Evaluation of Rapid Immunochromatographic Tests in Comparison to ELISA for Detection of NS1, IgM and IgG Antibodies for Early Detection of Dengue Infection in Pediatric Patients

ABSTRACT

Dengue fever is one of the most common arthropod-borne viral disease seen in humans. It is one of the major public health problems in developing countries including India. The signs and symptoms of dengue fever may range from moderate fever to thrombocytopenia, hemorrhagic manifestation and shock. Severe untreated cases may even prove to be fatal. The diagnosis of dengue fever may be made on the basis of detection NS1 antigen or IgM and IgG antibodies. This study was aimed at analyzing the sensitivity and specificity of RICT kit with ELISA for NS1 antigen and IgM, IgG detection so as to explore its suitability for regular use in any modest resource constrain laboratory or primary health center as a bedside test. Methods: This was a prospective cohort study conducted from August 2018 to Jan 2019 in a tertiary care private and teaching hospital. Informed written consent was taken from parents or caretakers of patients. The institutional ethical committee approved the study. Samples were collected during the acute phase of illness i.e. 1-5 days of fever. The samples were grouped into 2 categories according to the days of fever - 1-5days and 5-15 days. The NS1 Antigen, IgG and IgM antibodies tests were done by ELISA and ICT in all the cases. EDTA blood samples were collected & the platelet count was done. SSPE 21.0 software was used for statistical purpose. Results: A total of 200 blood samples were studied. Out of the 200 studied sample 132 (66%) belonged to male patients and remaining 68 (34%) belonged to female patients. The M F ratio was found to be 10.51. Most common age group of the patients was between 4-10 years (66%) followed by 15-18 (14.5%) and 11-15 years (10.5%). The least common age group was found to be less than 4 years of age (9%). 102 (51%) patients were having platelet count of less than 1 lac/mm3. The analysis of blood samples for NS1 antigen positivity showed that out of 200 sample NS1 was positive in 51 (25.5%) patients by ELISA and 49 (24.5%) patients by ICT. IgG/IgM ELISA was positive in 81 (40.5%) samples whereas IgG/IgM ICT was positive in 79 (39.50%) samples. Presence of either NS1 antigen or IgG/IgM antibodies was positive in 122 (61%) by ELISA and 119 (59.50%) by ICT. The comparison of NS1 ELISA and NS1 ICT showed that the results were comparable for both the tests with no statistically significant difference (P>0.05). Similarly, there was no statistically significant difference in IgG/IgM ELISA and IgG/IgM ICT and a combination of NS1 and IgG/IgM by ELISA and ICT (P>0.05). Conclusion: Performance of rapid diagnostic tests to detect the presence of Dengue NS1 antigen & IgM & IgG antibodies to dengue virus in comparison to ELISA in present specimen was found to be satisfactory. Even though RDT is treated as screening test places where other advanced diagnostics are not available RDT can be used for the diagnosis of Dengue virus infection.