When a veterinarian orders blood work for a pet, it's usually because the animal's feeling under the weather or has reached an age where it's time to get some baseline values. There's a bunch of information in those numbers. Though it may seem like a foreign language, you don't need a medical degree to interpret your dog's blood panel results.
Basic Blood Panel Terms
Your dog's blood is comprised of liquid and blood cells. When the vet takes a blood sample from your dog, his blood is broken apart and examined for a host of different values that provide a wealth of information about his organ function and overall health. The complete blood count focuses on his blood cells and measures the different types of red blood cells and white blood cells, as well as platelets and hemoglobin. There's also a chemistry panel, which measures what's left in the remaining liquid after the blood cells are removed -- the serum.
Normal is Relative
Blood panel values have normal ranges for dogs and cats, though what's considered normal can be relative. A healthy young dog's values likely will be different from a healthy senior dog's values. As well, many things can influence a specific value, such as whether a dog has had sufficient water, medication, stress or what or when he ate prior to his blood work.
Complete Blood Count
There are more than a dozen values in the hematology portion of a blood panel. In addition to red blood cells and white blood cells, the complete blood count tallies platelets, responsible for clotting, as well as packed cell volume, representing the percent of blood cells compared to total volume of blood. Hemoglobin is the part of a red blood cell carrying oxygen. The white blood cell count includes values for different types of white blood cells, including eosinophils, neutrophils, basophils, monocytes and lymphocytes.
Generally, a normal red blood cell count for a dog is between 5.5 and 8.5 x 100,000/L, and a normal white blood cell count ranges between 6.0 and 17 x 1,000/L. A normal packed cell volume is between 37 and 55 percent. A higher than normal red blood cell count is often indicative of dehydration; low platelets may reflect bone marrow damage. High levels of lymphocytes and neutrophils often indicate infection, while low neutrophils can indicate viral illness or bone marrow disease. Higher basophils and eosinophils may point to parasitic infection or allergies.
Blood Chemistry Panel
Blood serum carries a wealth of information providing a snapshot of organ health. Kidney function is reflected in blood urea nitrogen and creatinine; alkaline phosphatase, albumin, cholesterol, gamma-glutamyl transpeptidase, globulin, serum glutamate pyruvate transaminase, total bilirubin and total protein provide information about liver health; amylase and lipase are indicators about pancreatic health; and thyroid health is measured by T3 or triiodothyronine and T4 or thyroxine. Each item has its own range of what's considered normal. As a dog ages, it's common for certain levels to change, as his organs function differently with time.
Putting it All Together
It's easy to see a low or high number and become worried about your dog's health. For your sake -- and your dog's sake -- don't panic if something is out of line on your dog's blood panel results. Given the variety of factors potentially influencing the results, it's not unusual to get a different reading if a new sample is taken, even a day later. Your vet will decide to test again, if necessary, as well as consider all of the values, your dog's current condition, his age, his breed and his medical history when interpreting the results of his blood panel.