ELECTRONIC CELL VOLUME DETERMINATION AND ITS SOURCES OF ERROR

The electronic determination of volume of the corpuscular blood components is more accurate and quicker than optical methods. The main source of error with the coulter instrument is the unequal current density in the cell-sizing aperture. This error was discovered by comparative examinations with the electron microscope, experiments using an enlarged model (electrolytic tank), and oscillographic puls shape analysis. This error in the measurement system causes the artificial positive skewness of the volume distribution curve. This error is avoided using a new device which permits exact volume determination in a homogeneous electric field without coincidence error. Form factors can be neglected in the determination of erythrocyte volume. They are only of importance in measuring the absolute volume of leukocytes as well as for calibrating instruments with latex-particles. © 1969 Springer-Verlag.