Estimating the Added Utility of Highly Sensitive Histidine-Rich Protein 2 Detection in Outpatient Clinics in Sub-Saharan Africa

Am J Trop Med Hyg. 2017 Oct;97(4):1159-1162. doi: 10.4269/ajtmh.17-0262. Epub 2017 Jul 19.

Abstract

Most malaria testing is by rapid diagnostic tests (RDTs) that detect Plasmodium falciparum histidine-rich protein 2 (HRP2). Recently, several RDT manufacturers have developed highly sensitive RDTs (hsRDTs), promising a limit of detection (LOD) orders of magnitude lower than conventional RDTs. To model the added utility of hsRDTs, HRP2 concentration in Angolan outpatients was measured quantitatively using an ultrasensitive bead-based assay. The distribution of HRP2 concentration was bimodal in both afebrile and febrile patients. The conventional RDT was able to detect 81% of all HRP2-positive febrile patients and 52-77% of HRP2-positive afebrile patients. The added utility of hsRDTs was estimated to be greater in afebrile patients, where an hsRDT with a LOD of 200 pg/mL would detect an additional 50-60% of HRP2-positive persons compared with a conventional RDT with a LOD of 3,000 pg/mL. In febrile patients, the hsRDT would detect an additional 10-20% of cases. Conventional RDTs already capture the vast majority of symptomatic HRP2-positive individuals, and hsRDTs would have to reach a sufficiently low LOD approaching 200 pg/mL to provide added utility in identifying HRP2-positive, asymptomatic individuals.

MeSH terms

  • Angola / epidemiology
  • Antigens, Protozoan / blood*
  • Fever / diagnosis
  • Humans
  • Immunoassay / methods
  • Limit of Detection*
  • Malaria, Falciparum / blood*
  • Malaria, Falciparum / diagnosis*
  • Malaria, Falciparum / epidemiology
  • Protozoan Proteins / blood*

Substances

  • Antigens, Protozoan
  • HRP-2 antigen, Plasmodium falciparum
  • Protozoan Proteins