SUMMARY AND EXPLANATION THE TEST
Dengue viruses, a family of four distinct serotypes of viruses (Den 1,2,3,4), are singlestrained, enveloped, positive-sense RNA viruses. The viruses are transmitted by mosquitoes of the daytime-bitting Stegemyia family, principally Aedes aegypti, and Aedes albopictus. Today, more than 2.5 billion people living in the areas of tropical Asia, Africa, Australia, and the Americas are at risk for dengue infection. An estimated 100 million cases of dengue fever and 250,000 cases of life-threatening dengue hemorrhagic fever occur annually on a worldwide basis.
Serological detection of IgM antibody is the most common method for the diagnosis of dengue virus infection. Lately, detection of antigens released during virus replication in the infected patient showed very promising result. It enables diagnosis from the first day after the onset of fever up to day 9, once the clinical phase of the disease is over, thus allows early treatment in placed promptly4-.The Dengue NS1 Rapid Test is developed to detect circulating dengue antigen in serum ,plasma or whole blood. The test can be performed by untrained or minimally skilled personnel, without laboratory equipment.
PRINCIPLE
The Dengue NS1 Rapid Test is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing mouse anti-dengue NS1 antigen conjugated with colloid gold (Dengue 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 mouse anti-dengue NS1 antigen, and the C band
is pre-coated with goat anti-mouse IgG antibody. The antibodies to dengue antigen recognize the antigens from all the four serotypes of the dengue virus.
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. Dengue NS1 Ag if present in the specimen will bind to the Dengue Ab conjugates. The immunocomplex is then captured on the membrane by the pre-coated mouse antiNS1 antibody, forming a burgundy colored T band, indicating a Dengue 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.
