Collaborative studies to establish the first WHO Reference Reagent for detection of human antibody against human platelet antigen-5b.
OBJECTIVE
This report describes the production of a freeze-dried preparation of pooled human plasma, coded 99/666, containing immunoglobulin G (IgG) antibodies against human platelet antigen 5b (HPA-5b).


METHODS
The material is intended for use as a minimum sensitivity reagent in the assays currently used for detection of antibodies to HPA-5b. Laboratories can use it to assess the sensitivity of their 'in-house' assays for antibodies to HPA-5b and to calibrate local controls for routine use in each batch of tests.


RESULTS
Two collaborative studies demonstrated that the two candidate materials contained antibodies to HPA-5b and that there were no other HPA or human leucocyte antigen (HLA) antibodies which might confuse the detection of antibodies to HPA-5b. The two samples were pooled and freeze-dried in 1-ml ampoules.


CONCLUSIONS
The minimum dilution of the antibody against 5b required to yield a positive result was determined, by two international collaborative studies involving a total of 49 laboratories in 26 countries, to be 1 in 2.
Metcalfe
P
P
Division of Haematology, National Institute for Biological Standards and Control, South Mimms, Potters Bar, Herts, UK. pmetcalfe@nibsc.ac.uk
Ouwehand
W H
WH
Sands
D
D
Barrowcliffe
T W
TW
D000911:Antibodies, Monoclonal / Q000302:isolation & purification; D016824:Antigens, Human Platelet / Q000276:immunology*; D003299:Cooperative Behavior; D005612:Freeze Drying; D006801:Humans; D007074:Immunoglobulin G / Q000302:isolation & purification; D007202:Indicators and Reagents / Q000592:standards; D007518:Isoantibodies / Q000097:blood*; D012015:Reference Standards; D012680:Sensitivity and Specificity; D014944:World Health Organization
C055973:5b alloantigen, human; D000911:Antibodies, Monoclonal; D016824:Antigens, Human Platelet; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D007518:Isoantibodies