Cirrus COVID-19 Antigen Test is intended to be used for the qualitative detection of SARS-CoV-2 nucleocapsid antigen in nasopharyngeal and oropharyngeal swab specimens from patients suspected of COVID-19.

The antigen can generally be detected in swab specimens taken during the acute phase of the infection. Positive results indicate that nucleocapsid antigen of SARS-CoV-2 was detected, however, it is necessary to check clinical correlation with the patient’s history and other diagnostic findings to determine the infection status. Positive results do not rule out bacterial infections and or co-infection with other viruses. The antigen detected may not be the definite cause of the disease.

Negative results do not rule out SARS-CoV-2 infection and a negative result should not be used as the sole basis for treatment, patient management, and infection control measures. In case of a negative result, a patient's recent exposures, history, and clinical findings consistent with COVID-19 should be taken into account and the result should be confirmed with a molecular test (for example RT-PCR).

The test employs a monoclonal antibody pair raised against the nucleocapsid antigen of SARS-CoV-2. The capture antibody is immobilized on the nitrocellulose membrane and the detection antibody was coupled to colored microparticles and stabilized on a conjugate pad. The swab sample is treated with the extraction solution and then the extracted sample is applied to the sample pad. As the sample migrates forward, if the SARS-CoV-2 nucleocapsid antigen is present, the antigen interacts with the detector antibody and then the complex is captured on the test line. A colored line (T) is visible indicating a positive result. A control line (C) is used for procedural control and it should always appear if the test procedure is performed properly. Cirrus COVID-19 Antigen Test is an in vitro diagnostic medical device (IVD) intended for professional use. The test should be used by trained clinical laboratory personnel.