INTENDED USE

The Chikungunya NS1 Rapid Test is a lateral flow chromatographic immunoassay for the qualitative detection of Chikungunya virus antigen (Chikungunya Ag) in human serum, plasma or whole blood. It is intended to be used as a screening test and as an aid in the diagnosis of infection with Chikungunya viruses. Any reactive specimen with the Chikungunya Ag Rapid Test must be confirmed with alternative testing method(s) and clinical findings.

SUMMARY AND EXPLANATION THE TEST

Chikungunya is a rare viral infection transmitted by the bite of an infected Aedes aegypti mosquito. It is characterized by a rash, fever, and severe joint pain (arthralgias) that usually lasts for three to seven days. The name is derived from the Makonde word meaning “that which bends up” in reference to the stooped posture developed as a result of the arthritic symptoms of the disease. It occurs during the rainy season in tropical areas of the world, primarily in Africa, South-East Asia, southern India and Pakistan. The symptoms are most often clinically indistinguishable form those observed in dengue fever. Indeed, dual infection of dengue and chikungunya has been reported in India. Unlike dengue, hemorrhagic manifestations are relatively rare and most often the disease is a self limiting febrile illness. Therefore it is very important to clinically distinguish dengue from CHIK infection. CHIK is diagnosed based on serological analysis and viral isolation in mice or tissue culture. An IgM immunoassay is the most practical lab test method. The Chikungunya IgG/IgM Rapid Test utilizes recombinant antigens derived from its structure protein, it detects IgG/IgM anti-CHIK in patient serum or plasma within 20 minutes. The test can be performed by untrained or minimally skilled personnel, without cumbersome laboratory equipment.

PRINCIPLE

The Chikungunya NS1 Rapid Test is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing mouse anti-Chikungunya NS1 antigen conjugated with colloid gold (Chikungunya Ab conjugates), 2) a nitrocellulose membrane strip containing a test band (T band) and a control band (C band). The T band is pre-coated with rabbit anti-Chikungunya NS1 antigen, and the C band is pre-coated with goat anti-mouse IgG antibody. The antibodies to Chikungunya antigen recognize the antigens.
When an adequate volume of test specimen is dispensed into the sample well of the cassette, the specimen migrates by capillary action across the test cassette. Chikungunya NS1 Ag if present in the specimen will bind to the Chikungunya Ab conjugates. The immunocomplex is then captured on the membrane by the pre-coated rabbit anti-Chikungunya NS1 antibody, forming a burgundy colored T band, indicating Chikungunya Ag positive test result.

Absence of the T band suggests a negative result. The test contains an internal control (C band) which should exhibit a burgundy colored band of the immunocomplex of goat anti-mouse IgG/mouse IgG-gold conjugate regardless of the presence of colored T band. Otherwise, the test result is invalid and the specimen must be retested with another device.