title: Calibration and commutability assessment of the 1st International Standard for Diphtheria Antitoxin Human.
abstract: The 1st International Standard for Diphtheria Antitoxin Human (coded 10/262) was established by the World Health Organization Expert Committee on Biological Standardization in 2012. This paper describes the production, characterization and calibration of the new standard which is intended for use in the standardization of assays used to measure diphtheria antibody responses in human serum. The new standard was calibrated in terms of the International Standard for Diphtheria Antitoxin Equine in an international collaborative study. A total of 8 participants from 8 different countries performed in vivo and/or in vitro toxin neutralization tests and returned data that was used to assign units to the proposed new standard. The new standard has a diphtheria antitoxin potency of 2 IU/ampoule and is predicted to be stable. A follow up study was performed to assess commutability of the new standard. The follow up study was an existing external quality assessment, modified to include the new standard. Results obtained suggest that the new standard is commutable, showing comparable behaviour to native human serum samples in the majority of the assays compared, and is therefore suitable for use as a reference preparation in assays used to measure the level of anti-diphtheria antibodies in human serum.
authors.affiliation: Division of Bacteriology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, UK. Electronic address: Paul.Stickings@nibsc.org.
authors.forename: Paul
authors.initials: P
authors.lastname: Stickings
authors.forename: Peter
authors.initials: P
authors.lastname: Rigsby
authors.forename: Laura
authors.initials: L
authors.lastname: Coombes
authors.forename: Christina
authors.initials: C
authors.lastname: von Hunolstein
authors.forename: Luisa
authors.initials: L
authors.lastname: Ralli
authors.forename: Antonella
authors.initials: A
authors.lastname: Pinto
authors.forename: Dorothea
authors.initials: D
authors.lastname: Sesardic
mesh_terms: D000818:Animals; D002138:Calibration; D002522:Chlorocebus aethiops; D004166:Diphtheria Antitoxin / Q000097:blood* / Q000276:immunology*; D004355:Drug Stability; D005612:Freeze Drying; D006168:Guinea Pigs; D006736:Horses; D006801:Humans; D007391:International Cooperation; D009500:Neutralization Tests / Q000379:methods / Q000592:standards*; D012015:Reference Standards; D014709:Vero Cells; D014944:World Health Organization
chemical_list: D004166:Diphtheria Antitoxin
keywords: Antibody; Antitoxin; Diphtheria; ELISA; Immunoassay; Serology