Comparison of NS - 1 Antigen Detection by RDT and ELISA and its Correlation with RT PCR for Early Diagnosis of Dengue and Detection of Concurrent Serotypes DENV - 1, 2, 3 in Ananthapuramu District


Adireddi Paradesi Naidu*, Chitralekha Saikumar, G Swarnalatha, Sardar Sulthana and Sailaja Meeniga


Early diagnosis of dengue is important for appropriate clinical management and vector control. Different serological tests based on the principle of immunochromatography and Enzyme - Linked Immune Sorbent Assays (ELISA) is commonly used for detection of antigen and antibodies of dengue virus. The performance of these tests depends on the sensitivity and specificity. Hence, the study was undertaken to compare nonstructural protein - 1 (NS1) antigen detection by rapid and ELISA correlation with Real Time - Polymerase Chain Reaction (RT - PCR) for diagnosis of dengue and to detect serotypes by RTPCR Serotyping (1 - 4) kit at Tertiary care hospital, Ananthapuramu.

Materials and Methods

In this study 100 clinical suspected cases of Dengue were enrolled. All the collected sera a sample were subjected for NS1 antigen detection test by rapid test, NS1 ELISA, and RT PCR and also serotypes DENV - 1, 2, 3, 4 are detected from serum sample by RTPCR test. The results of rapid and ELISA tests were compared with real Time


Out of total 100 samples, 29 samples tested positive by NS1 Rapid test, 30 samples tested positive by NS1 ELISA, and 32 samples tested positive by RTPCR. The sensitivity, specificity of rapid dengue NS1 antigen test were 87.50 % & 98.52 % respectively when compared to RTPCR whereas that of NS1 ELISA were 93.75 % and 100 % when compared to RTPCR. Out of 32 samples tested positive by RTPCR, 2 samples were positive for DENV - 1, 26 samples were positive for DENV - 2, and 4 samples were positive were DENV - 3


NS1 ELISA test takes several steps and more time. RDT's require very less time about 15 - 30 minutes single step procedure. Even though RTPCR, ELISA have superior performance than RDT, in countries with fewer infrastructures and in remote areas, RDT's are more useful for early diagnosis and management of dengue with less expertise within a short time.