BCSH-NIBSC anti-D reference reagent for antiglobulin tests: the in-house assessment of red cell washing centrifuges and of operator variability in the detection of weak, macroscopic agglutination. British Committee for Standards in Haematology. National Institute for Biological Standards and Control.
A batch of an anti-D preparation, reference 91/608, has been prepared for the preparation of red cells weakly sensitized with IgG that can reveal inhibition of the antiglobulin test by one volume of human serum, diluted 1:1000. The preparation provides an objective assessment of red cell washer efficacy and the confidential, in-house assessment of operator variability in detecting weak but definite macroscopic agglutination by blind, replicate tests. Red cell washer efficacy and poor operator reading procedures causing disruption of weak agglutination are two major causes of false-negative antiglobulin tests; neither are adequately detected by the common quality-control procedure of adding strongly IgG-sensitized red cells ('Coombs control cells') to apparently negative antiglobulin tests. However, weakly IgG-sensitized red cells do offer a valuable control function that can detect some degree of cell washer inefficiency and reading errors although such cells are not a substitute for the more sensitive replicate testing. Test protocols are provided to assess the efficacy of cell washing machines and operator skills in the detection of weak but definite macroscopic agglutination.
National Institute for Biological Standards and Control, Potters Bar, U.K.
P K
PK
Phillips
D
D
Voak
C M
CM
Whitton
D M
DM
Downie
C
C
Bebbington
J
J
Campbell
D016477:Artifacts; D001788:Blood Grouping and Crossmatching / Q000379:methods / Q000592:standards*; D002498:Centrifugation / Q000295:instrumentation*; D003298:Coombs Test / Q000295:instrumentation / Q000592:standards*; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D005189:False Positive Reactions; D006384:Hemagglutination; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007136:Immunoglobulins; D015588:Observer Variation; D011786:Quality Control; D012015:Reference Standards; D018029:Rho(D) Immune Globulin
D007074:Immunoglobulin G; D007136:Immunoglobulins; D018029:Rho(D) Immune Globulin