The Lab Medicine Department of Apollo Hospitals Dhaka has introduced a new test for the diagnosis of dengue infection. The test, named DENGUE NS1 ANTIGEN, is a qualitative or comparative determination of dengue virus NS1 antigen in human serum (blood) for the diagnosis of early acute dengue infection. An antigen is a toxin or foreign substance that induces an immune response in the body, esp. the production of antibodies (immunoglobulins).
Dengue is considered to be the most important arthropod-borne viral disease due to the human morbidity and mortality it causes. In Bangladesh, dengue infection is conventionally detected by measuring the presence of Immunoglobulin M (IgM) and Immunoglobulin G (IgG) in the serum of suspected dengue patients for both primary and secondary cases of infections. IgM and IgG are two of the five major classes of immunoglobulins, the main antibody defense of the body. However, IgM does not become detectable until 5 to 10 days after the onset of illness in cases of primary dengue infections and until 4 to 5 days after onset of illness in secondary infections. On the other hand, IgG appears on the 7th to 14th day for primary infections and persist for life; secondary infections show that IgG rises within 1-2 days after the onset of symptoms. This delay in diagnosis of dengue infection may hinder the speedy and proper treatment of suspected patients and cause unnecessary anxiety for the patient and family.
NS1 is a highly-conserved glycoprotein that is present at high concentrations in the serum of dengue-infected patients during the early clinical phase of the disease. NS1 antigen is found from the first day and up to 9 days after onset of fever in primary or secondary dengue infected patients. Thus, NS1 antigen can be detected immediately after the start of the fever, making early diagnosis and immediate treatment of dengue infection a possibility.