Measuring apparatus for the determination of the ratio of the volume of the in a blood sample existing blood body chen to the total volume of the blood sample a centrifuge and such a process index

摘要

1,162,941. Measuring hematocrit index of blood electrically. COULTER ELECTRONICS Ltd. Oct. 13, 1966 [Oct. 20, 1965], No.45896/66. Heading G1N. Apparatus for automatically measuring the ratio of the total volume of red cells of a given sample of whole blood to the total volume of that sample comprises a Coulter type of cell counting and sizing apparatus 10, having a first output channel 38 which delivers cell counting information to an integrator 23 and a second output channel 34 which delivers cell counting and cell sizing information to a mean cell volume computer 22, and an analog computer 75 for multiplying the cell count by the mean cell volume thereby to determine the hematocrit index. As shown in Fig. 1, a metering device 20, such as described in Specification 865, 069, delivers a known volume of a sample comprising blood diluted with an electrolyte to a Coulter scanner 12, such as described in Specification 907, 028. The output of integrator 23 is corrected in accordance with known statistics for coincidence (two cells being detected together) before being applied across terminals 71, 72 of a potentiometer 58. The wiper of the potentiometer is driven by a motor 49 forming part of a servoamplifier and its position is dependent on the mean cell volume whereby the voltage of the wiper tap 60 is proportional to the hematocrit index. This voltage is passed to a second servo-amplifier wherein the angular position of a scale 83 relative to an index mark 84 indicates the hematocrit index. A common reference voltage 63 is used for both servo-amplifiers. The integrator 23 may be arranged to de-energize the detecting means when the integrator has become saturated.