NAVLE – Veterinary Licensing Exam

Classify anemia by regeneration first. In dogs and cats, an absolute reticulocyte count above about 60,000/µL (dog) or 50,000/µL (cat, aggregate reticulocytes) indicates regeneration, which takes 3–5 days to appear after acute blood loss or hemolysis. Regenerative anemia means blood loss or hemolysis; nonregenerative anemia means a marrow problem or chronic disease (anemia of inflammation, chronic kidney disease, FeLV, marrow failure). Count only aggregate reticulocytes in cats; punctate forms reflect older regeneration.

In horses and ruminants, fibrinogen (heat precipitation) rises with inflammation even when the white cell count is normal, and serum amyloid A is a sensitive acute-phase protein in horses. For coagulation, the PT tests the extrinsic and common pathways and lengthens first in anticoagulant rodenticide toxicosis because factor VII has the shortest half-life. The aPTT (or ACT) tests the intrinsic and common pathways and is prolonged in hemophilia A and B. Buccal mucosal bleeding time tests primary hemostasis when the platelet count is normal (von Willebrand disease, NSAID effect). Spontaneous bleeding from thrombocytopenia is unusual until platelets fall below about 30,000–50,000/µL. On a blood smear, each platelet per oil-immersion field represents roughly 15,000–20,000/µL.

Fine-needle aspirate cytology first separates inflammation from neoplasia, then classifies tumors by cell type. Three or more nuclear criteria of malignancy (anisokaryosis, high or variable N:C ratio, multiple or prominent nucleoli, coarse chromatin, mitotic figures) support a malignant diagnosis. Histopathology remains the standard for grading and margins. A non-aspiration (fenestration) technique reduces blood contamination from vascular organs such as spleen and liver, and impression smears or ear swab cytology quickly identify yeast (Malassezia), cocci and rods in otitis and pyoderma.