Hepatitis A immunoglobulin: an international collaborative study to establish the second international standard.
A collaborative study was carried out to assess the suitability of a candidate replacement material for the International Standard for hepatitis A immunoglobulin, which was found to be reactive for HCV RNA, and to calibrate it in International Units. The candidate standard, coded 97/646, was derived from a bulk of 16% immunoglobulin supplied by the Central Laboratory of the Netherlands Red Cross, Amsterdam, and diluted 1 in 2 in H2O resulting in a final immunoglobulin concentration of 8%. Sixteen laboratories from 11 countries participated in the study and contributed data from 64 assays performed using six commercial assay kits and four in-house methods. All assays were analysed as parallel line bioassays comparing assay response with log concentration. The overall mean potency of the candidate replacement immunoglobulin standard, 97/646, relative to the International Standard for hepatitis A immunoglobulin, was 98.6 IU/ml. A freeze-dried serum preparation, 97/648, was also calibrated in this study and had a potency of 22.64 IU/ml. The Second International Standard for hepatitis A immunoglobulin, human, was established by the World Health Organisation Expert Committee on Biological Standardisation in 1998 with a potency of 49 IU per ampoule when reconstituted in 0.5 ml.
Ferguson
M
M
National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Herts, EN6 3QG, UK. mferguson@nibsc.ac.uk
Sands
D
D
Lelie
N
N
D001681:Biological Assay / Q000379:methods / Q000592:standards / Q000706:statistics & numerical data; D004355:Drug Stability; D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies / Q000032:analysis*; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis*; D007391:International Cooperation; D007753:Laboratories; D009426:Netherlands; D012015:Reference Standards; D014944:World Health Organization
D035922:Hepatitis A Antibodies; D006508:Hepatitis Antibodies; D007136:Immunoglobulins