The use of antibody-based Immunoglobulin M (IgM) ELISA (Enzyme-Linked Immunosorbent Assay) test has been stressed for generation of accurate results of the viral disease.
Officials said that many hospitals and laboratories were using rapid diagnostic test (RDT) which can generate inaccurate results, that is, false positive or false negative results.
“Hospitals and laboratories have been instructed to use IgM ELISA test to confirm dengue. Use of RDT test kit can generate false results at times,” said P.G. Bhanumathi, Deputy Director of Health Services, Coimbatore.
According to senior doctors, NS1 (Nonstructural Protein 1) antigen-based rapid testing kit is normally used to detect dengue in the early stage.
Hence, chances are very high for RDT methods to generate a false negative result if samples are tested after five days.
When samples are tested using RDT method, there are also chances for the dengue virus to have cross reaction with other flavi viruses, malaria parasite, and leptospiras which may alter the actual result.
The dengue virus may also have cross reaction with immune disorders such as rheumatoid and lupus.
Health Department suspect that several medium range private hospitals and laboratories still use RDT method for dengue diagnosis.
Dr. Bhanumathi said that District Headquarter Hospital at Pollachi and Coimbatore Medical College Hospital were equipped to perform IgM ELISA test for dengue detection. In the private sector, several multi-speciality hospitals and laboratories had the same facility.
She said that hospitals and laboratories with IgM ELISA facility could perform the examination for which they need not require any approval from the government as in the case of testing A (H1N1) influenza virus.