Understanding Dog Blood Test Results

Blood tests are routinely used by veterinarians to monitor a dog’s health or help diagnose medical conditions. But often the results of a dog blood test, or the reasons why a test is being run in the first place, can be confusing for pet parents to understand, so let’s try and clear things up for you. 

In this article, you will learn why dogs need blood tests, the most common types of blood tests in dogs, how to understand blood test results, and how much testing generally costs. 

Why Do Dogs Need Blood Tests?

Veterinarians can gain a wealth of information about the health of a dog by running different blood tests. 

At your dog’s last annual examination, your veterinarian may have recommended running routine bloodwork to check the health of blood cells and internal organ function. The reason for this is even though a dog may look and act healthy on the outside, they may have hidden problems “under the hood.” Testing allows veterinarians to detect problems early when they are small and intervene to stop or slow the progression of disease. Having your dog’s blood tested annually can also help your veterinarian track health trends over time and know what is “healthy” for your dog if they ever get sick. 

Another reason your veterinarian will recommend or require routine bloodwork is if your dog is receiving certain medications over a long period of time or about to start a new medication. For example, if your dog is regularly receiving a non-steroidal anti-inflammatory drug (NSAID) like carprofen, your vet may require bloodwork before refilling the medication. Bloodwork for medication varies but usually checks liver and kidney function and sometimes levels of medication in the blood. If you want to purchase heartworm prevention for your dog, your vet will run a heartworm test before they prescribe the medication. 

Lastly, if your dog is going to be anesthetized for any reason, a veterinarian will often run routine blood tests to ensure that the dog is healthy enough for anesthesia. 

In addition to routine bloodwork, a veterinarian will run blood tests if your dog is sick. Routine bloodwork can provide information about many diseases and conditions, including:

• Anemia
• Blood parasites
• Liver disease
• Kidney disease
• Protein losing diseases
• Inflammation
• Infection
• Auto-immune disease
• Dehydration
• Cancer

Types of Dog Blood Tests

Routine bloodwork typically consists of a few tests that can usually be run in-hospital for same-day results:

• Blood chemistry checks internal organ function, body electrolyte and fluid balance, blood proteins, blood sugar, minerals, and some enzymes
• Complete blood count, otherwise known as CBC blood test for dogs, checks red blood cells, white blood cells, and platelets
• Heartworm antigen test checks for the presence of heartworm disease
• 4DX blood test for dogs checks for four infectious diseases (heartworm disease, Lyme disease, ehrlichiosis, and anaplasmosis) carried by external parasites.

Additional blood tests that are not included in routine bloodwork can be run to further classify and diagnose a dog’s problem. There are many specialized blood tests for dogs available. Some tests can be run in-hospital for same-day results. Other tests must be run in a reference laboratory. Results for tests that are run at a reference laboratory take longer because the blood sample must be sent to the laboratory. Some of the more common specialized blood tests used by veterinarians include:

• T4, Free T4 by dialysis, and T3 – used to diagnose thyroid problems
• ACTH and low-dose-dexamethasone testing – used to diagnose Cushing’s syndrome
• Serological testing – used to determine vaccination/protection status of a dog against specific infectious diseases
• B-type natriuretic peptide (BNP) – checks a hormone that is released by heart muscles when they are stressed, used to monitor heart disease
• Spec cPL Test/Spec fPL Test – checks a hormone that is released by the pancreas when it is inflamed, used to diagnose pancreatitis
• Nu.Q Cancer Test – tests for seven common cancers found in dogs
• SDMA test for early detection of kidney disease
• Allergy testing
• DNA testing

Understanding Blood Test Results for Dogs

Trying to interpret dog blood test results can feel like trying to understand ancient Greek if you don’t know what you are looking for. While any and all blood tests for your dog should be interpreted with the guidance of a veterinarian, it can be helpful to at least understand the basics of blood test results. 

First, let’s talk about blood tests that result in a numerical value. For every blood test that results in a number, there is a reference range that has been previously established as “normal.” The reference range is the result of testing many healthy dogs and averaging the results. Reference ranges are provided by the laboratory and do not vary based on individual dogs. 

For example, the normal reference range for blood glucose (sugar) in dogs is 80-120 milligrams/deciliter (mg/dl) of blood. If your dog’s blood sugar falls within this range, they are considered to have normal blood sugar. Blood values that fall within their reference range and are “normal” will usually show up as green on printed lab work. If a dog’s blood sugar is outside this range and is either too high or too low, then the result will be flagged with a red color, alerting the veterinarian that something isn’t right.

Interpreting blood test results isn’t as straightforward as it seems, however. A completely normal dog may have high blood sugar levels because they just ate. A dog may have low thyroid hormone levels because they are sick with something else, not because they are hypothyroid. Dehydration causes concentration of red blood cells in the blood, and blood tests on a dehydrated, anemic dog may come back with “normal” levels of red blood cells, even though the dog is clearly very sick. This is why it is very important for veterinarians to interpret blood test results in light of the dog’s overall condition and take into account anything that can affect test results. 

Specialized testing, especially tests that are run in reference laboratories, will not only give a numerical result but also will provide additional context on how to interpret the results. Furthermore, if a veterinarian does not understand the results, they can call the laboratory to get more information. 

In addition to tests that result in numerical values, there are blood tests that give spot results. The 4DX snap test is the most common spot test used for dogs in veterinary medicine. In this test, blood is mixed with a reagent and then pipetted onto a test kit. If the dog is infected, then blue spots will appear in the test window. These screening tests are interpreted subjectively like a pregnancy test, and are often followed up by additional testing.

Once blood tests have been run, a veterinarian will follow up with the pet parent to go over the results. Even if you don’t understand everything that is written on the printout, it is a good idea to keep a copy for your own records. You can also take notes on the paperwork while the veterinarian is talking. A veterinarian should show you all the results, both normal and abnormal, explain what the abnormal results mean, and provide guidance on what to do next. 

Dog Blood Test Cost

The cost of testing varies based on what test is being run and where the test is being run. The cost of testing includes the cost of labor (paying the veterinary staff), supplies, and paying for the blood analysis machine or paying the reference laboratory for the test. Some testing is less expensive because the test is routine, easy, and the veterinary clinic uses that test for large volumes of patients. Other testing is more expensive based on how labor intensive the test is (for example a blood glucose curve requires day hospitalization, multiple blood draws, and then a veterinarian to analyze the results) or how much the reference lab is charging for the test.

In general, routine complete blood panels cost $100-$300. Specialized testing costs anywhere from $50-$400 or more, depending on the test. Veterinary care is an investment in your dog’s health, but it can be pricey. Pet parents have several options that they can use to offset the cost of veterinary care, such as pet insurance, line of credit, emergency credit card, or wellness plans offered through the veterinary clinic. 

Dog Blood Test Benefits

Having your dog’s blood tested has many benefits that include early detection of disease, infectious disease control, ensuring safe anesthesia, and monitoring medication. Interpretation of blood tests is a nuanced skill that veterinarians develop by taking classes in clinical pathology and years of practice, which is why it is always important to work with a veterinarian you trust to interpret blood test results. By combining your veterinarian’s knowledge with modern lab technology, pet parents can help their dogs live longer, healthier lives.