influenza and SARS-CoV-2 were upward of at least 95.2% and 96%, respectively. Differences between study design and execution could affect the data, potentially making comparisons unreliable.
Studies of other antigen tests suggest the approach can miss cases detected by PCR but the speed of the diagnostic method and demand for COVID-19 testing has led to strong demand. Quidel has been scaling output throughout the year, leading it to predict a more than 400% jump in fourth quarter sales. The new multi-virus test is manufactured on the same lines as its SARS-CoV-2 kit.