We validated the polymerase chain reaction (PCR) with a composite
reference standard in 61 patients clinically suspected of having
mucosal leishmaniasis, 36 of which were cases and 25 non-cases
according to this reference standard. Patient classification and test
application were carried out independently by two blind observers. One
pair of primers was used to amplify a fragment of 120 bp in the
conserved region of kDNA and another pair was used to amplify the
internal transcript spacers (ITS) rDNA. PCR showed 68.6% (95% CI
59.2-72.6) sensitivity and 92% (95% CI 78.9-97.7) specificity; positive
likelihood ratio: 8.6 (95% CI 2.8-31.3) and negative likelihood ratio:
0.3 (95% CI 0.3-0.5), when kDNA molecular target was amplified. The
test performed better on sensitivity using this target compared to the
ITS rDNA molecular target which showed 40% (95% CI 31.5-42.3)
sensitivity and 96% (95% CI 84.1-99.3) specificity; positive likelihood
ratio: 10 (95% CI 2.0-58.8) and negative likelihood ratio: 0.6 (95% CI
0.6-0.8). The inter-observer agreement was excellent for both tests.
Based upon results obtained and due to low performance of conventional
methods for diagnosing mucosal leishmaniasis, we consider PCR with kDNA
as molecular target is a useful diagnostic test and the ITS rDNA
molecular target is useful when the aim is to identify species
