What Does My Dog's Blood Test Mean? Is It Even Necessary?

During your dog’s annual vet visit, your veterinarian will likely do routine blood work on your pup. The first question a lot of pet parents ask themselves: “Is this test even worth it? Or are they just ripping me off?”

Short answer: It’s absolutely worth it!

Blood tests provide a wealth of information about your dog’s health. From immune status to blood clotting ability, anemia, diabetes, certain cancers, organ function, and the list goes on. They’re a valuable asset in your veterinarian’s toolbelt, as results can often provide the first clue that something’s not right (even when your dog appears otherwise healthy).

When Should a Dog Have Blood Tests?

The First Vet Visit. A new puppy should get baseline testing to evaluate health status and to screen for any underlying issues. Knowing what’s normal for your pooch makes it easier to identify when something suddenly changes.

Wellness Check-ups – Just like with us humans, dogs get routine blood work during their annual or semi-annual exam.

Senior Dogs – Since illness has a habit of sneaking up quietly, it’s suggested that aging dogs have routine blood screenings twice a year. This way, any changes are caught early. The sooner a problem is identified, the greater the chance of a positive outcome.

Prior To Surgery – Anesthesia is safe these days, but there are some things your vet will need to know before putting your pooch under. Blood tests help your doctor evaluate kidney and liver function, will alert him if your dog is anemic, dehydrated, has a blood clotting problem, is diabetic, etc. The more information your veterinarian has before administering anesthesia – the better.

According to VCAhospitals.com

“Blood tests will increase the chance of detecting a hidden problem that could prove to be life-threatening.”

Medical Conditions – If your pooch has any chronic medical issues like diabetes, thyroid, liver, kidney, etc., your veterinarian will want to do periodic blood work to make sure Fido’s condition is stable.

Medications – Some medications require periodic bloodwork to assess their effectiveness and to evaluate whether any adjustments are needed.

Blood Test Types

Complete Blood Count (CBC): This is one of the most commonly run blood tests. As the name implies, it’s a count of the body’s blood cells and an analysis of their shape and quality. Several components make up the CBC. Red Blood Cells, White Blood Cells, and Platelets. It’s a good indicator of overall health, can identify anemia, infections, and can even raise flags regarding some cancers.

Red Blood Cells (RBC’s) (AKA Erythrocytes) are the most numerous cells in the body. They are produced in the bone marrow and have a life span of approximately 120 days. Their primary function is to carry oxygen. The red blood cell count is the total number of RBC’s in a particular volume of blood.

Hemoglobin (HGB) are carrier molecules found inside the red blood cells. It’s the HGB that gives blood it’s red color. Its job is to transport oxygen. HGB carries oxygen to body tissues and organs, and transports carbon dioxide back to the lungs to be exhaled. If the body is low on HGB, less oxygen will be transported to the cells. This happens with anemia.

Hematocrit (HCT) is the percentage of RBC’s in a certain volume of whole blood. A low HCT may indicate anemia or bleeding. A high HCT may point to dehydration.

Platelets (AKA Thrombocytes) are cell fragments and they control bleeding. Platelets form clots to help prevent or stop bleeding. When platelets are low, there is a higher risk of bleeding.

White Blood Cells (WBC’s) (AKA Leukocytes): WBCs are a major part of the immune system. There are various types of WBCs and they all work in their own specialized ways to fight infection. Think of them as the body’s army. When they detect infectious invaders, the WBC’s increase in number so they can fight germs and defend against bacteria, viruses, fungi, etc,. Therefore, a high WBC count may indicate infection, whereas a low WBC may put you at risk for infection.

Blood Chemistries

The following tests are known as blood chemistries and are run using the liquid portion of the blood (AKA blood serum). These blood tests measure various substances in the blood that can help your veterinarian assess organ function and status.

Albumin (ALB) ALB is a vital protein produced in the liver. It transports various molecules around the body and helps regulate fluid balance by keeping fluid from leaking out of the blood vessels and into the body tissues. Serum Albumin testing can help provide the veterinarian with clues as to the liver, kidney, and nutritional health.
Alkaline Phosphatase (ALKP) This liver enzyme is found throughout the body, in the liver, bones, kidneys, and the intestines. Increased levels of ALKP could indicate liver damage, Cushing’s Disease, or rapid growth in young dogs.
Alanine Aminotransferase (ALT) ALT is a liver enzyme that’s found within the liver cells. When the liver becomes irritated or damaged, ALT enzymes are released into the bloodstream.
Amylase (AMYL) Increased levels could point to pancreatitis or kidney disease.
Aspartate Aminotransferase (AST) AST is found in the liver, skeletal muscle, and heart muscle. Increased levels could indicate damage to the liver, heart muscle, or skeletal muscle.
Blood Urea Nitrogen (BUN) evaluates kidney function and is normally tested along with a creatinine test to provide a clearer look at kidney function.
Calcium (Ca+) Elevations in calcium can have numerous causes. Certain cancers, kidney disease, parathyroid issues, and some toxicities. Decreases can be found when albumin levels are low and in some forms of parathyroid disease.
Cholesterol (CHOL) Elevated cholesterol in dogs is often seen in various metabolic disorders like diabetes mellitus, Cushing’s Disease, hypothyroidism, pancreatitis, and kidney disease. Decreases in cholesterol can be indicative of liver and intestinal diseases.
Chloride (Cl-) A decreased level of this electrolyte can be seen from vomiting or in Addison’s disease. High chloride levels may mean your pooch is dehydrated.
Cortisol (CORT) Cortisol is a steroid hormone produced by the adrenal glands. It’s the primary hormone at work in stressful situations and the body’s “fight or flight” response. Elevated levels can be indicative of Cushing’s Disease and decreased levels can point to Addison’s Disease. The test evaluates adrenal and pituitary gland function.
Creatinine (CREA) An elevated creatinine indicates that there is a problem with the kidneys. It doesn’t diagnose what that problem is, but it must be followed-up.
Gamma-Glutamyltransferase (GGT) This enzyme is found in several of the body organs, such as the liver, kidneys, pancreas, and small intestines. In the liver, it’s located in the cell membranes of the bile ducts and is a sensitive marker for liver and bile disease.
Globulin (GLOB) Globulin is a protein in the blood that is produced in the liver. Elevated results can be seen in conditions such as chronic inflammation, chronic infectious diseases, some tick-borne illnesses, allergies, some cancers, etc.
Glucose (GLUC) Glucose is the medical name for blood sugar. Increased glucose levels could indicate diabetes mellitus (DM). Insulin, which is produced in the pancreas regulates blood sugar. DM is a disease where the pancreas, for a variety of reasons, may not be able to meet the body’s insulin requirements to regulate blood sugar. Low levels of blood sugar could cause weakness, collapse, seizures, coma.
Potassium (K+) Potassium is an electrolyte in the body cells and bloodstream that can decrease from a fluid loss such as vomiting, diarrhea, excess urination, and various medications. Elevated levels of Potassium can indicate decreased kidney function, dehydration, Addison’s disease, and can cause a heart attack. In the body, K+ aids in the control of heart and brain function, nerve impulses, and muscle activity.
Lipase (LIP) This test is commonly used to detect disorders of the pancreas, ie., acute pancreatitis, chronic pancreatitis.
Sodium (Na+) This is an electrolyte that’s commonly lost along with fluid loss from vomiting or diarrhea, kidney disease, or Addison’s disease. Na+ is a good indicator of hydration status.
Phosphorous (PHOS) Increased levels of Phosphorous could be associated with kidney or thyroid disease, bone cancer, osteoporosis, or vitamin D toxicity.
Total Bilirubin (TBIL) This test can help identify liver or bile duct issues and some forms of anemia.
Total Protein (TP) The Total Protein can give clues to the hydration status of your dog as well as identifying liver, kidney, and infectious disease issues.
Thyroxine (T4) The primary hormone produced by the thyroid gland. Decreased levels may indicate hypothyroidism, while increased levels will point to hyperthyroidism.
Thyroid Stimulating Hormone (TSH) stimulates the thyroid to make more T4. So, high levels of TSH could be an indicator of hypothyroidism.

Blood Tests Often Run Together

Below are groups of some blood chemistries that are often used in conjunction with each other to form a more clear picture of your dog’s health status. Coordinating blood tests in this manner provides a non-invasive way to look at how well your pooch’s major organs are functioning.

Electrolytes

Electrolytes are electrically charged minerals that are carried in the liquid portion of the blood. Some have a positive charge, others negative, and keeping them in the proper balance is critical to your dog’s health. An electrolyte imbalance can quickly escalate into a medical emergency because electrolytes are at work in every cell of the body. Balance is crucial for proper nerve conduction, heart and muscle contractions, maintaining the pH of the blood as well as hydration status.

Sodium (Na+)
Potassium (K+)
Chloride (Cl-)

Kidneys

The most common tests that look at kidney function are the BUN and Creatinine.

Blood Urea Nitrogen (BUN)
Creatinine (CREA)
Phosphorous (PHOS)
Calcium (Ca)

Liver

The liver is the largest organ in a dog’s abdominal region. It aids in digestion, blood clotting, and filters wastes from the blood. The tests on this list are specific for measuring specific proteins and enzymes to evaluate liver function.

Alanine Aminotransferase (ALK)
Alkaline Phosphatase (ALKP)
Gamma-Glutamyltransferase (GGT)
Albumin (ALB)
Total Bilirubin (TBIL)

Pancreas

The pancreas is a gland located in the abdomen along the stomach and the first section of the small intestine. It produces enzymes that aid in digestion and hormones like insulin, that regulate blood sugar.

The tests below are commonly ordered to check the levels of specific pancreatic enzymes in the bloodstream which help assess pancreatic function. If your veterinarian suspects your pooch may have pancreatitis – these tests will be done.