COVID 19, SARS-CoV-2, Coronavirus, Influenza
This is a qualitative molecular test for the detection of nucleic acid of coronavirus 2 (SARS-CoV-2) and Influenza virus types A and B in nasopharyngeal swabs from patients presenting with respiratory symptoms. Combination testing is most useful during periods when these viruses are in known circulation in the community. Patients may have mild to severe respiratory illness with symptoms of sore throat, cough, fever, headache, congestion or runny nose, shortness of breath and complications including pneumonia.
Notes: This test is not available STAT. This test does not detect respiratory syncytial virus (RSV) or differentiate between seasonal subtypes of influenza A.
Refer to the MCHS COVID-19 Test Kit Selection for specimen collection guidance.
All SARS-CoV-2 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.
Collect a nasopharyngeal specimen using the NP swab. Place swab into the appropriate transport medium 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 can not be tested within 72 hours of collection, it should be frozen at -70°C or colder until tested. Testing is batched throughout the day.
Nucleic Acid Test (NAT); Real-Time RT-PCR
Marshfield Labs COVID-19/Influenza 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 current COVID-19/Influenza 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/Influenza 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 – Result indicates that the specific virus nucleic acid is detected and suggests infection with the virus.
Negative –Result indicates that the specific virus is not detected.
Indeterminate - Result is indeterminate due to a PCR inhibitor present in the specimen. Consider repeat specimen if clinically indicated.