WHO endorses first international standard for Plasmodium falciparum antigens

  • FIND collaborates with NIBSC to develop international standard for diagnostics detecting P. falciparum HRP2 and pLDH antigens

In endemic regions, malaria is generally diagnosed using malaria rapid diagnostic tests (RDTs). These tests, which are affordable and easy to use in remote areas, are based on the detection in blood of two P. falciparum antigens: histidine-rich protein 2 (HRP2) and Plasmodium lactate dehydrogenase (pLDH).

The ability to evaluate RDT performance reliably and accurately using an internationally recognized reference standard (IS) is critical. International standards enable product comparison and procurement decisions, guide local quality control procedures and promote the development and testing of novel RDTs.

FIND partnered with the National Institute for Biological Standards and Control (NIBSC) to create the first World Health Organization (WHO) IS for P. falciparum antigens by conducting an international collaborative study in 13 laboratories across 11 different countries. FIND provided funding for the study, contributed to the development of protocols and standard operating procedures, identified key partners, and facilitated the selection and transfer of clinical samples from the WHO specimen bank.

The IS that was validated by the study and subsequently endorsed by the WHO Expert Committee on Biological Standardization (ECBS) on 19 October and has been established at International Units of the P. falciparum antigens HRP-2 and pLDH per ampoule. On the same day, WHO ECBS endorsed proposals for “the first International Standard for Plasmodium vivax antigens” and “the first WHO Reference Reagent for Anti-Malaria (Plasmodium vivax) human serum.” FIND will collaborate with the NIBSC on the development of these standards, providing funds and raw materials for evaluation.

These standards will be used worldwide for the quality control and regulation of RDTs and similar in vitro assays. They will also be used to support the development of more sensitive RDTs and to calibrate other reference materials and controls, including panels of recombinant proteins and positive wells being developed by FIND. The calibration of recombinant panels is a key use of the IS for the new WHO decentralized RDT lot testing programme, which relies on these panels as a substitute for patient samples to lower costs and increase sustainability of malaria RDT quality control procedures.

This project was made possible through the support of the Bill & Melinda Gates Foundation, UK aid from the UK government and the Australian Government.

About NIBSC
NIBSC is a centre of the Medicines and Healthcare products Regulatory Agency which also includes the Clinical Practice Research Datalink (CPRD). The Agency is an executive agency of the Department of Health.

About FIND
FIND is an international non-profit organization based in Geneva, Switzerland. The organization is dedicated to activities that result in: 1) new diagnostic tools for poverty-related diseases in low- and middle-income countries; 2) expanded access to these tools; and 3) strengthened diagnostic testing capacity in low- and middle-income countries.