Assignment of assay values to Coulter controls and calibrators

The whole blood reference specimens are carefully selected in order to minimize errors in either reference methods or the assay method that might be produced by interferants in the specimens. Fundamental to the process of assigning values to calibrators and controls is the rule that fresh whole blood from normal donors be used as the transfer medium between reference measurement methods and the automated blood cell counter that will be used to assay the stabilized whole blood product. Increasing recognition is being given to the need to adopt K2EDTA salts as global standards for reference specimen anticoagulant. The reference methods used by Coulter closely follow the methods recommended by the Cytometry Panel of the International Committee for Standardization in Haematology and by the National Committee for Clinical Laboratory Standards. Methods used for the statistical control of value assignment are appropriate for commercial rather than institutional use. Simplification of methods is possible because of high levels of test replication and the homogeneous nature of stabilized blood products.