To evaluate the efficacy and reliability of commonly available tests for the diagnosis of dengue fever in children in Karachi.

Background: Diagnosis of dengue fever in financially constrain t countries like Pakistan is usually made on immunochromatographic (ICT) based serological tests. Objectives: To compare the diagnostic accuracy of commercially available dengue rapid immunochromatographic tests (ICT) with dengue ELISA in acute dengue infection in children. Study type, settings and duration: This retrospective study was carried out at the Nat ional Institute of Child Health, Karachi in the Department of Pathology from October 2010 to January 2011. Patients and Methods: Hospitalized children who fulfilled the WHO and CDC definition of probable dengue fever i.e. fever of 2 to 7 days with two or more than two of the associated symptoms like headache , retro orbi tal pain, myalgia, arthralgia, rash, hemorrhagic manifestation, leucop enia, thrombocytopenia and supporting serology were included in the study after taking informed consent from their par ents / care givers. Malarial parasite positive case s were excluded from the study. Dengue ICT based IgG, IgM, IgA antibodies were done using rapid devices, dengue NS 1 was done on ICT rapid device and dengue IgM was done using enzyme linked immunosorbent assay (ELISA) by micro titer well plate. Data entered and analyzed on SPSS version 16. Results: Out of 80 suspected cases(being a retrospective stu dy it would be better that we give number of all su spected cases and then delete the numbers that did not have complete tests), 39 fulfilled the criteria of susp ected dengue fever patients. Ages of these children ranged from 6 mont hs to 13 years. There were 18 males and 21 females. Mean haemoglobin was 8.7g/dl and mean haematocrit was 26.3%. Elevated haematocrit was seen in 7.5% cases only. Mean WBC count was 6164/cmm, with leucopenia seen in 33.3% and leucocytosis in 5.12% cases. Thrombocytopenia was present in all cases except one. Positivity rate o f dengue IgG was 25.64%, IgM 15.4%, IgA 43.59%, rapid antigen by ICT method 20.5% and ELISA IgM (by micro titer well- plate) was 76.9%. Sensitivity / specificity of dengue IgG, IgM, IgA and rapid antigen by ICT were compared with ELISA IgM (gold standard) and these were 33.3/100%, 16.67/88.89%, 50.0/77.78%, 23.3/88.8% respectively. Conclusion: ELISA IgM antibody (by micro titer well-plate) test was most reliable as compared to ICT tests. Among the ICT tests, dengue IgA antibody was superior to other tests.