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An International Standard for specifying the minimum potency of anti‐D blood‐grouping reagents: evaluation of a candidate preparation in an international collaborative study
Author(s) -
Thorpe S. J.,
Fox B.,
Heath A. B.,
Scott M.,
Haas M.,
Kochman S.,
Padilla A.
Publication year - 2006
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/j.1423-0410.2005.00735.x
Subject(s) - reagent , polyclonal antibodies , potency , titer , chromatography , monoclonal antibody , monoclonal , medicine , chemistry , antibody , immunology , in vitro , biochemistry , organic chemistry
Background and Objectives The aim of this study was to evaluate a lyophilized monoclonal immunoglobulin M (IgM) anti‐D preparation for use as an International Standard to specify a recommended minimum acceptable potency of anti‐D blood‐grouping reagents. Materials and Methods The candidate International Standard (99/836) for specifying the minimum potency of anti‐D blood‐grouping reagents was evaluated against a wide range of commercial anti‐D blood‐grouping reagents in an international collaborative study involving 20 laboratories in 13 countries. Laboratories titrated reconstituted 99/836, in parallel with as many commercial anti‐D blood‐grouping reagents as were available to them, in tube tests according to specified haemagglutination methodology for low‐protein (e.g. monoclonal IgM) and high‐protein (e.g. polyclonal) reagents. The ratios of the mean end‐point titres of the reagents to that of 99/836 within each laboratory were calculated. Results The ratios of the mean titres of the low‐protein reagents to the mean titre of 99/836 within a laboratory fell between 0·25 and 2 for 43 of the 45 low‐protein anti‐D reagents tested (i.e. the potencies of the low‐protein reagents compared with 99/836 were between a 1 : 4 dilution of 99/836 to twice as potent as 99/836). The ratios of the mean titres of the high‐protein reagents to the mean titre of 99/836 within a laboratory fell within 0·125 and 1 for eight out of the 10 high protein reagents tested. Conclusions By international consensus, a 1 : 3 dilution of reconstituted 99/836 was deemed appropriate to define a recommended minimum acceptable potency of low‐protein anti‐D blood‐grouping reagents. A 1 : 8 dilution of reconstituted 99/836 was deemed appropriate to define a recommended minimum acceptable potency of high‐protein anti‐D blood‐grouping reagents. On the basis of the results presented here, 99/836 was established by the World Health Organization as the 1st International Standard for specifying the minimum potency of anti‐D blood‐grouping reagents, in tube tests.