The Cepheid Xpert® Xpress SARS-CoV-2 RNA assay system is a qualitative real-time RT-PCR system that enables the direct amplification of Coronavirus SARS-CoV-2 RNA from nasopharyngeal swabs (preferred) or nasal swabs (when nasopharyngeal swabbing is not possible) in patients suspected of COVID-19 by their health care provider.
This SARS-CoV-2 assay is indicated for extremely time-sensitive testing [e.g., transplant recipients, Electroconvulsive Therapy (ECT), Interventional Radiology (IR) and cardiovascular patients in UH-PACU, CVC-CPU, and CVC-PACU].
Not detected by Cepheid
Positive results are indicative of the presence of SARS-CoV-2 RNA; clinical correlation with patient history and other diagnostic information is necessary to determine patient infection status. Positive results do not rule out bacterial infection or co-infection with other viruses.
Negative results do not preclude SARS-CoV-2 infection and should not be used as the sole basis for patient management decisions. Negative results must be combined with clinical observations, patient history, and epidemiological information. False-negative results may occur if the viruses are present at a level that is below the analytical sensitivity of the assay or if the virus has genomic mutations, insertions, deletions, or rearrangements or if performed very early in the course of illness.
The possibility of a false negative result should especially be considered if the patient’s recent exposures or clinical presentation suggest that SARS-CoV-2 infection is possible and diagnostic tests for other causes of illness (e.g., other respiratory illness) are negative.
Invalid results indicate the inability to conclusively determine presence or absence of SARS-CoV2 RNA in the patient sample. This result may be due to 1) Internal Control (IC) failure, or 2) failure to detect sufficient specimen volume.
The test will be performed immediately upon receipt in UH-Microbiology, with results reported within 2 hours of receipt, contingent upon testing capacity.
This test is currently available only to Michigan Medicine clinicians with the following approved usage: Transplant Patients, Electroconvulsive Therapy (ECT), Interventional Radiology (IR) and cardiovascular patients in UH-PACU, CVC-CPU, and CVC-PACU.
Additional information from the CDC can be found at https://www.cdc.gov/coronavirus/2019-ncov/index.html
The United States (U.S.) FDA has made this test available under an emergency access mechanism called an Emergency Use Authorization (EUA). The EUA is supported by the Secretary of Health and Human Service’s (HHS’s) declaration that circumstances exist to justify the emergency use of in vitro diagnostics (IVDs) for the detection and/or diagnosis of the virus that causes COVID-19. The EUA for this test is in effect for the duration of the COVID-19 declaration justifying emergency use of IVDs, unless terminated or revoked (after which the test may no longer be used).