AN INVESTIGATION INTO THE PRECISION OF MICRO‐HAEMATOCRIT DETERMINATIONS OF SHEEP BLOOD
PC Dooley, RJH Morris, VJ Williams, V. J. Bofinger · Immunology and Cell Biology · 1974
Summary Decreases in micro‐haematocrit for blood from intact sheep with increases in centrifugation time at constant rev/min were observed. These decreases were analysed into two‐exponential components. Parameters for the exponential function were not related to the red cell concentration of the sample. Micro‐haematocrit of blood from splenectomized sheep decreased with increased centrifugation time in the manner of a single exponential, that was of similar magnitude to the slower exponential function found for blood from intact sheep. Delay in measuring micro‐haematocrit after the collection of a blood sample resulted in a variable, though small, decrease in micro‐haematocrit. Variations in heparin concentration between 10 and 40 i.u./ml blood, and in the mains voltage supplying the haematocrit centrifuge in the range 220 to 260 V, caused no significant effects on the value of micro‐haematocrit. The accuracy in measurement of micro‐haematocrit was similar over a wide range of red cell concentrations. These studies showed that 8 min centrifugation at 10,000 g of blood collected into dried heparin (20 i.u./ml blood) was optimal for measuring the micro‐haematocrit of sheep blood. Lengths of blood column varying between 2 and 5 cm had no significant effect with this centrifugation time.