Diagnostic accuracy of loopamp Trypanosoma brucei detection kit for diagnosis of human African trypanosomiasis in clinical samples

PLoS Negl Trop Dis. 2013 Oct 17;7(10):e2504. doi: 10.1371/journal.pntd.0002504. eCollection 2013.

Abstract

Background: Molecular methods have great potential for sensitive parasite detection in the diagnosis of human African trypanosomiasis (HAT), but the requirements in terms of laboratory infrastructure limit their use to reference centres. A recently developed assay detects the Trypanozoon repetitive insertion mobile element (RIME) DNA under isothermal amplification conditions and has been transformed into a ready-to-use kit format, the Loopamp Trypanosoma brucei. In this study, we have evaluated the diagnostic performance of the Loopamp Trypanosoma brucei assay (hereafter called LAMP) in confirmed T.b. gambiense HAT patients, HAT suspects and healthy endemic controls from the Democratic Republic of the Congo (DRC).

Methodology/principal findings: 142 T.b. gambiense HAT patients, 111 healthy endemic controls and 97 HAT suspects with unconfirmed status were included in this retrospective evaluation. Reference standard tests were parasite detection in blood, lymph or cerebrospinal fluid. Archived DNA from blood of all study participants was analysed in duplicate with LAMP. Sensitivity of LAMP in parasitologically confirmed cases was 87.3% (95% CI 80.9-91.8%) in the first run and 93.0% (95% CI 87.5-96.1%) in the second run. Specificity in healthy controls was 92.8% (95% CI 86.4-96.3%) in the first run and 96.4% (95% CI 91.1-98.6%) in the second run. Reproducibility was excellent with a kappa value of 0.81.

Conclusions/significance: In this laboratory-based study, the Loopamp Trypanosoma brucei Detection Kit showed good diagnostic accuracy and excellent reproducibility. Further studies are needed to assess the feasibility of its routine use for diagnosis of HAT under field conditions.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood / parasitology
  • Cerebrospinal Fluid / parasitology
  • Humans
  • Lymph / parasitology
  • Molecular Diagnostic Techniques / methods*
  • Nucleic Acid Amplification Techniques / methods*
  • Parasitology / methods*
  • Reproducibility of Results
  • Retrospective Studies
  • Sensitivity and Specificity
  • Trypanosoma brucei brucei / genetics
  • Trypanosoma brucei brucei / isolation & purification*
  • Trypanosomiasis, African / diagnosis*

Grant support

FIND, the sponsor of the development of the LAMP kit, provided the required kits and reagents for this study. The views expressed by the authors do not necessarily reflect the views of the funding agency. The biological specimens were collected in collaboration with the National Human African Trypanosomiasis Control Program (PNLTHA) of the D.R. Congo, in a study financed by the Secondary Research Funding of the Institute of Tropical Medicine (HAT PolyB) and a study financed by the Belgian Directorate General for Development Cooperation. PM and PPP received a PhD grant and DMN received a Post-Doc grant from the Belgian Directorate General for Development Cooperation. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.