CBC stands for “complete blood count”. But what is it and what does it mean? The CBC is one of the most important blood tests a veterinarian or physician can perform. The CBC determines various type of blood cells and their quantity. This number is extremely important in determining the health status of the patient being tested and sometimes the number can even diagnose a specific disease. Within the blood there are many different cells, which will briefly be mentioned: 1. RBC or red blood cells can indicate anemia, traumatic blood loss, dehydration, certain parasitic diseases, bone marrow status, etc. Hemoglobin is within the RBC’s in the blood. Its primary purpose is to carry oxygen throughout the body, and transport CO2 to the lungs to be expelled. 2. Platelets: are involved with the formation of blot clots. If the number is too low excessive bleeding can occur, if too high clots can form and obstruct blood vessels which can lead to a stroke, heart attack, or block blood flow to other parts of the body such as the lungs. 3. WBC or white blood cells. There are many different types and each have a specific meaning: a) Neutrophils: These are the most abundant type of WBC and form an essential part of the immune system. They are the first responders to infection, certain environmental exposures and some cancers. Generally, in bacterial infections their numbers increase and in viral disease their numbers decrease. b) Lymphocytes: the amount of this type of white blood cell is very helpful in diagnosing certain diseases like leukemia, lymphoma, infection after surgery, trauma, etc. They are very important cells that help fight off cancer and help control immune responses. There are 2 types of lymphocytes and they create antibodies for the immune system and fight off inf ection and cancer. c) Basophils: another white blood cell used to help diagnose certain cancers, allergic disorders parasitic disease, etc. d) Eosinophils: also fight off disease and elevate in allergic reactions. e) Monocytes: the last type of white blood cell that also fight off disease and aid in the immune system. These cells sometimes indicate a chronic state of inflammation, infection &/or immune response. This article is just a simple overview of the importance of the CBC test. It is used daily in all veterinary/medical practices.