Evaluation of the Mythic 18 hematology analyzer for use with canine, feline, and equine samples.

The research investigated the effectiveness of the Mythic 18 hematology analyzer in assessing blood samples from dogs, cats, and horses. The study examined its accuracy, precision, linearity, carry-over, stability, and usability.

Research Methodology

• The researchers used the Mythic 18 analyzer to examine ethylenediamine tetra-acetic acid-blood samples from 122 dogs, 140 cats, and 123 horses.
• The results from the Mythic 18 were then compared with reference methods, which included Sysmex XT-2000iV, manual hematocrit, and microscopic WBC differentiation.
• To check the agreement between the results, the team performed Pearson’s coefficient of correlation, Passing-Bablok regression analysis, and Bland-Altman difference plots.
• To find out the precision of the Mythic 18, they calculated the standard deviation and coefficients of variation.
• The linearity of the instrument was determined according to the Emancipator-Kroll method.

Key Findings

• Red blood cell parameters from the Mythic 18 correlated excellently with the reference methods, with only two exceptions: red cell distribution width and mean corpuscular hemoglobin concentration.
• The total WBC count correlated excellently in canine and equine samples and very well in feline samples. However, the study noted that the Mythic 18 overestimated WBC in 23 feline samples that had platelet aggregates.
• The absolute granulocyte counts from the Mythic 18 correlated excellently for all three tested species.
• The instrument showed a good correlation for equine lymphocyte counts. However, the correlation for canine and feline lymphocyte counts was poor.
• Feline platelet counts recorded a good correlation with a negative bias.
• The overall precision of the Mythic 18 ranged from good to excellent.
• The accuracy of the full 3-part differential was confirmed in horse samples. In dogs and cats, the granulocyte counts were found to be reliable.
• Despite the generally positive results, the researchers recommend evaluation of a blood smear to verify WBC differentiation and to identify potential abnormalities, considering the limitations inherent to impedance-based hematological instruments.