Rapid Diagnostic Tests for Visceral Leishmaniasis Reviewed

The effectiveness of rapid diagnostic tests (RDTs) in diagnosing patients with visceral leishmaniasis (VL) has been reviewed by an independent expert group.

VL is caused by a parasite and results in fever, a large spleen and other health problems and diagnosis is extremely important as without treatment it can be fatal and proper treatment can result in a cure.


Scientists from the Cochrane Infectious Disease Group, coordinated through the editorial base in Liverpool School of Tropical Medicine (UK) found 24 studies, which contained information about five different RDTs, with a total of 4,271 participants. They describe how accurate these rapid diagnostic tests are for diagnosing VL in people who, according to their physicians, could have the disease. Only studies in which the investigators had used established methods to distinguish the people with VL from those who did not have the disease were used in the review.

One RDT, the rK39 immunochromatographic test (ICT) gave correct, positive results in 92% of the people with VL and it gave correct, negative results in 92% of the people who did not have the disease. The test worked better in India and Nepal than in East Africa. In India and Nepal, it gave correct, positive results in 97% of the people with the disease. In East Africa, it gave correct, positive results in only 85% of the people with the disease.

In 11 of the studies, the InBios rK39 ICT test (Seattle WA, USA) was used; four studies assessed the DiaMed rK39 ICT test (Cressier, Switzerland) and three evaluated other tests. There were no significant differences in diagnostic accuracy between commercial brands. A second RDT, the latex agglutination test gave correct, positive results in 64% of the people with the disease and it gave correct, negative results in 93% of the people without the disease.

Marleen Boelaert, PhD, from Institute of Tropical Medicine (Antwerp, Belgium) and the senior author of the report, said, “The best chance of a cure for VL lies in a correct diagnosis, so utilizing accurate RDTs is of paramount importance. Our review indicates that the rK39 ICT shows higher sensitivity and specificity for the diagnosis of VL in patients with febrile splenomegaly and no previous history of the disease than the latex agglutination test, but the sensitivity is notably lower in East Africa than in the Indian subcontinent. The size of the studies involving the other RDTs lack accuracy, validation, or both.” The report was published on June 20, 2014, in the journal the Cochrane Library.

Related Links:
Liverpool School of Tropical Medicine
InBios
DiaMed