Evaluation of equine hemograms using the ADVIA 120 as compared with an impedance counter and manual differential count.

The research compared an automated laser cell counter (ADVIA 120) with an impedance counter and manually conducted differential cell counts, in evaluating equine blood samples. The cell counters were used to measure various hematological parameters in the samples sourced from healthy horses.

Methodology

• The research was conducted using blood samples from 114 clinically healthy horses of varying breeds, both males and females, aged between 2 and 6 years.
• The blood samples were anticoagulated with EDTA and stored at 4°C for up to 12 hours before analysis.
• The blood samples were analyzed using two methods: ADVIA 120 and Hemat 8 impedance cell counter.
• In parallel, a manual differential leukocyte count was performed by three independent observers. These individual observers analyzed 100 to 200 cells in May-Grünwald-Giemsa-stained blood smears.
• The intra-assay precision of ADVIA 120 was measured by analyzing five replicates of ten of the blood samples.

Results

• The results showed that ADVIA 120 provided significantly higher readings than the impedance counter for red blood cell (RBC) count, total white blood cell (WBC) count, hemoglobin concentration, red cell distribution width, and mean corpuscular volume and hemoglobin concentration. In contrast, hematocrit and platelet count results were significantly lower on ADVIA 120.
• When comparing ADVIA 120 results with manual counts, the automated counter gave higher neutrophil and basophil counts but lower lymphocyte counts.
• Regression analysis showed that RBC and platelet counts were in good agreement between the two analyzers; however, other measurements displayed both constant and proportional biases.
• Coefficients of variation for erythrocyte parameters on the ADVIA were less than 1%, but were higher for platelet (6%), total WBC (2%), differential WBC (4%-30%), and reticulocyte (75%) counts.

Conclusions

• The results obtained from the ADVIA 120 were comparable to those from the impedance counter. Even though the reference intervals showed statistical differences, they overlapped.
• The ADVIA 120 showed poor precision for reticulocyte and differential leukocyte counts, which suggests manual verification of these counts might still be necessary.