Modification and evaluation of a multichannel blood cell counting system for blood analysis in veterinary hematology.

The research article presents a study that modified a multichannel blood cell counting system for use in veterinary hematology, increased the red and white blood cell aperture currents, calibrated it using human blood, and tested it on samples from multiple animal species. The results indicate how successfully the leukocyte size, erythrocyte count, mean corpuscular volume, and hematocrit were measured compared to reference procedures.

Research Methods and Process

• The researchers modified a multichannel, semi-automatic blood cell counting system, specifically the Coulter Counter Model S550, to suit veterinary hematology operations.
• To achieve this, the team increased the erythrocyte (red blood cell) and leukocyte (white blood cell) aperture currents to 225V and 195V, respectively.
• To validate its functionality, it was calibrated using human blood first.
• The modified instrument was evaluated using 350 samples of blood from different specie: dogs, cats, horses, and cows.

Results and Comparisons

• The values for leukocyte count, erythrocyte count, mean corpuscular volume, and hematocrit that the modified S550 produced were compared with values generated by an automated multichannel counter with histogram capability, and other established methods as well.
• The researchers discovered that mean differences for the values generated by the S550 and the reference values were within the calibration tolerance limits for the instrument, meaning the modified device provided reliable readings.
• Furthermore, the correlation coefficients for all values across each species examined were found to be excellent, suggesting a good reliability of the modified instrument.

Leukocyte Behavior and Size Distribution Histograms

• To better understand the behavior of leukocytes across different species, the researchers generated leukocyte size distribution histograms for all samples tested on the S550.
• The mean leukocyte volumes in diluent and lysing reagents for dogs, cats, horses, and cows were calculated and found to be 55.5, 56.6, 67.4, and 72.8 fl, respectively.
• The canine leukocyte counts were on average 14% less for 5 samples assessed on the unaltered instrument when compared to the results after increasing the leukocyte aperture current.
• The study pinpointed leukocyte threshold failures resulting in falsely high counts due to interfering particles, with 14%, 10%, 8% and 0% of the feline, bovine, canine, and equine samples respectively affected by this issue.
• The researchers concluded that errors relating to false-high leukocyte counts were generally not significant in dogs and cows, averaging a 5% deviation. However, the same issue caused an average 44% false-high leukocyte count for feline samples, making this a more relevant concern for cats.