Quantitative buffy coat analysis for hematologic measurements of canine, feline, and equine blood samples and for detection of microfilaremia in dogs

A quantitative buffy coat (QBC) analysis was evaluated for 175 canine, 125 feline, and 125 equine blood samples. The method used centrifuged whole blood and yielded rapid results expressed as respective band lengths for RBC, granulocytes, nongranulocytes, and platelets. Simple regression analysis of band lengths and reference laboratory methods yielded correlation coefficients (r) ranging from 0.72 to 0.99. The PCV, granulocyte count, and total WBC count, as determined by the 2 methods, correlated well (r greater than or equal to 0.93 in all cases). Platelet and nongranulocyte counts were less well correlated. The QBC system provided a means of performing rapid hematologic screening. The principal problem encountered was poor separation of the RBC-granulocyte interface in 17% of canine samples, which interfered with measurement of band lengths. Evaluation of the QBC tube for detection of Dirofilaria immitis microfilaremia revealed 100% sensitivity to counts as low as 160 microfilariae/ml of whole blood.