Currently circulating mutant strain variants of influenza are detectable through Cepheid‘s respiratory tests, according to the molecular diagnostics company.

Two recently identified mutations in the matrix genes of the Human Influenza A virus have been reported to cause matrix gene target failure (MGTF) for several commercial diagnostic tests1, variants that Cepheid’s test, however, can detect.

The Influenza Variants

Variants of the (H1N1)pdm09 and A(H3N2) viruses containing matrix gene mutations are currently circulating around the world1. Recombination and other mutations of the viruses impact the performance of molecular diagnostic tests–which may lead to an increase in false negative test results. The greatest impact occurs in tests that detect only one genetic target of the influenza genome.2, 3

“In developing our portfolio of respiratory tests, we include multiple conserved gene targets to account for genetic drift within the influenza genome,” says David Persing, MD, PhD, EVP and chief scientific officer of Cepheid. “The resulting target redundancy mitigates the impact of mutational drift. Our three-gene target design for detection of influenza A reduces the risk of false-negative test results, even in the event of an MGTF.”

Cepheid’s respiratory tests all utilize a multi-target approach for the detection of influenza, providing target redundancy to mitigate the potential impact of genetic shift and drift on strain detection.

These tests include:

  • Xpert Xpress Flu/RSV
  • Xpert Xpress SARS-CoV-2/Flu/RSV^
  • Xpert Xpress CoV-2/Flu/RSV plus^

References:

  1. Jørgensen RL, et al. Emergence of circulating influenza A H3N2 viruses with genetic drift in the matrix gene: be alert of false-negative test results. 2022. APMIS. 130(10): 612–617.
  2. Overmeire Y et al. Severe sensitivity loss in an influenza A molecular assay due to antigenic drift variants during the 2014/15 influenza season. 2016. Diagnostic Microbiology and Infectious Disease. 85(1):42-46.
  3. Binnicker MJ, et al. Identification of an Influenza A H1N1/2009 Virus with Mutations in the Matrix Gene Causing a Negative Result by a Commercial Molecular Assay.  2013. J Clinical Microbiology. 51(6):2006-2007.