Lab Test

SARS-CoV-2/Influenza A and B Antigens

Only Available to EC Providers
Coronavirus, 2019-nCoV, COVID, SARS, Flu A, Flu B

Test Codes


Specimen Collection Criteria

Collect: Swab (provided in kit): Dry Nasal Swab

Physician Office/Draw Specimen Preparation

Not applicable.

Preparation for Courier Transport

Not applicable.

Rejection Criteria

Swabs in viral transport media, saline (PBS), or liquid Amies.

In-Lab Processing

Point of Care (POC) Processing
Maintain all specimens at room temperature (15-30°C) or refrigerated (2-8°C) prior to testing.


Point of Care Storage

Specimen Stability for Testing:

Room Temperature (15-30°C/59-86°F): 48 hours
Refrigerated (2-8°C or 36-46°F): 48 hours

Specimen Storage in Department Prior to Disposal:

Specimens are discarded immediately after testing.


Point of Care Testing in Emergency Centers

Canton Emergency Centers
Dearborn Emergency Centers
Farmington Hills Emergency Centers
Grosse Pointe Emergency Centers
Royal Oak Emergency Centers
Taylor Emergency Centers
Trenton Emergency Centers
Troy Emergency Centers
Wayne Emergency Centers


Sunday – Saturday, 24 hours a day.
Results available at the point of care within 15 minutes of loading on the analyzer.

Reference Range

Not Detected: No SARS-CoV-2, influenza A, or influenza B detected.

Test Methodology

The Sofia Flu + SARS Antigen Fluorescent Immunoassay (FIA) assay employs immunofluorescence technology in a sandwich design that is used with the Sofia 2 instrument at the point of care. This test has been issued Emergency Use Authorization (EUA) by the US Food and Drug Administration (FDA). This test is not FDA cleared or approved.


This assay determines the presence of SARS-CoV-2, influenza A, and influenza B antigens in a nasal specimen.

This assay should only be performed on symptomatic patients.

A negative SARS-CoV-2 antigen result should be treated as presumptive and must be confirmed with a molecular polymerase chain reaction (PCR) assay if the patient is being admitted to the hospital.

Positive influenza A and or influenza B antigen tests in symptomatic patients should be considered presumptive and should be confirmed with a molecular PCR assay. During peak influenza season (late December through March) positive flu A or flu B antigen tests do NOT need to be confirmed with a molecular PCR assay.

Clinical Utility

Symptoms of a respiratory virus infections may include fever, cough, sore throat, and malaise, which is also seen in patients with COVID-19. Due to the differences in patient treatment and management, it is necessary to differentiate COVID-19 from other common respiratory infections. This assay aids in the detection and differentiation of SARS-CoV-2 (CoVID-19), influenza A, and influenza B. This assay detects the pathogen's antigen and does not rely upon seroconversion.

Clinical Disease

Symptoms of SARS-CoV-2 (CoVID-19) infection are similar to those of other respiratory viruses that occur seasonally in the fall/winter and include:

  •  Fever
  •  Sore throat
  •  Dry cough
  •  Chills
  •  Fatigue
  •  Pneumonia
  •  Shortness of breath


Respiratory viruses typically follow a seasonal pattern with an increase of infections beginning in the fall and winter. Most cases of influenza occur in the winter and early spring (January through April) with peak incidence in January and February. SARS-CoV-2 is the cause of a worldwide pandemic that has resulted in tens of millions of infections and hundreds of thousands of deaths since its emergence in December 2019. As an emerging pathogen, the seasonal pattern of SARS-CoV-2 is currently unknown.

Incubation Period

SARS-CoV-2: According to estimates from the World Health Organization (WHO), the incubation period for SARS-CoV-2 ranges from 2 – 14 days with a median incubation period of 5 days. Patients are infectious 1-2 days before the onset of symptoms and up to 10 days thereafter. Immunocompromised and critically ill patients may shed infectious virus for longer periods of time.

Influenza: The incubation period is 18-70 hours. Patients are infectious one day before the onset of symptoms and for 3-4 days thereafter. Infants and immunocompromised patients may shed infectious virus for longer periods of time.


These viruses are very contagious and are transmitted through inhalation of virus-laden aerosols or by autoinoculation after handling fomites contaminated with nasal or throat secretions.

CPT Codes

LOINC:  94306-8, 95942-9, 95209-3


Last Updated


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