Establishment of the 1 st World Health Organization International Standard for Plasmodium falciparum DNA for nucleic acid amplification technique (NAT)-based assays

• Published in: Malaria Journal
• Main Authors: Chiodini Peter L, Sutherland Colin, Heath Alan B, Padley David J, Baylis Sally A
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2008
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-7-139; https://doaj.org/article/b8ebbb0a3af9474dbb83f7a39033c618

Abstract Background In order to harmonize results for the detection and quantification of Plasmodium falciparum DNA by nucleic acid amplification technique (NAT)-based assays, a World Health Organization (WHO) collaborative study was performed, evaluating a series of candidate standard preparations. Methods Fourteen laboratories from 10 different countries participated in the collaborative study. Four candidate preparations based upon blood samples parasitaemic for P. falciparum were evaluated in the study. Sample AA was lyophilized, whilst samples BB, CC and DD were liquid/frozen preparations. The candidate standards were tested by each laboratory at a range of dilutions in four independent assays, using both qualitative and quantitative NAT-based assays. The results were collated and analysed statistically. Results Twenty sets of data were returned from the participating laboratories and used to determine the mean P. falciparum DNA content for each sample. The mean log 10 "equivalents"/ml were 8.51 for sample AA, 8.45 for sample BB, 8.35 for sample CC, and 5.51 for sample DD. The freeze-dried preparation AA, was examined by accelerated thermal degradation studies and found to be highly stable. Conclusion On the basis of the collaborative study, the freeze-dried material, AA (NIBSC code No. 04/176) was established as the 1 st WHO International Standard for P. falciparum DNA NAT-based assays and has been assigned a potency of 10 9 International Units (IU) per ml. Each vial contains 5 × 10 8 IU, equivalent to 0.5 ml of material after reconstitution.