Neutrophils possess a densely-stained, clumped nucleus that develops more segments as it ages. The cytoplasm is clear to pale blue/grey with many small light pink granules. Also referred to as a polymorphonuclear leukocyte.

Neutrophils possess a densely-stained, clumped nucleus that develops more segments as it ages. The cytoplasm is clear to pale blue/grey with many small light pink granules. Also referred to as a polymorphonuclear leukocyte. Monocytes are the largest of all leukocytes. It possesses a pleomorphic nucleus with fine, lacy chromatin that stains lighter than other leukocytes. There is abundant blue-grey cytoplasm which appears "foamy" and often contains vacuoles (bubbles).

Lymphocytes are most commonly seen in their smaller form in cats, but can also be medium to large in size. It has a high nucleus:cytoplasm ratio. The nucleus is round (free of segments) with coarse chromatin clumping. The cytoplasm is blue and often scant.

Lymphocytes are most commonly seen in their smaller form in cats, but can also be medium to large in size. It has a high nucleus:cytoplasm ratio. The nucleus is round (free of segments) with coarse chromatin clumping. The cytoplasm is blue and often scant.

Eosinophils are similar in size to the neutrophil. The nucleus is often band-shaped or limited to two or three lobes. The chromatin is clumped and stains dark, as in the neutrophil. The cytoplasm is light blue but is often obscured due to the presence of numerous medium-sized eosinophilic granules that stain orange-pink. In cats, the granules are rod shaped.

Eosinophils are similar in size to the neutrophil. The nucleus is often band-shaped or limited to two or three lobes. The chromatin is clumped and stains dark, as in the neutrophil. The cytoplasm is light blue but is often obscured due to the presence of numerous medium-sized eosinophilic granules that stain orange-pink. In cats, the granules are rod shaped.

Basophils are rarely encountered in mammals. They are similar in size to the neutrophil with a similar looking nucleus. The nucleus can sometimes be obscured by numerous basophilic granules that stain light or dark purple to almost black. Typically, the granules are lighter staining in cats and dogs, and darker staining in ruminants and horses.

A common finding in cats, megathrombocytes are platelets that are larger in size. They are equal to, or greater in size than an RBC.

A result due to a delay in adding freshly collected blood into an anticoagulant. Cats are more prone to platelet clumping. Screening for clumping should be performed in the feathered edge of the monolayer.