A PARALLEL COMPARISON OF 3 AUTOMATED MULTICHANNEL BLOOD-CELL COUNTINGSYSTEMS FOR ANALYSIS OF BLOOD OF LABORATORY-ANIMALS

A parallel evaluation was performed on three automated haematology ana lysers, the Sysmex K-4500 and Coulter Counter S-PLUS STKR impedance an alysers, and the Techinicon H1E flow cytometry analyser. The same blo od samples from animals from three different species were analysed on the same day. An analytical comparison of haemograms from healthy monk eys, dogs, rats and phlebotomised rats was made from paired blood samp les anticoagulated with dipotassium ethylenediaminetetra-acetate. Each instrument was calibrated with commercially available material based on human blood products. The precision of each system was good, but wh ereas the Coulter Counter S-PLUS STKR had better precision for white b lood cell counts, platelet counts showed greater variability. When com pared to spun packed cell volume (PCV), or to each of the other instru ments, the Coulter system consistently gave lower haematocrit values. The magnitude of relative bias of spun PCV values was about -7% in mon key, -5% in dogs and -10% in rats. It was deemed necessary with this i nstrument to make adjustments to the calibration, especially for rats. The Coulter also gave consistently higher white blood cells (WBC) cou nts in monkeys, and lower platelet counts in rats compared to the othe r two instruments. The biases may be due to inherent physical differen ces between the analytical methods and/or the calibration techniques. With few exceptions, each instrument provides reliable results for all major animal species encountered in routine experimental and toxicolo gical haematology.