Preparation of standards for quality control of the measurement of erythrocyte deformability (filterability)

Measurements of blood rheology in clinical studies should incorporate a quality control programme and, for this purpose, we have studied three approaches to the preparation of an erythrocyte standard. Partial fixation of erythrocytes using 0.04% w/v formaldehyde at ambient temperature, followed by storage at 4°C, provided an erythrocyte suspension which gave stable 5 µm pore filtration values for up to 4 weeks. Incubation of erythrocytes with a monoclonal antibody (BRIC 14) to membrane Glycophorin A caused impairment of filterability which was maintained for up to 11 days. A cross-linked acrylic copolymer, comprising soft spheres of 5–8 µm diameter, was also developed as an erythrocyte substitute for filtration studies. This pilot study indicates the potential for development of an international reference standard for rheological studies.