False-negative RDT results and implications of new reports of P. falciparum histidine-rich protein 2/3 gene deletions
In 2010, a study sponsored by WHO and FIND found that some P. falciparum parasites in Peru lacked the pfhrp2 gene; without this gene, the parasite cannot produce HRP2 and cannot be detected by HRP2-based rapid diagnostic tests (RDTs). This was the first report to confirm the absence of the pfhrp2 gene among P. falciparum parasites in a clinical setting.
More recently, surveys in several African settings have also found a varying proportion of P. falciparum parasites lacking the pfhrp2 gene. The prevalence of this genetic mutation reportedly varies between and within countries; if confirmed, RDT procurement and case management practices will need to be tailored accordingly.
This information note provides countries with specific guidance on how to investigate suspected false negative RDT results, including pfhrp2 gene deletions, and on alternative non-HRP2-based RDT options.
- WHO investigates reports of missing gene among malaria parasites and possible impact on RDT performance
- Information note on recommended selection criteria for procurement of malaria rapid diagnostic tests (RDTs)