Comparative study of amplification systems in immunoenzyme assays for the diagnosis of American tegumentary leishmaniasis.

We compared the accuracy and reliability of three amplification systems for enzyme immunoassays in the detection of specific IgG antibodies for the diagnosis of cutaneous leishmaniasis caused by Leishmania (Viannia) braziliensis in patients from an endemic area in Rio de Janeiro, Brazil. Partially soluble antigens obtained from the promastigote forms of L. (V.) braziliensis were used. For development of the reaction, two chromogens, 1,2-orthophenylenediamine (OPD) and 3,3',5,5'-tetramethylbenzidine (TMB), and a fluorogen, 4-methylumbelliferylphosphate (MUP), were tested. The performance of each system was compared using the following parameters: accuracy, intraclass correlation coefficient (ICC), and area under the receiver operating characteristic (ROC) curve. Sensitivity was the same (97.4%) for all systems. The reliability was excellent (ICC = 98.6, 98.7, and 99.1%) and specificity was 93.7, 95.8, and 97.4% for OPD, MUP, and TMB, respectively, showing no statistical significance. Despite the absence of differences in the performance of the three systems, the use of TMB is suggested because of its operational advantages, such as low cost compared with fluorogens, easy manipulation, greater stability, and lower toxicity.