New electronic method for measuring hematocrit: clinical evaluation.

Abstract

Abstract A new rapid electronic method for measuring hematocrit utilizes the principle that the electrical resistance of a column of blood is a function of the relative volume per cent of erythrocytes. A description is presented of a small light electronic instrument which is portable, completely transistorized, and powered only by a standard transistor radio battery; it measures the resistance of a small column of blood in a plastic cuvette. A clinical evaluation of this instrument compared the hematocrit of eighty-seven patients' finger-tip capillary blood measured by this instrument with that measured by a standard centrifuged microhematocrit technique. There was no clinically significant systematic difference between the two methods (mean difference of 1.0 hematocrit per cent units); the standard deviation was ± 3.0 hematocrit per cent units. In experiments using reconstituted blood of different protein concentration, it is shown that the reading is subject to correction in patients suspected of having abnormally large deviation in total serum protein concentration. This new technique is useful in circumstances requiring very rapid hematocrit determination or where a centrifuge or electric power source is not available.