Understanding Blood Work: The Complete Blood Count (CBC) for Dogs
Overview of the Complete Blood Count (CBC) for Dogs
Blood work is a very important diagnostic tool that provides vital information about your pet’s health. A complete blood count (CBC) is a common blood test used in dogs to measure and evaluate cells that circulate in the blood. The test includes an actual counting of red and white blood cells as well as an analysis of cells viewed on a blood smear. A CBC may be useful as a screening test for underlying infection, anemia and illness.
Sometimes, the CBC can help determine the underlying cause of an anemia or infection. Drugs that affect the bone marrow change the CBC. Certain types of cancers, especially leukemia, may be evident on a blood smear. Blood parasites and some microorganisms are found by careful inspection of the blood cells during the CBC. In some cases, the results of the CBC will prompt your veterinarian to recommend other diagnostic tests.
Sample CBC in Dogs
The following is an example of a complete blood count report. Normal values often vary from lab to lab and are represented in parentheses. These norms should not be considered universal.
WBC….. 10.6 x 10-3/mcl………(4-12 x 10-3/mcl)
RBC……. 6.2 x 10-6/mcl……..(5.7-10.5 x 10-6/mcl)
HGB…….. 14 g/dl…………(9-16 g/dl)
MCV……. 55.9 fl…………(40-60 fl)
MCH……. 18.2 pg…………(15-20 pg)
MCHC…… 33.5 g/dl……….(32-36 g/dl)
What Does the CBC Mean in Dogs?
WBC is an abbreviation for white blood cell count. These cells help fight infection and respond when an area of the body becomes inflamed. Elevated white blood cell counts indicate infection, inflammation and some forms of cancer or leukemia. Low white blood cells counts can indicate viral infections, bone marrow abnormalities or overwhelming infections and sepsis (blood poisoning). In this situation, the white blood cells are concentrated in the area of infection and are not circulating in the blood, resulting in a low count.
RBC is an abbreviation for red blood cell count. These cells are responsible for transporting oxygen throughout the body. Oxygen is used as fuel for the body and is very important. High red blood cell numbers usually indicate dehydration but can also indicate uncommon diseases that cause an excess production of red blood cells from the bone marrow. Low red blood cell counts are referred to as anemia and can be a result of blood loss, active bleeding, bone marrow disease or excessive red blood cell breakdown that is seen in some immune diseases and toxin ingestion.
HGB is an abbreviation for hemoglobin. This molecule is responsible for binding and releasing oxygen onto the red blood cells. Without hemoglobin, oxygen cannot be transported. High levels of hemoglobin usually indicate high red blood cell counts and dehydration. Low levels indicate anemia, bleeding or iron deficiency.
HCT is an abbreviation for hematocrit. The hematocrit is a calculated percentage of red blood cells in the circulation. It gives similar information to the red blood cell count but the value is expressed as a percentage. The other part of the blood is serum, containing enzymes, proteins, electrolytes, etc. High hematocrits indicate dehydration or rare bone marrow disorders resulting in increased red blood cell production. Low hematocrits indicate anemia, bone marrow disorders, blood loss, active bleeding or excessive red blood destruction due to toxins or immune disorders.
MCV is an abbreviation for mean corpuscular volume. This is the average size of the red blood cells. A high MCV usually indicated certain vitamin deficiencies. A low MCV indicated iron deficiency.
MCH is an abbreviation for mean corpuscular hemoglobin. This is the average weight of hemoglobin in each red blood cell and is different than hemoglobin circulating in the blood. A high MCH indicates poorly oxygenated blood. A low MCH indicates iron deficiency.
MCHC is an abbreviation for mean corpuscular hemoglobin concentration. This is the average percentage of hemoglobin in each red blood cell. A high MCHC indicates that there is too much hemoglobin in the red blood cell, indicating a high iron level since an important component of hemoglobin is iron. Iron excess is just as damaging to the body as iron deficiency. A low MCHC indicates anemia.
PLT is an abbreviation for platelets. The platelets are responsible for sealing any leaks in the blood vessels. When platelet counts are low, spontaneous bleeding can occur. High platelet counts usually indicate a disorder of the bone marrow or an overwhelming response to an immune blood disease. Low platelet counts indicate bleeding or excessive destruction of platelets caused by parasites or immune diseases.