A Comparative Study of Serum, Urine and Saliva Using rk39 Strip for the Diagnosis of Visceral Leishmaniasis.

Background: Immunochromatographic based rk39 antibody detection test became popular for the diagnosis of visceral leishmaiasis (VL) because of high sensitivity, rapidity, easy to interpret, and cost effectiveness. However, false positive result after complete cure of the patients is the major limitation with this test. The aim of the study to access the usefulness of non-invasive samples i.e. urine and saliva by rk39 test for the diagnosis of visceral leishmaniasis in comparison to serum.

Methods: Seventy two clinically suspected VL patients were enrolled in the study among which 61 cases were confirmed as VL and 11 cases were included in the control group. Serum, urine, and saliva samples of all the cases were tested for rk39 dip stick test.

Results: Urine and saliva both were equally sensitive as serum for the diagnosis kala-azar. In the control group, rk39 antibody test was negative in 10 cases out 11 (91%) with saliva in comparison to 4 cases with serum (36%), thereby found to be more specific.

Conclusion: Saliva sample found to be highly reliable for the diagnosis of VL cases by rk39 test. The test with saliva sample showed less false positive result in comparison to serum sample, thereby can be used an adjunct with serum sample for the diagnosis of kala-azar in endemic areas.