Summaiya Mullan
Govt. Medical college, India
Title: Determination of cut-off titre of ELISA test used in diagnosis of Leptospirosis in south Gujarat
Biography
Biography: Summaiya Mullan
Abstract
Re-establishing the cut-off titre for IgM ELISA using ROC (Receiver Operating Characteristic) curve in South Gujarat region because cut off titre for these serological tests needs to be re-confirmed at timely intervals keeping in mind the endemicity of Leptospirosis in the region. For determining the ROC curve and the cut off titre, 30 healthy population from each geographic region like districts Tapi, Navsari and valsad, 30 patients with diseases other than Leptospirosis as well as 30 known Leptospirosis cases was taken from South Gujarat region and tested for Panbio ELISA for leptospirosis. All the data obtained by testing was entered into SPSS (Statistical Package for Social Sciences) software for ROC analysis. Analysis showed best cutoff value for valsad and navsari 14.5 panbiounits and for tapi 16.5 panbiounits as being higher than kit base cutoff value of 11 panbiounits. Using the cutoff value recommended by the manufacturer (11 Panbio units), the sensitivity on paired sera is high (90.8%) and may be used to rule in patients with suspected leptospirosis. However, the poor specificity of the test (55.1%) suggests that using this test in the clinical setting could lead to over diagnosis of leptospirosis and a high frequency of false positivity. Using the high cutoff value generated by ROC curve analysis (15 Panbio units), the overall accuracy of the test was improved. We recommend as WHO to use such an assay for the diagnosis of leptospirosis if financial resources permit requires area -specific evaluation to determine its clinical use before implementation.