My Dog’s Blood Tests Are Abnormal – What Does This Mean?

Have you been told that your dog’s blood tests are abnormal? First, you’ve come to the right place — we can help you sort it out. Second, although this sounds scary, not all abnormal blood tests are life-threatening or serious.

What are blood tests?

Blood tests (aka “blood work”) are common tests that all dogs and cats who visit a veterinarian have done at some point in their lives. There are many different blood tests. The most common tests include the complete blood count (CBC), general chemistry profile and electrolyte panel. 

1. CBC – evaluates the blood cell (red blood cells, white blood cells and platelets) quantities and characteristics.

2. General chemistry profile – measures kidney values, liver enzymes, protein quantity, and lipids (cholesterol, triglycerides).

3. Electrolyte panel – measures the sodium, potassium and chloride. Many internal medicine diseases alter the electrolytes and you may not even know they are abnormal until serious symptoms arise.

There are hundreds of additional specialized blood tests that evaluate for specific symptoms and diseases. Far too many to write about here, but we know all about them, so if you have questions contact us and we can help.

When does my dog need blood tests?

Blood tests are frequently performed when you bring your dog into the veterinarian:

1. At their annual checkup – being proactive and finding a problem before it’s a “problem” may prevent serious health issues.

2. If your veterinarian detects an abnormality during examining your pet. For example, enlarged lymph nodes, an abnormal swelling in the abdomen or a fever.

3. If you’ve noticed abnormal symptoms, or are concerned about how your pet may be acting.

4. If your pet is to undergo general anesthesia for a medical procedure such as endoscopy, dental cleaning or surgery.

Does my pet need blood tests every year?

Your pet should see their veterinarian at least annually — some pet’s need more frequent visits due to age (young or old), ongoing treatments or chronic illnesses. However, even if your pet is not sick, annual blood tests can be very helpful for the following reasons:

1. Some diseases may start long before there are symptoms and blood tests early may reveal these issues. Detecting a disease in its early stages can go a long way toward effective treatment.

2. When disease is diagnosed, it’s helpful to have a previous baseline value to understand when the abnormality may have started. If your pet has never had blood tests, it is difficult to know when the problem may have started.

Preventative care usually leads to a longer, healthier life, so understanding your pet’s lipids, glucose, electrolytes positions your pet in the best place for a full happy life.

How is my dog’s blood sampled?

A veterinarian or a veterinary technician (aka “vet tech”) samples your dog’s blood via a procedure called “venipuncture” (aka “blood draw”). This is almost exactly how people have their blood sampled. In your pet’s case, one vet tech will gently hold your dog while they are sitting or lying down, while the other vet tech will insert a small needle into a vein and withdraw a small amount (typical 2-3 mLs) of blood into a syringe. The procedure does not typically require sedation, feels the way that it feels when you have your blood drawn (okay, not fun, we get that) and is completed in 20-30 seconds. A “band-aid” (wrap) will be placed over the area (leg) where the blood was sampled and kept on tight for 10-15 minutes so the vein does not bleed.

Many different veins can be used to draw blood from. There are veins on all four legs, and even the jugular vein (neck) can be sampled — we tend to avoid sampling from the jugular vein because many of our patients have disease that may cause a delay in their blood clotting, and it is difficult to put a bandage to promote clotting around the neck.

What are some of the common blood tests abnormalities?

There are many different changes that can be detected in your dog’s CBC, general chemistry profile and electrolyte panel. Here are a few that occur commonly.

Common abnormalities found in dogs’ complete blood count (CBC)

1. Too few red blood cells (RBCs) — Not enough red blood cells is called anemia. Dogs can become anemic if there is ongoing bleeding — commonly in the abdomen, stomach, intestines or colon. Anemia can also occur if your body’s immune system is attacking and destroying RBCs in the case of a disease called immune-mediated hemolytic anemia(IMHA). Did you know that blood cells have their own species-unique life-expectancy? In dogs an RBC has an average life-span of 110 days, whereas in a cat, their RBCs live 70 days. At the end of an RBC’s life-span, it is quietly replaced by a new RBC which is made in the bone marrow. Therefore, another cause of anemia is bone marrow suppression and lack of production of new RBCs. If the naturally dying RBCs are not constantly replaced, anemia will occur. When the available RBCs reach a critical low, a blood transfusion from a blood bank may be needed.

2. Too many white blood cells (WBCs) — It is understandable to think that if your dog has too many WBCs, they must have an infection. Although this is one possibility, it’s not the only one (and not the most common reason!). Inflammation causes high WBCs. Infection causes inflammation, but there are other non-infectious reasons for inflammation. In fact, even stress — the stress of going to the vet! — can cause a slight increase in certain WBCs which is completely normal. High WBCs can also be seen with serious diseases such as cancers. There are multiple types of WBCs, and whether to worry or not comes down to how elevated and which WBCs are involved, your dog’s age and symptoms and the results of other testing — for example, X-rays (radiographs), ultrasound, CT scan imaging, and endoscopy.

3. Too few platelet cells (thrombocytopenia) – Platelets are small cells that circulate in the bloodstream along with the RBCs and WBCs and, like the other blood cells, are produced in the bone marrow. Platelets have a very important job: to help form a clot to prevent bleeding. So, yes, it can be scary when your dog has low platelets. This can occur when there is active bleeding (internally, in the stomach, intestines, colon), if the bone marrow is not producing platelets (bone marrow suppression) or if the immune system is destroying platelets (immune-mediated thrombocytopenia). When your dog’s CBC shows low platelets, our first step is to perform a “manual platelet count”. For this, our vet techs evaluate the blood under a microscope and use a standard formula to calculate the total platelet count; this is oftentimes more accurate than an automated analyzer. If confirmed low, then testing to identify possible causes are recommended — for example, infectious disease testing, X-rays, ultrasound, and sometimes even an aspirate and core biopsy of the bone marrow.

Common abnormalities found in dogs’ general chemistry profile

1. Liver enzyme elevations – this can be caused by a wide range of diseases and medications. There are multiple liver enzymes on the chemistry profile — which one (or multiple) that are elevated is the first key to what may be the cause. The two most common enzymes to be elevated are the ALT and the ALP (or ALKP). Elevation in ALT occurs during liver injury which can occur in many ways: infection, toxins such as Sago palms, cancer, immune-mediated liver disease (chronic active hepatitis), copper storage disease, medications, among others. Elevation in ALP can be normal in very young puppies, caused by congenital liver diseases, or caused by diseases such as diabetes mellitus, Cushing’s disease, cancer, infectious diseases (e.g. Leptospirosis) and gallbladder and biliary diseases. There are several groups of medications well-known for increasing ALP in dogs, including “steroids” (prednisone) and anticonvulsants (phenobarbital). Further evaluation requires a thorough understanding of any exposure to toxins and medications, and by performing additional testing which might include X-rays, ultrasound, CT scan and sometimes liver biopsy.

2. Kidney value elevations – there are multiple parameters on the chemistry profile that can indicate the health of the kidneys: SDMA, BUN (blood urea nitrogen) and creatinine are the main ones. Elevations in these numbers does not always mean kidney failure or chronic kidney disease, for example, dehydration can influence these results. The kidney values always need to be evaluated along with a urinalysis to give an accurate picture of your dog’s kidney health. Diseases affecting the kidneys can include congenital (renal dysplasia), infection, cancer, stones (bladder, kidney) and sometimes age (chronic kidney disease, CKD). When your dog’s kidney values are elevated, further investigation into all of these causes with additional blood and urine testing, blood pressure measurement, X-rays, ultrasound can be helpful to determine the cause.

3. High, or low blood sugar (glucose) – elevated glucose (hyperglycemia) can simply be due to stress, or it can be a sign of diabetes mellitus; there are ways to differentiate the two with additional testing. Low blood sugar (hypoglycemia) is less commonly seen in dogs, however when this is occurring, it can be from serious conditions such as cancer (insulinoma), Addison’s disease, or overwhelming infection. Toy breeds (especially puppies) may have hypoglycemia if they are not eating adequate calories to maintain their blood sugar.

4. Lipids – elevated lipids (triglycerides and cholesterol) are frequently encountered in dogs. A cause of this could be due to an inappropriate (fatty) diet. However, there are other diseases to consider including hypothyroidism, Cushing’s disease, diabetes mellitus, congenital hyperlipidemia (Miniature schnauzers), kidney disease, liver and gallbladder disorders. Further testing and understanding your pet’s diet (and snacks!) and full medical history is important to begin to unravel why the blood is too “fatty”. It’s important to keep in mind that, just like in humans, fasted (no food for at least 8 hours) blood testing is needed for an accurate reading on the lipids.

5. High, or low blood proteins – the two main blood proteins are albumin and globulins. Albumin performs many important jobs. There are no diseases that cause an elevated albumin — this is due to dehydration. Low albumin on the other hand can be caused by liver failure (it is made in the liver), or loss through feces (IBD, inflammatory bowel disease, protein-losing enteropathy) or urine (protein-losing nephropathy / proteinuria). So, when the albumin is low, it is important to understand the health of the liver, kidneys and intestinal tract. Globulins are akin to “antibodies”. When globulins are very low, this can be a sign of gastrointestinal disease, hemorrhaging, immune deficiency and certain infectious diseases. Elevated globulins on the other hand can be a sign of chronic inflammation, infection and even cancer. When the albumin is low, or the globulins are high or low, these warrant further investigation.

6. Calcium – high (hypercalcemia) or low (hypocalcemia) calcium can be detected on a general chemistry profile. Both high and low calcium can be caused by parathyroid disease (hyperparathyroidism, hypoparathyroidism). Elevated calcium can also be a marker for certain cancers, and serious fungal infections, so investigating the cause of any calcium abnormality in dogs is very important, which may include radiographs (X-rays), ultrasound, infectious disease testing, specialized hormonal (parathyroid) blood testing.

Common abnormalities found in dogs’ electrolyte panel

1. Potassium – in a variety of situations and disease states, the potassium can be either elevated (hyperkalemia) or low (hypokalemia). An increased potassium is typically more concerning than a low potassium, as the consequences of a high potassium can be fatal (high potassium can interfere with the electrical activity of the heart, and when very high, can cause the heart to stop beating). Diseases that cause hyperkalemia including acute kidney failure, inability to urinate from obstruction, parasite (Whipworm) infection and Addison’s disease. Hypokalemia can be caused by poor diet, intestinal disease, hyperaldosteronism, kidney disease, and certain medications (diuretics).

2. Sodium – elevated sodium (hypernatrenia) can have serious neurologic side effects if the sodium level is very elevated, and remains high for a significant length of time. Causes of hypernatremia include diabetes insipidus (not the sugar diabetes which is diabetes mellitus), lack of access to water to drink, a hormonal disease called hyperaldosteronism and dehydration from severe gastrointestinal issues (vomiting, diarrhea). Ingestion of certain items have been shown to cause hypernatremia, including salt, sea water, and certain jerky treats. Very high sodium needs immediate and intensive care to safely lower it into the normal range.

If your dog’s blood tests look concerning, we can help.

If your dog’s blood tests show abnormalities, we can help sort it out. We specialize in internal medicine diseases and are trained in interpreting these blood tests, performing additional specialized testing and treatment of diseases that affect the inner workings of the blood stream.