NINA-LAMP compared to microscopy, RDT, and nested PCR for the detection of imported malaria

Abstract

Microscopy and field adaptable rapid diagnostic tests (RDTs) are not sensitive and specific in certain conditions such as poor training of microscopists, lack of electricity, or lower sensitivity in the detection of non-falciparum malaria. More sensitive point-of-care testing (POCT) would reduce delays in diagnosis and initiation of therapy. In the current study, we have evaluated the efficacy of noninstrumented nucleic acid amplification (NINA) coupled with loop-mediated isothermal amplification (LAMP) for detection of traveler's malaria (n=140) in comparison with microscopy, nested PCR, and the only Food and Drug Administration-approved rapid diagnostic test. NINA-LAMP was 100% sensitive and 98.6% specific when compared to nested PCR. For non-falciparum detection, NINA-LAMP sensitivity was 100% sensitive compared to nested PCR, whereas RDT sensitivity was 71%. LAMP is highly sensitive and specific for symptomatic malaria diagnosis regardless of species.

Keywords: LAMP; Malaria; Point of care test.

Figure 1

Depiction of the Non-instrumented nucleic acid amplification (NINA) device used in the present study.

Figure 2

Workflow used in this study when resolving discordance (mismatch results) between the NINA-LAMP, thermal-LAMP (performed in a thermocycler), BinaxNOW (RDT), and nested PCR compared to initial microscopy for the detection of malaria parasites. Number of positive (pos) and negative (neg) results are indicated in parentheses.