COVID 19 PCR, SARS-CoV-2, Coronavirus
This is a qualitative PCR test for the detection of SARS-CoV-2 nucleic acid in bilateral anterior nasal swabs from asymptomatic patients. Nasal swab collections are intended for screening patients to increase testing for the detection of SARS-CoV-2 infections. Patients should be asymptomatic individuals without known or suspected exposure to SARS-CoV-2 for early identification in special settings.
It is recommended that symptomatic patients be tested with nasopharyngeal collection kits using test code COV19.
NOTE: This test is not available Urgent/STAT. Testing is performed on the ROUTINE high throughput pathway at the Marshfield campus. Allow up to 48 hrs for results including Pre-Procedure testing scheduled to allow 48 hours prior to procedure.
All test results are reported to the Wisconsin Electronic Disease Surveillance System (WEDSS). Confirmed and suspected COVID-19 disease is a Category 1 reportable condition in Wisconsin.
Marshfield Labs Wet Nasal Swab Collection Kit- Yellow Labeled, High throughput routine testing including Pre-Procedure testing scheduled to allow 48 hours prior to procedure:
Instructions and printable.pdf for the collection of bilateral anterior nasal specimens:
1 Insert the entire soft end of the swab into nostril no more than ¾ of an inch (1.5 cm) into the nostril.
2. Slowly rotate the swab, gently pressing against the inside of nostril at least 4 times for a total of 15 seconds. Get as much nasal discharge as possible on the soft end of the swab.
3. Gently remove the swab.
4. Using the same swab, repeat steps 4–6 in other nostril with the same end of the swab.
5. Place swab into the Azer buffered saline transport tube and carefully break off the swab shaft against the side of the tube at the score line. Discard the top portion of the swab shaft. Securely close the snap cap of tube.
Transport specimen at 2-8°C to Marshfield Labs as soon as possible. If specimen cannot be tested within 72 hours of collection, it should be frozen at -70°C or colder until tested. Testing is batched throughout the day.
Marshfield Labs COVID-19 Nucleic Acid Test assays are Emergency Use Authorization (EUA) assays performed on multiple platforms.
MCHS Laboratory Summary on SARS-COV-2 Assay Sensitivity and Specificity
The performance characteristics of the NASCOV assay such as sensitivity and specificity were determined using SARS-COV-2 PCR with nasopharyngeal specimens.
The current SARS-COV-2 PCR tests used at MCHS have been authorized for use by regulatory authorities including the FDA and CDC. These tests are highly specific (no false-positives) and are considered to be very sensitive, approaching 100%, during symptomatic disease when high titers of viral target are present, including directly before symptoms appear and following symptom resolution for several days. Appropriate collection technique is a critical variable for best test performance.
Assays performed at MCHS use validated gene targets and reagents, strict quality control, and qualified testing personnel. Results generated are comparable to those produced by public health and academic laboratories nationally. 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.
Positive – SARS-CoV-2 nucleic acid detected.
Negative – No SARS-CoV-2 nucleic acid detected.
Indeterminate - Result is indeterminate due to a PCR inhibitor present in the specimen. Consider repeat specimen if clinically indicated.
Consider submitting a repeat specimen if clinically indicated.