URINE PCR: A USEFUL DIAGNOSTIC TOOL DURING THE ACUTE PHASE OF LEPTOSPIROSIS?

Dr. Sreevalsan T. V.* and Dr. Rohitha S. Chandra

Leptospirosis is associated with high mortality if early appropriate treatment is not provided. Blood Polymerase chain reaction (PCR) is a highly sensitive test in the early phase of illness. This prospective study aimed to find out the usefulness of urine PCR in diagnosing leptospirosis in the early phase of illness. 50 adults admitted to the Intensive Care Unit (ICU) within 7 days of onset of symptoms with suspected leptospirosis were enrolled. Blood PCR, urine PCR and IgM were tested. 21 patients were tested positive by one or more of the above-mentioned tests. The diagnostic yield of urine PCR in comparison to blood PCR was studied. The statistical analysis of the test results obtained by blood PCR and urine PCR was done using McNemar’s Chi-square test. It was found that 21 patients were tested positive for Leptospirosis by blood PCR, Urine PCR, or IgM or a combination of more than one of the above tests. Blood PCR was positive in 76.2%, urine PCR in 66.7% and IgM in 52.4%. It was also observed that among IgM-negative cases blood PCR positivity was 90% (9/10) and urine PCR positivity was 80% (8/10) and there was no statistically significant difference between blood PCR and urine PCR (p value=0.625). This study showed that when blood PCR was taken as the gold standard test for leptospirosis, the sensitivity of urine PCR was 81.25% in the first week of illness. Since urine PCR doesn’t require phlebotomy and the point-of-care machines can be transported anywhere, it has a huge potential as a diagnostic tool during suspected community outbreaks of leptospirosis.