Diagnostic dilemma of dengue fever: how much reliability are there in rapidity

Rapid diagnosis of dengue infection is essential to patient management and disease control. In a rural tertiary health setting and diagnostic laboratories, dengue suspect cases were assessed with a rapid (15 minutes) immunochromatographic test and compared to an IgM capture enzyme-linked immunosorbent assay (ELISA) (2-3 days) and the reliability of the rapid test was tested. The objectives were to evaluate dengue rapid test against dengue IgM capture ELISA and to assess the scopes of such rapid tests in peripheral setting. A rapid immunochromatographic card test was compared with an IgM capture ELISA (National Institute of Virology, Pune, India) as the reference gold standard. The sensitivity and specificity of the test was compared over a period of five years in a rural tertiary hospital among 158 dengue suspects. The rapid test showed good sensitivity in the diagnosis of both primary and secondary dengue infection. The rapid test as confirmed by IgM capture ELISA was found to have specificity of 98.4% and a sensitivity of 96.4%.The positive predictive value was 93.1% and negative predictive value of 99.2%.The positive likelihood ratio worked out to be 62.6,with negative likelihood ratio was 0.036,signifying large impact. The rapid tests may be useful aid in screening in case of clinical diagnosis of dengue infection,particularly valuable in peripheral health settings,where it can hasten the initiation of firstline of management; while the ELISA has a place in central testing laboratories, aiding in resource optimisation.