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The CDC Offers a Multi-Virus Testing Option with the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay

October 23, 2020

With flu season typically starting in October and peaking between December and February, the Centers for Disease Control and Prevention (CDC) have developed two tests that identify the COVID-19 virus (SARS-CoV-2). The latest of these two tests, called the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay, tests for influenza A and B viruses as well as SARS-CoV-2.

Along with the new test, the AMA has published new CPT additions and editorial revisions regarding response to the COVID-19 pandemic. The codes are approved for immediate use and can be found, along with long descriptions, in a recently published AMA press release. Short and medium descriptors for the new and revised codes can be found on the AMA website. Information about distinguishing the two seasonal infections from the infections caused by SARS-CoV-2 is the cpt Assistant Special Edition October update.

Testing for all three viruses at the same time will provide public health officials with information they need to help reduce the spread of these viruses in the community while conserving resources that are in short supply

Center for Disease Control and Prevention (CDC)

“Two of the newly approved codes report nucleic acid assays that allow a single test to simultaneously detect the novel coronavirus and a combination of common viral infectious agents, including influenza A/B and respiratory syncytial virus,” said AMA President Susan R. Bailey, M.D. “Concurrent detection promises to conserve important testing resources, allowing for ongoing surveillance of influenza while testing for the novel coronavirus.”

About the Multiplex Assay

While the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay is critical because of its ability to assess three viruses in a single test and that more testing will help in the fight against these viruses, other benefits include:

  • Public health officials obtain the information needed to help control the spread of the flu and COVID-19.
  • While testing Cor COVID-19, health professionals are also surveilling for ongoing flu.
  • Three viruses in one test help conserve testing supplies that are in short supply.

Ordering the Assay

According to the CDC, the International Reagent Resource distributes the assay and supplies to registered state and local public health laboratories.

“During the COVID-19 pandemic, state public health laboratories can authorize county or city laboratories in their state to perform testing,” wrote the CDC. “These laboratories must be certified under the Clinical Laboratory Improvement Amendment (CLIA) to perform high-complexity tests, have appropriate laboratory equipment and training, and demonstrate testing proficiency under their state laboratory’s stewardship to maintain their status as an IRR-registered laboratory. The IRR does not supply clinicians, hospitals, or healthcare professionals with testing kits directly. A list of commercially available primers and probes for use with this test is not available at this time. However, the CDC has shared the primers and probes sequences, so other laboratories and companies may manufacture their own reagents.”

Assay Materials

According to the CDC, the CDC Influenza SARS-CoV-2 (Flu SC2) Multiplex Assay, which is a quadruplex assay, includes:

1. One primer mix and one probe mix. Primers and probes target:

  • Virus nucleocapsid (N) gene for specific detection of SARS-CoV-2
  • Matrix (M1) gene for specific detection of influenza A virus
  • Nonstructural 2 (NS2) gene for specific detection of influenza B virus
  • RNase P gene (RP) for specific detection of human nucleic acid that serves as an internal control

2. A positive control FluSC2PC that confirms all four targets in the assay are working correctly

Read the article, “CDC’s Diagnostic Multiplex Assay for Flu and COVID-19 at Public Health Laboratories and Supplies,” for more information. You’ll also find resources and fact sheets regarding the assay and testing for COVID-19 and flu, including:

  • FDA-authorized Instructions for Use – Information about the test, its intended use, the test procedure, and test performance characteristics
  • FDA Letter of Authorization – Defines the authorized use and conditions of authorization that apply to CDC and other testing labs using the test

Stay informed on COVID-19 testing, testing supply needs, and payor billing requirements by visiting our COVID-19 Laboratory Resource Center.

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