Accordance and concordance of PCR and NASBA followed by oligochromatography for the molecular diagnosis of Trypanosoma brucei and Leishmania

To evaluate the repeatability and reproducibility of four simplified molecular assays for the diagnosis of Trypanosoma brucei spp. or Leishmania ssp. in a multicentre ring trial with seven participating laboratories. The tests are based on PCR or NASBA amplification of the parasites nucleic acids followed by rapid read-out by oligochromatographic dipstick (PCR-OC and NASBA-OC). On purified nucleic acid specimens, the repeatability and reproducibility of the tests were Tryp-PRC-OC, 91.7% and 95.5%; Tryp-NASBA-OC, 95.8% and 100%; Leish-PCR-OC, 95.9% and 98.1%; Leish-NASBA-OC, 92.3% and 98.2%. On blood specimens spiked with parasites, the repeatability and reproducibility of the tests were Tryp-PRC-OC, 78.4% and 86.6%; Tryp-NASBA-OC, 81.5% and 89.0%; Leish-PCR-OC, 87.1% and 91.7%; Leish-NASBA-OC, 74.8% and 86.2%. As repeatability and reproducibility of the tests were satisfactory, further phase II and III evaluations in clinical and population specimens from disease endemic countries are justified.