Bloodwork Basics

The Basics of Bloodwork

Our veterinarians may order blood work for many reasons:

  • If your dog or cat is ill
  • If your pet will be undergoing anesthesia soon
  • If your pet is on certain medications
  • As part of a wellness or senior pet health screening

At Kalamazoo Animal Hospital, we have the ability to run some blood tests at the hospital while others are sent via courier to a large laboratory. Results from most blood tests sent to the laboratory are available within 24 hours. By utilizing both our in-house lab equipment and the larger referral lab facility, we are able to offer a wide range of tests and panels that help our veterinarians get a complete and accurate assessment of many aspects of your pet’s health.

Below, we’ve listed some of the most common tests we run and a basic explanation:

  • Heartworm & tickborne disease testing: For dogs, this is one of the most important tests we offer. This test is performed annually. We will test your dog for heartworm disease infection plus exposure to three tickborne diseases that are a concern in our area: Lyme disease, Anaplasma, and Ehrlichia.
  • Feline leukemia (FeLV) & Feline Immunodeficiency Virus (FIV) testing: Cats are susceptible to these two diseases that compromise their immune systems and can lead to secondary problems like oral disease, infections, and certain cancers. We recommend this combination test for all kittens and any newly adopted cats that have not already been tested. Cats that go outdoors regularly or have been bitten by another cat should also be tested to ensure that they have not been exposed to these viruses. If your cat tests positive for either of these viruses, there is supportive care available to help your cat live comfortably with the disease.
  • Complete Blood Count: For both dogs and cats, this test counts and analyzes the cells of your pet’s blood to screen for things like anemia, response to infection or inflammation, dehydration, and presence of the cells that help blood form clots. The basic cells that this test evaluates are:
    • Red blood cells: These are what carry oxygen throughout the body. If there are too few of these cells, your pet is anemic. If there are too many, your pet is polycythemic. The amount of these cells are also compared, as a percentage, to the amount of liquid in the blood. If the percentage of cells to liquid is higher than normal, your pet is likely dehydrated.
      • Fun fact: Greyhounds naturally have a higher level of red blood cells than other dog breeds.
    • White blood cells: White cells are responsible for fighting infection and inflammation. By analyzing what type of white blood cells are present and in what amounts, our veterinarians can gain valuable information. Increases or decreases can suggest certain diseases.
    • Platelets: If your pet is cut, platelets rush to the scene of the crime to stop the bleeding. They do this by sticking together and forming a plug. If your pet has too few platelets, they may not be able to form blood clots if they’re injured or they may bruise from even the slightest bump. On the other hand, if there are too many platelets, your pet may develop too many clots.
  • Serum Chemistries: These tests evaluate the function of various organs and systems within your pet. We’ve included the tests we perform most often, though there are several other less common tests that we can use to get even more information about a particular organ. We have also grouped the tests by the most common organ or body system we use them to evaluate. This is a simplified version of how these tests all play a part to show the veterinarian the larger picture of what’s going on inside your pet. If your dog or cat ever shows any labwork abnormalities, rest assured that our veterinarians will help you understand your pet’s individual results.
    • Serum Protein Levels: These levels aren’t evaluating dietary protein so much as evaluating if your pet is adequately making and keeping enough protein molecules within their blood stream. If serum protein levels are too low, for example, your pet may begin to leak fluid from the blood vessels into other spaces such as the abdomen or even the limbs; this is called edema. An elevated protein level can indicate dehydration. The two most prevalent serum proteins are albumin (ALB) and globulins (GLOB), so we often measure those individually, as well as evaluating an overall protein number called (unsurprisingly) total protein (TP).  
    • Electrolytes: Electrolyte levels are important indicators of kidney and urinary function and adrenal function. We can also see electrolyte changes if your pet is vomiting or having diarrhea frequently or is dehydrated or overhydrated. The three electrolyte values we routinely monitor are: potassium (K+), sodium (Na+), and chloride (Cl-).
    • Kidney values: Kidney disease can cause havoc throughout a pet’s bloodwork, resulting in findings like anemia, electrolyte changes, and more. When it comes to evaluating kidney function, the three most crucial values we’re looking at, however, are blood urea nitrogen (BUN), creatinine (CREA), and phosphorous (PHOS). Though dehydration and muscle condition can affect these values, in general, we begin to see increases in BUN and CREA when more than 75% of normal kidney function has been lost. Chronic kidney disease can cause an increase in phosphorous levels.
    • Liver values: The liver is important for so many things within the body: production of proteins and blood clotting factors, filtering out toxins, and more. In fact, one of our licensed veterinary technicians had a tech school professor who her class if they were ever unsure of a test answer, they should write down, “Liver.” It does that much! Like the kidneys, if the liver is struggling, we may see all sorts of changes in the bloodwork. If we’re evaluating liver function, we tend to zero in on these values first:
      • Alkaline phosphatase (ALKP): If this value is elevated, it may indicate liver damage or “stress” on the liver from corticosteroids (either those produced naturally by the body or from medication being administered to the pet, such as prednisone). It is routinely mildly elevated in puppies and kittens due to bone growth.
      • Alanine aminotransferase (ALT): Elevations are often due to active liver damage.
      • Gamma-glutamyl transferase (GGT): Elevations can indicate liver disease or gall bladder disease.
      • Total bilirubin (TBIL): This is the substance that causes jaundice. If it is elevated, it may indicate bile duct malfunction or liver disease. It can also be an indicator that red blood cells are being destroyed within the body.
    • Other: These are some other miscellaneous values that are often important:
      • Thyroxine (T4): This is a thyroid value that is especially important for cats. Many cats become hyperthyroid (over produce thyroid hormones) as they age; an elevated T4 is diagnostic for feline hyperthyroidism. T4 in dogs can also point is in the direction of hypothyroidism (underproduction of thyroid hormones), although it is not diagnostic alone.
      • Glucose (GLU): Glucose is the substance we’re measuring when we check blood sugar. If the glucose is too high, it may indicate that a pet is diabetic. If it is too low, the pet may be disoriented or even have a seizure.
      • Amylase (AMYL) and Lipase (LIP): Both of these substances correlate to pancreatic function. Elevations may indicate pancreatitis (inflammation or infection of the pancreas).
      • Calcium (Ca): This value can increase or decrease due to certain cancers, endocrine disorders such as hyperparathyroidism, kidney disease, and serum protein level changes. If calcium levels are chronically elevated, they can begin to cause other problems within the body, such as kidney dysfunction. 

As you can see, we get tremendous amounts of information from analyzing your pet’s blood.  Sometimes, when the diagnosis isn’t straightforward, bloodwork can make all the difference in ensuring your pet gets the treatment he or she needs in a timely fashion. Other times, routinely monitoring bloodwork at a pet’s annual or senior visit can help us catch a problem early. Bloodwork is one of the most important tools our veterinarians have to give the best possible care to our patients.