リニアイメージセンサを用いたデジタル・ヘマトクリット計

抄録

A digital hematocrit-meter (DHM) was constructed for accurate determination of the hematocrit H by using a linear image sensor behind a tube holder: the holder and a tungsten lamp were settled on an optical bench. Intensity profiles from the sensor were fed into a computer through A/D converter vs. 1024 pixels along ca. 25mm length of a tube that is a coarse tube (id 1.1-1.2mm, Scientific Glass Inc.) or a fine tube (id 0.85±0.05mm, Nichiden Rika Glass Co.). Standard suspensions were prepared of swine red blood cell (RBC) in a physiological saline at H_s of ca. 8 to 60%. We determined three interfaces with 25μm resolution: air to medium, medium to packed RBC and packed RBC to patty at the bottom of the tube. The air-medium was located at minimal intensity (DHM-1) or at mean of two inflection points (DHM-2) near the end of the intensity profile, and the medium-RBC and the RBC-patty were given by inflection points. Data of H by DHM-1 and -2 were compared to the standard ones as well as H's with conventional turntable at 50mm and with cathetometer at 25mm and at 50mm full length of RBC suspensions in a tube. H's by DHM-2 in the fine tube were best correlated to the standard.