Friday, July 5, 2013

Diagnostic Tests For Dengue Fever







Dengue is the most prevalent mosquito-borne viral illness, with at least; 100 million dengue virus infections occuring each year worldwide. Patients with dengue virus infections can have a wide range of symptoms, from a mild fever to a life-threatening shock syndrome.


History


The diagnosis of acute dengue virus infection is mainly based on signs and symptoms. Most of the developing countries do not have laboratory confirmation available. In developed countries, such tests are usually available only in specialized centers.


Identification


Confirmation of acute dengue virus infection is most frequently accomplished using serology. Tests for detection of viral antigen are available outside the U.S. and help detection of dengue virus infection in the early stages .


Identification


IgM immunoassay (MAC-ELISA) is the test of choice for rapid confirmation of the diagnosis. The test should be repeated in at least 10 to 14 days if the initial test was negative. The initial and later samples should be analyzed together by a hemagglutination inhibition (HI) or enzyme immunoassays to provide definitive serologic testing for acute dengue infection.


Identification


In Serologic testing, hemagglutination inhibition (HI) assay and IgG or IgM enzyme immunoassays are most frequently used. A fourfold or greater rise in HI antibody titer between initial and later samples defines acute infection.


Identification


Complement fixation and neutralizing antibody assays are technically more demanding and are used in specialized laboratories only.


Identification


Immunoassays: Detection of dengue virus-specific IgG antibodies have sensitivity and specificity of 99 percent and 96 percent, respectively, compared to the HI assay .


Identification








Isolation of dengue virus or detection of dengue viral RNA or protein in serum or tissue specimen provides confirmation of infection. But these assays have limited application applications due to their complex techniques. They are generally performed for epidemiologic purposes or for the clinical research.

Tags: dengue virus, acute dengue, dengue virus infection, virus infection, acute dengue virus