Comparison of manual and automated methods for determining platelet counts in dogs with macrothrombocytopenia

Area of Science:

• Veterinary Hematology
• Canine Medicine

Background:

• Cavalier King Charles Spaniels (CKCS) are predisposed to macrothrombocytopenia.
• Accurate platelet counting is essential for diagnosing hematological disorders in dogs.

Purpose of the Study:

• To evaluate and compare various automated and manual methods for platelet counting in CKCS.
• To investigate platelet size variations in CKCS with different platelet counts.

Main Methods:

• Platelet counts were performed on 43 CKCS and 10 control dogs.
• Three automated systems and three manual methods (erythrocyte-lysing agents + counting chamber or blood smear evaluation) were utilized.
• Statistical analysis included correlation coefficients and significance testing.

Main Results:

• Good correlations (R2 = 0.71-0.85) were observed between all tested platelet counting methods (P < 0.0001).
• Manual methods demonstrated the highest correlation.
• Significantly larger platelets were identified in CKCS with platelet counts ≤ 100,000/microl compared to controls and CKCS with higher counts (P < 0.0001).
• Platelet counts were underestimated by most methods (except counting chambers) at levels ≤ 100,000/microl.

Conclusions:

• Manual platelet counting methods offer reliable results in CKCS.
• CKCS with low platelet counts exhibit significantly larger platelets, a key characteristic of macrothrombocytopenia.
• Careful method selection is necessary for accurate platelet quantification in CKCS, especially at lower counts.