Complete Blood Count (CBC)

This is a common test performed on horses to provide objective information about the general health status of an animal. The objective data obtained from a CBC can be helpful in monitoring ill patients undergoing therapy; therefore, serial CBC requests are common.

• RBC (Red blood cell count) - total red blood cell count. Too low means anemia, too high means erythrocytosis or dehydration.

• HCT (Hematocrit) – measures percentage of red blood cells in whole blood, also called “packed cell volume (PCV).

• HGB (Hemoglobin) – measures the oxygen carrying ability of the RBC.

• MCV (Mean cell volume) MCH (Mean cell hemoglobin) MCHC (Mean cell hemoglobin concentration) – calculated values that correlate the amount of hemoglobin and the size of the RBC.

• RDW (Red cell distribution width) – increases in this objective measure indicates increased variability in size that can aid the veterinarian in identifying the cause of a RBC problem.

• WBC (White blood cell count) – provides an overall number of all types of WBC’s – neutrophils, lymphocytes, monocytes, eosinophils and basophils. They play a role in inflammation and fighting infection.

• NEU (Neutrophil) – these cells typically make up about 2/3 of the total WBC count. Count may increase with inflammation, infection or stress.

• LYM (Lymphocyte) – usually make up about 1/3 of the total WBC count. If your horse was stressed at the time of blood collection (recent excitement or exercise) this may decrease the count.

• MONO (Monocyte), EOS (Eosinophil), BASO (Basophil) – Typically very low percentage on the differential, elevations can indicate certain inflammatory conditions such as allergies or parasitism.

• PLT (Platelet) and PCT (Platelet crit) – a component of the blood clotting system. Diseases can indicate impaired clotting ability.

• MPV (Mean platelet volume) – increases indicate presence of larger than normal platelets commonly associated with response to need for platelets.

• PDW (Platelet distribution width) – increases in this objective measure of variablility of platelet size indicates increased variability in size which may be an indicator of response to a need for platelets; decreases may be seen with immune-mediated thrombocytopenia.

• FIB (Fibrinogen) – Functions in blood coagulation and to contain inflammatory conditions. Increases indicate inflammation and decreases can indicate disseminated intravascular coagulation, liver failure and major surgery.