Predonation hematocrit measurement by whole blood electrical conductivity assay.

The whole blood electrical conductivity method for predonation hematocrit determinations was studied. Forty capillary and venous blood samples were tested concurrently with electrical conductivity and centrifugation methods. The electrical conductivity method demonstrated acceptable accuracy but was less precise than the spun microhematocrit technique. Results from capillary samples were uniformly less precise and significantly lower than determinations from venous specimens. This study and previous reports suggest that capillary hematocrit values by any method may not accurately reflect the blood donor's venous hematocrit level. Blood centers should independently validate their anemia screening methods to avoid unnecessary deferrals and protect the anemic donor.