Warde COVID-19 Testing: Guidelines for a Person Under Investigation
Matthew Sekedat, Ph.D
Scientific Director, Virology and Molecular Biology
Note: These guidelines have been updated on April 4, 2020 to reflect recent changes to the CDC guidelines and test availability.
The Center for Disease Control (CDC) is regularly updating their Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from Persons Under investigation (PUIs) for 2019 Novel Coronavirus (SARS-CoV-2) (1).
Providers now have options for testing a wider group of symptomatic patients through testing authorized by the Food and Drug Administration under Emergency Use Authorization (EUA) (2). In March, Warde Medical Laboratory verified the Abbott RealTime SARS-CoV-2 assay using Abbott’s m2000 qPCR system. In the first week of testing we provided over 5,000 results to patients and providers. Over 99% of these results were returned within 24 hours of arrival at the lab. The performance characteristics were verified using previously tested nasopharyngeal (NP) specimens and purified SARS-CoV-2 RNA. As with all nucleic acid tests, negative results may not indicate that the patient is not infected as viral load, collection protocol, and stability can all affect results.
In accordance with CDC recommendations, NP swabs are the preferred specimen for initial diagnosis. When collection of a NP is not possible, oropharyngeal, nasal mid-turbinate, and anterior nares swabs are acceptable alternatives, but may negatively affect assay sensitivity. We strongly encourage sending NP samples when available.
Specimen should be transported frozen in >1.5mL of viral transport medium when available. The FDA has approved Phosphate buffered saline (PBS), sterile saline, and liquid Amies media (e.g., ESwabs, Copan Diagnostics) as acceptable alternatives when viral transport media is unavailable. Our internal studies show that PBS and sterile saline do not interfere with the analytical performance of the COVID-19 assay. Liquid Amies buffer may decrease the analytical sensitivity of the assay and should be used only when other transport media are not available.
The Michigan Department of Health and Human Services (MDHHS) has up to date information for reporting a potential PUI, safety measure for health care providers, and patient treatment protocols for providers in Michigan (3).
In accordance with CDC recommendations that “(t)esting for other pathogens by the provider should be done as part of the initial evaluation but should not delay testing for COVID-19” (2), Warde accepts PUI specimens in IATA-approved containers for non-COVID respiratory panel PCR testing (4).
In keeping with CDC recommendations, Warde will not perform a Virus Culture from respiratory source samples until further notice.
Currently, SARS-CoV-2 PCR testing at Warde is prioritized by geographical location and requires a request to Laboratory Management before sending. Please contact the Warde Client Services line at (800) 760-9969 with additional questions regarding SARS-CoV-2/COVID-19 or RPCR testing.