This test is done to assess the quantitative detection of Dengue Virus NS1 antigen as an aid to the diagnosis of Acute Dengue infection. NS1 antigen is a nonstructural protein found in infected patients from 1st day of fever upto 5 days after the onset of fever.Dengue Hemorrhagic Fever and Dengue Shock Syndrome are caused by infection of RNA Flavivirus transmitted by a mosquito vector. To determine dengue infection. NS1 antigen is a structural protein which is secreted by all flaviviruses, and is detectable up to 5 days after onset of illness. The NS1 antigen will disappear once seroconversion has occurred in the host. In MolQ laboratory we do it with ELISA method as per norms.