What is a complete blood count (CBC)?
A complete blood count (CBC) is a laboratory test that measures the types and quantities of cells in an animal's blood, including red blood cells, white blood cells, and platelets.
A CBC is one of the most common blood tests ordered by veterinarians and provides a snapshot of an animal's blood health. The test measures three main cell populations: red blood cells (which carry oxygen), white blood cells (which fight infection and support immune function), and platelets (which help with blood clotting).
The test also measures hemoglobin and hematocrit levels, which indicate how much oxygen-carrying capacity the blood has. Results help a veterinarian diagnose several conditions:
- High white blood cell counts often signal infection, inflammation, or bone marrow disease
- Low red blood cell counts indicate anemia, which can result from blood loss, nutritional deficiency, or chronic disease
- Low platelet counts may suggest bleeding disorders or certain systemic illnesses
- Abnormal cell appearance can point to leukemia or other malignancies
Veterinarians typically order a CBC when an animal shows symptoms like lethargy, loss of appetite, or pale gums, or as part of routine wellness screening. A general practice veterinarian will interpret CBC results alongside physical examination findings and clinical signs to guide treatment decisions.