Comparison of influenza serological techniques by international collaborative study

Vaccine. 1994 Feb;12(2):167-74. doi: 10.1016/0264-410x(94)90056-6.


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.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Antibodies, Viral / blood*
  • Ferrets
  • Hemagglutination Inhibition Tests / methods*
  • Hemagglutination Inhibition Tests / standards
  • Hemagglutination Inhibition Tests / statistics & numerical data
  • Hemolytic Plaque Technique* / standards
  • Hemolytic Plaque Technique* / statistics & numerical data
  • Humans
  • Influenza A virus / immunology
  • Influenza B virus / immunology
  • Influenza, Human / immunology*
  • International Cooperation
  • Laboratories
  • Orthomyxoviridae / immunology
  • Reference Standards
  • Reproducibility of Results
  • Sensitivity and Specificity


  • Antibodies, Viral