Malaria rapid diagnostic tests: Plasmodium falciparum infections with high parasite densities may generate false positive Plasmodium vivax pLDH lines

J Maltha, P Gillet, L Cnops, J Van den Ende, M Van Esbroeck, J Jacobs

    Research output: Contribution to journalA1: Web of Science-article

    Abstract

    ABSTRACT: BACKGROUND: Most malaria rapid diagnostic tests (RDTs) detect Plasmodium falciparum and an antigen common to the four species. Plasmodium vivax-specific RDTs target P. vivax-specific parasite lactate dehydrogenase (Pv-pLDH). Previous observations of false positive Pv-pLDH test lines in P. falciparum samples incited to the present study, which assessed P. vivax-specific RDTs for the occurrence of false positive Pv-pLDH lines in P. falciparum samples. METHODS: Nine P. vivax-specific RDTs were tested with 85 P. falciparum samples of high (>/=2%) parasite density. Mixed P. falciparum/P. vivax infections were ruled out by real-time PCR. The RDTs included two-band (detecting Pv-pLDH), three-band (detecting P. falciparum-antigen and Pv-pLDH) and four-band RDTs (detecting P. falciparum, Pv-pLDH and pan-pLDH). RESULTS: False positive Pv-pLDH lines were observed in 6/9 RDTs (including two- three- and four-band RDTs). They occurred in the individual RDT brands at frequencies ranging from 8.2% to 29.1%. For 19/85 samples, at least two RDT brands generated a false positive Pv-pLDH line. Sixteen of 85 (18.8%) false positive lines were of medium or strong line intensity. There was no significant relation between false positive results and parasite density or geographic origin of the samples. CONCLUSION: False positive Pv-pLDH lines in P. falciparum samples with high parasite density occurred in 6/9 P. vivax-specific RDTs. This is of concern as P. falciparum and P. vivax are co-circulating in many regions. The diagnosis of life-threatening P. falciparum malaria may be missed (two-band Pv-pLDH RDT), or the patient may be treated incorrectly with primaquine (three- or four-band RDTs)
    Original languageEnglish
    JournalMalaria Journal
    Volume9
    Pages (from-to)198
    Number of pages7
    ISSN1475-2875
    DOIs
    Publication statusPublished - 2010

    Keywords

    • B780-tropical-medicine
    • Protozoal diseases
    • Malaria
    • Plasmodium falciparum
    • Plasmodium vivax
    • Vectors
    • Mosquitoes
    • Diagnostics
    • Rapid diagnostic tests
    • False-positive
    • Parasite density
    • Accuracy
    • Laboratory techniques and procedures

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