title: Comparison of influenza serological techniques by international collaborative study.
abstract: An international collaborative study was performed to investigate the reproducibility of influenza serological techniques. Participants in seven laboratories representing five countries measured antibody to A/Sichuan/2/87 (H3N2), A/Taiwan/1/86 (H1N1) and B/Beijing/1/87 influenza viruses in 11 human sera and three postinfection ferret sera. Two different serological techniques were used, haemagglutination inhibition (HI) and single-radial haemolysis (SRH) and, although each technique was reproducible within laboratories, variability between laboratories was higher for HI (maximum variability 32-fold; geometric coefficient of variation, GCV, 112%) than for SRH (maximum variability 3.8-fold; GCV 57%). The use of a standard serum allowed direct comparison of HI and SRH data and, for each technique, a standard serum improved inter-laboratory agreement. For influenza A viruses there was a correlation between HI and SRH antibodies (correlation coefficient approximately 0.9). An HI titre of 1:40 in human sera corresponded to an SRH titre of 19-33 mm2. The results of the study indicate that two sera would be expected to contain different antibody levels if their HI titres differed by > fourfold and SRH areas differed by > 50%. Both SRH and HI possessed equivalent sensitivity for measurement of antibody to influenza A viruses but SRH was more sensitive for detection of antibody to influenza B viruses. The study provided valuable information about standardization of antibody assays.
authors.affiliation: National Institute for Biological Standards and Control, Hertfordshire, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Wood
authors.forename: R E
authors.initials: RE
authors.lastname: Gaines-Das
authors.forename: J
authors.initials: J
authors.lastname: Taylor
authors.forename: P
authors.initials: P
authors.lastname: Chakraverty
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D005289:Ferrets; D006385:Hemagglutination Inhibition Tests / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D006462:Hemolytic Plaque Technique / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D009980:Influenza A virus / Q000276:immunology; D009981:Influenza B virus / Q000276:immunology; D007251:Influenza, Human / Q000276:immunology*; D007391:International Cooperation; D007753:Laboratories; D009975:Orthomyxoviridae / Q000276:immunology; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral