June 2, 2014
When your veterinarian recommends running routine bloodwork, it can be a mystifying process. Here we will try to unravel the mysteries of your pet’s bloodwork and help you understand how to interpret the basics.
The most common bloodwork that your veterinarian is likely to run as routine screening tests is a “CBC/Chem”. CBC stands for Complete Blood Count and Chem stands for Chemistry. A CBC will analyze the red and white blood cell counts as well as platelets in the blood stream.
A low red cell count is a sign of anemia, while a high red cell count can be a sign of dehydration or other more rare disorders. The white blood cell count is an indication of your pet’s immune system. It’s an evaluation of the total white cell count as well as different types of white cells involved in the immune response. An elevated white cell count can indicate an infection, or sometimes it can indicate cancer. A low white cell count is a sign of immune suppression.
A CBC will also evaluate the platelet count. If the platelets are too low, your pet can be prone to bleeding. If they are too high, it can be a sign of cancer or in some cases can be a variant of normal.
A chemistry profile will evaluate all major organ systems in the body, including liver, kidney, pancreas, electrolytes and protein levels. Liver enzymes include ALT, AlkPhos and GGT. When liver enzymes are elevated it can indicate toxicity, infection, recent trauma, Cushing’s disease, cancer or other causes. It’s important to remember that elevated liver enzymes do not necessarily indicate poor liver function. It just indicates the liver had an insult.
To evaluate liver function, you need a special blood test called Bile Acids and often you also need an abdominal ultrasound or biopsy to understand why liver enzymes are elevated.
BUN and Creatinine
Kidney function is evaluated with BUN (Blood Urea Nitrogen) and Creatinine. The BUN is a by-product of protein breakdown and can be elevated normally in pets eating high protein diets and can also be normal in the Greyhound breed. When both BUN and Creatinine are elevated, we worry the kidneys are not functioning well. It takes 75% loss of normal kidney function before we see elevations in the BUN/Creat, therefore elevations in bloodwork indicate the kidneys are functioning only at 25% or less than normal capacity. Urine tests are used to further evaluate kidney function.
Amylase and Lipase
The enzymes Amylase and Lipase evaluate function of the pancreas, a major digestive organ. When both amylase and lipase are elevated, we worry about potential pancreatitis. This can be a difficult digestive illness to manage, which can often require hospitalization and life-long restriction in fat in the diet. A more definitive test called a PLI (pancreatic lipase immunoreactivity) and abdominal ultrasound may be recommended to further assess the function of the pancreas.
How Ofter To Run Bloodwork?
As a general preventative measure, blood work should be run annually on all pets and bi-annually in pets over 6-8 years of age. This will allow your veterinarian to pick up on early signs of diseases before they become more problematic. In certain regional areas, other tests such as a heartworm test and tick titers may also be indicated to screen on a regular basis.
Finally, if any part of your pet’s bloodwork doesn’t make sense, just ask your veterinarian to explain in simple terms and they will be happy to unravel the mystery.
Please note: It's important to remember that only your veterinarian should interpret bloodwork results as certain breeds can fall outside the laboratory normal reference range and even some individual pets can be quite normal even if they fall slightly outside of this "range". All results need to be interpreted within the context of your pet's age, breed, sex and symptoms they may be experiencing.