A physical examination can tell us a lot about your pet, but additional blood tests give us a more complete health picture. Our Smithtown Animal Hospital team commonly recommends blood work for sick and healthy pets, so we want pet owners to understand more about this basic test. Here is an overview explaining the reasons why we may order blood work, how we interpret results, and what your pet’s blood work can and cannot tell us.

Common reasons to run blood work on your pet

Blood tests provide valuable information about your pet’s internal organ function, hydration status, blood cell function, and more. We may order these tests to:

  • Diagnose a sick pet
  • Monitor pets taking long-term medications
  • Establish a baseline for young, healthy pets
  • Determine a pet’s health before anesthesia or surgery
  • Detect disease early through adult and senior wellness testing

Pet blood work components

If you look through our reference lab catalog, you’ll see that we can run hundreds of specialized tests on your pet’s blood. The term “blood work” typically refers to only a basic blood panel, which has several standardized components that we can analyze in-house or send to an outside lab. These standard blood tests typically include:

  • Chemistry panel — This panel checks for proteins, fats, enzymes, and other substances in the liquid blood portion related to metabolism, immune health, and organ function.
  • Complete blood count (CBC) — A CBC examines the blood cell component, determining red and white blood cell and platelet numbers, types, and appearance.
  • Thyroid screening — Thyroid hormone levels are often, but not always, included in basic blood panels, depending on the individual pet and their situation. 

Other commonly recommended blood tests include heartworm and tick-borne disease testing for dogs, and viral testing, including feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV), for cats. We usually order these tests during a wellness visit either alone or in combination with other basic blood tests.

Pet blood work interpretation and value

Each blood work component provides different information about your pet’s health, which our team interprets as a whole. Veterinarians receive extensive training in understanding the meaning of changes in each blood test value, and how different result patterns can indicate certain, specific diseases. Depending on the underlying issue, blood work can definitively diagnose a problem or lead us to suspect a certain problem that requires additional tests for more information.

Together, your pet’s chemistry and CBC panel, sometimes combined with a urinalysis, can help us determine the following:

  • Kidney function
  • Liver function
  • Pancreatic function
  • Blood cholesterol levels
  • Infection presence
  • Inflammation presence
  • Immune function
  • Oxygen carrying capacity
  • Clotting ability
  • Anemia (i.e., low red cell count)
  • Electrolyte, mineral, and acid-base balance

Pet blood work limitations

While blood work is extremely helpful in diagnosing many problems and monitoring overall health, chemistry and CBC are not all-knowing. Owners frequently ask whether blood tests can show that their pet has cancer. Unfortunately, a cancer diagnosis is beyond a blood test’s capabilities, although several highly specialized blood tests can detect cancer presence in certain situations. A complete blood count may provide clues about lymphoma or leukemia, but other cancer types typically do not cause obvious changes to blood work. A cancer diagnosis usually involves biopsies, X-rays, and abdominal ultrasound.

Blood work also cannot provide information about heart function. Testing for heart problems includes an EKG to examine heart rhythm and electrical activity, echocardiogram (i.e., heart ultrasound) to observe the heart and heart valves in action, and X-rays to look at overall heart size and shape.

Basic blood work can provide clues about common adrenal problems, other endocrine disorders, auto-immune diseases, toxicities, or infectious diseases, but additional tests are typically required to diagnose these conditions.

Common problems found on pet blood work

Blood work can help us diagnose new or chronic diseases, or identify immediate issues in your pet that require prompt treatment and correction. Frequent blood work changes that we see and the problems they indicate include:

  • Elevated BUN and/or creatinine — Indicate kidney injury, disease, or dehydration
  • High blood sugar — Stress or diabetes
  • High or low thyroid hormones — Hyperthyroidism or hypothyroidism
  • Decreased blood fluids or altered electrolytes — Dehydration
  • Elevated liver enzymes — A liver, endocrine, gastrointestinal, or drug toxicity problem
  • Increased pancreatic enzymes — Pancreatic inflammation
  • Altered white blood cell balance — Infection, stress, or inflammation
  • Low red blood cells — Infection, kidney disease, blood loss, or auto-immune disease
  • Low platelets — Infection, bleeding, or auto-immune disease

The next time our Smithtown Animal Hospital team recommends blood work for your pet, you’ll be more prepared to understand why, and how, our veterinary team interprets blood test results. Contact us to schedule a visit or blood test if your pet is feeling unwell, is due for their wellness visit, or needs pre-anesthetic testing for an upcoming surgery or dental procedure.