Comparison of the rheological behavior of hemocytometry controls and fresh patient EDTA-anticoagulated blood specimens.

ABSTRACT

For rheological reasons high viscosity specimens are more sensitive to deficiencies, if any, in the aspiration systems of whole blood flow cytometers and consequently are more likely to give erroneous values. For this reason the rheological behavior of hemocytometry controls was compared with that of patient blood specimens. It is shown that the behavior of controls and patient specimens of comparable hematocrit is similar at shear rates that are probably occurring during aspiration (exceeding approximately 40 s-1). The hematocrit is shown to be a major determinant of the viscosity of both controls and patient specimens. The results suggest that from the rheological point of view the fundamental IFCC premise is met, "that errors detected by means of control specimens exactly mirror errors occurring with patients' specimens", provided their hematocrits are taken into account.