A novel pan-Leishmania loop-mediated isothermal amplification (Loopamp) assay for diagnosis of cutaneous and visceral leishmaniasis: a systematic review and meta-analysis.

BACKGROUND

There is an urgent need for accurate and robust point-of-care (PoC) assays for visceral and cutaneous leishmaniasis (VL and CL). The Loopamp™ Leishmania detection kit (Loopamp), a novel loop-mediated isothermal amplification (LAMP) assay, has shown promise for VL and CL diagnosis using Qiagen and simpler boil-and-spin (B&S) DNA extraction methods. But diagnostic performances were inconsistent across studies. This systematic review and meta-analysis aimed to evaluate the pooled sensitivity and specificity of Loopamp for CL and VL diagnosis.

METHODS

A comprehensive search of PubMed, Scopus, EMBASE, and Google Scholar was conducted to identify studies that evaluated the diagnostic performance of Loopamp for VL and CL suspects. Using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), the methodological qualities of the included studies were evaluated. A bivariate random-effects meta-analysis was performed using R and Stata 14.2.

RESULTS

Ten studies comprising 18 datasets were included. Sensitivity among individual VL studies ranged from 92 to 100%, while specificity varied from 41 to 100%. For CL, sensitivity varied from 48 to 100% and specificity from 31 to 100%. Pooled sensitivity was 96% (95% CI, 94-98%) for VL and 93% (95% CI, 70-99%) for CL. Pooled specificity was 99% (95% CI, 94-100%) for VL and 87% (95% CI, 55-97%) for CL. Subgroup analysis revealed that whole-blood B&S-Loopamp for VL had similar sensitivity (96%, 95% CI: 93-98%) and specificity (99%, 95% CI: 89-100%) to Qiagen-Loopamp.

CONCLUSIONS

Loopamp demonstrated robust diagnostic performance for VL in whole blood, meeting the 95% sensitivity and 99% specificity criteria outlined in the Target Product Profile (TPP). Similar to Loopamp-Qiagen, Loopamp-B&S performed excellently for VL diagnosis and is feasible to deploy in remote endemic areas. Loopamp showed high sensitivity and good specificity for CL diagnosis but fell short of the 95% sensitivity and 90% specificity required for CL PoC tests. Data on CL are limited, and its effectiveness in New World VL patients is unclear. Future research is needed to address this gap.

TRIAL REGISTRATION: CRD42023489463.