Summary of findings 1. rK39 immunochromatographic test for visceral leishmaniasis in the Indian subcontinent.

Population: Patients suspected to have visceral leishmaniasis disease 1 Setting: Health services in endemic areas of the Indian subcontinent 2 New test: rK39 immunochromatographic test 3 Reference standard: (1) direct smear test or culture of splenic aspirate; (2) composite reference standard based on one or more of the following: parasitology, serology, or response to treatment; or (3) latent class analysis 4
Pooled sensitivity: 0.97 (95% CI 0.90 to 1.00) | Pooled specificity : 0.90 (95% CI 0.76 to 0.98)
Setting 5	Positive predictive value6	Negative predictive value6	Number of participants (studies)	Quality of the evidence (QUADAS‐2) 7
Peripheral health centre with a prior probability of disease of 40%	87%	98%	1468 (6 studies)	Risk of bias: none of the studies had a low risk of bias in all domains. One study had a high risk of bias (domain of flow and timing). Five studies had an unclear risk of bias (domains of index test or reference standard). Applicability: low concerns in all studies and in all domains.
Referral centre with a prior probability of disease of 60%	94%	95%
Interpretation: When the rK39 ICT is used 1 in the Indian subcontinent, in a setting where the prior probability of VL among clinical suspects is 40%, which is typically seen in a peripheral health centre in an endemic area, the positive predictive value of the test is 87%. This means that out of 100 patients with a positive rK39 result, 87 would have VL (true positive result) and 13 would have another disease (false positive). The negative predictive value is 98%, meaning that out of 100 patients with a negative rK39 ICT result, 98 would have another disease (true negative) and 2 would have VL (false negative). When the same test is used in a setting with a prior probability of VL of 60%, which is more typical for a referral centre in an endemic area, the positive predictive value is 94% and the negative predictive value is 95%. A likelihood ratio is another way of expressing how informative a diagnostic test is: it indicates to what extent the rK39 ICT result changes the odds that a patient has VL. The likelihood ratio of a positive rK39 ICT result is 9.90, and the likelihood ratio of a negative test result is 0.03. This means that in the Indian subcontinent, a positive rK39 ICT result is a strong argument in favour of VL (ruling in) and that a negative rK39 ICT result is a strong argument against VL (ruling out).
CI: confidence interval
Boelaert M, Verdonck K, Menten J, Sunyoto T, van Griensven J, Chappuis F, Rijal S. Rapid diagnostic tests for visceral leishmaniasis. Cochrane Database of Systematic Reviews 2011, Issue 6. Art. No.: CD009135. DOI: 10.1002/14651858.CD009135.

1. The rK39 immunochromatographic test must be used in combination with a clinical case definition (fever and splenomegaly for more than two weeks and no previous history of visceral leishmaniasis). Studies with mainly HIV‐positive patients were not included in the pooled analyses.

2. The results of the meta‐analysis showed considerable heterogeneity, which was partly explained by the geographic region.

3. This rapid diagnostic test has been developed specifically for field use. It is less invasive, less time‐consuming, and easier to perform than the alternative parasitological or serological tests.

4. Latent class analysis is a modelling technique that allows us to estimate the sensitivity and specificity of a set of diagnostic tests in situations in which there is no good reference standard.

5. Two hypothetical situations: a peripheral health centre and a referral centre with a different prior probability of disease

6. A narrative explanation of the predictive values is given in Appendix 3.

7. QUADAS‐2 is a tool for the assessment of the quality of diagnostic accuracy studies. The tool comprises four domains: patient selection, index test, reference standard, and flow and timing. Each domain is assessed in terms of risk of bias, and the first three domains are also assessed in terms of concerns regarding applicability.