Analysis of nucleic acids extracted from rapid diagnostic tests reveals a significant proportion of false positive test results associated with recent malaria treatment

• Published in: Malaria Journal
• Main Authors: Salome Hosch, Charlene Aya Yoboue, Olivier Tresor Donfack, Etienne A. Guirou, Jean-Pierre Dangy, Maxmillian Mpina, Elizabeth Nyakurungu, Koranan Blöchliger, Carlos A. Guerra, Wonder P. Phiri, Mitoha Ondo’o Ayekaba, Guillermo A. García, Marcel Tanner, Claudia Daubenberger, Tobias Schindler
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Molecular malaria surveillance; False-positive malaria rapid diagnostic test; PfHRP2 persistence; pfhrp2 gene deletion; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04043-7; https://doaj.org/article/b50c2080569c47f88fa80bf56cc91fb5

Abstract Background Surveillance programmes often use malaria rapid diagnostic tests (RDTs) to determine the proportion of the population carrying parasites in their peripheral blood to assess the malaria transmission intensity. Despite an increasing number of reports on false-negative and false-positive RDT results, there is a lack of systematic quality control activities for RDTs deployed in malaria surveillance programmes. Methods The diagnostic performance of field-deployed RDTs used for malaria surveys was assessed by retrospective molecular analysis of the blood retained on the tests. Results Of the 2865 RDTs that were collected in 2018 on Bioko Island and analysed in this study, 4.7% had a false-negative result. These false-negative RDTs were associated with low parasite density infections. In 16.6% of analysed samples, masked pfhrp2 and pfhrp3 gene deletions were identified, in which at least one Plasmodium falciparum strain carried a gene deletion. Among all positive RDTs analysed, 28.4% were tested negative by qPCR and therefore considered to be false-positive. Analysing the questionnaire data collected from the participants, this high proportion of false-positive RDTs could be explained by P. falciparum histidine rich protein 2 (PfHRP2) antigen persistence after recent malaria treatment. Conclusion Malaria surveillance depending solely on RDTs needs well-integrated quality control procedures to assess the extent and impact of reduced sensitivity and specificity of RDTs on malaria control programmes.