Vomiting in Dogs – Which Blood Tests to Ask For

Wondering what a full interpretation looks like? See a sample report →

Why Is Vomiting in Dogs a Concern?

Vomiting is a common clinical sign that can be alarming to dog owners. It often prompts immediate concern and questions about underlying causes, especially when it persists or recurs frequently. In dogs, vomiting can indicate a wide range of issues from dietary indiscretion to more serious conditions like gastrointestinal obstruction or organ dysfunction.

The significance of vomiting lies in its potential to signal systemic health problems that require prompt attention. For instance, persistent vomiting can lead to dehydration and electrolyte imbalances, which are critical concerns for the overall well-being of your dog. Additionally, chronic vomiting may be a symptom of underlying gastrointestinal diseases such as inflammatory bowel disease or cancer.

When evaluating a dog with vomiting, veterinarians often look beyond just the immediate cause. Blood tests can provide valuable insights into organ function and systemic health. For example, elevated liver enzymes (ALT, AST) might suggest hepatic involvement, while changes in kidney markers like BUN (Blood Urea Nitrogen) or creatinine could indicate renal compromise.

Understanding why vomiting is a concern helps guide the diagnostic process towards identifying the root cause. This approach ensures that appropriate treatment can be initiated early to address any underlying issues and prevent further complications. For instance, if vomiting persists despite dietary changes and symptomatic therapy, it may be indicative of an underlying systemic issue such as pancreatitis or liver disease.

Moreover, vomiting in dogs can also signal metabolic disorders like hypothyroidism or hyperthyroidism (though the latter is less common), which require specific diagnostic tests beyond routine blood work. Additionally, certain infectious diseases and parasitic infestations may present with vomiting as a primary symptom, necessitating further investigation through specialized testing.

In summary, vomiting in dogs should not be dismissed lightly due to its potential to indicate serious health issues that can affect multiple organ systems. Early detection and intervention are crucial for improving outcomes and quality of life for affected dogs.

What Does CBC Reveal About Vomiting?

The Complete Blood Count (CBC) is a vital tool in assessing dogs experiencing vomiting. It provides insights into inflammation, anemia, and infection that may be contributing to the symptoms. When interpreting a CBC for a dog with vomiting, veterinarians look at several key components of the blood sample.

One critical aspect of the CBC is the white blood cell (WBC) count. An elevated WBC count can indicate inflammation or an active infection in the body. For instance, if there’s an increase in neutrophils, it might suggest a bacterial infection that could be causing gastrointestinal distress and vomiting. Conversely, a low WBC count may point to conditions like viral infections or bone marrow suppression. It is important to note that the reference intervals for WBC counts can vary based on the laboratory used, so veterinarians must consult the specific lab report for accurate interpretation.

Another important component is the red blood cell (RBC) count and hemoglobin levels. These can help identify anemia, which might occur due to chronic illness, blood loss from ulcers or parasites, or other causes of gastrointestinal bleeding. Pale gums observed during a physical exam often correlate with low RBC counts and hemoglobin levels. Anemia in dogs can be caused by various factors such as nutritional deficiencies, chronic diseases like kidney failure, or parasitic infections.

Platelet counts are also crucial in assessing dogs that vomit frequently. Low platelets can indicate immune-mediated thrombocytopenia (IMT), which is an autoimmune condition where the body attacks its own platelets, leading to bleeding tendencies. This could present as blood in the vomit or bruising under the skin. Additionally, a low platelet count might also suggest other conditions such as disseminated intravascular coagulation (DIC) or thrombocytopenia secondary to certain medications.

Other components of the CBC that can provide valuable information include the hematocrit and mean corpuscular volume (MCV). The hematocrit measures the proportion of red blood cells in whole blood, while MCV indicates the average size of RBCs. Both these parameters are useful for diagnosing different types of anemia. For example, a low MCV suggests microcytic anemia, which could be due to iron deficiency.

See the full reference intervals for the dog — every value cited to the laboratory document or paper it came from.

How Do Liver Enzymal levels, such as ALT and AST, can provide valuable insights into liver health when a dog is vomiting. Elevated levels of these enzymes suggest damage or leakage from liver cells, which could be linked to various conditions that might cause gastrointestinal distress.

ALT (alanine transaminase) primarily reflects hepatocellular injury in dogs. When ALT is markedly elevated above the reference range (17-95 U/L), it indicates significant liver cell damage. However, if AST levels are also high alongside CK, muscle injury should be considered as a contributing factor. In cases where vomiting is present and other clinical signs suggest liver involvement, an increased ALT level can point towards hepatocellular issues.

AST (aspartate transaminase) is less specific to the liver compared to ALT but still plays a role in assessing liver health. Elevated AST levels may indicate either muscle or liver injury. When interpreting AST results alongside other markers like CK and ALT, veterinarians can better differentiate between hepatic and muscular causes of elevated enzyme levels.

When liver enzymes are above their reference range, it’s important to consider the broader clinical picture. Other blood tests such as GGT (gamma-glutamyl transferase) or bile acids might be necessary to further evaluate liver function. Additionally, imaging studies like ultrasound can help visualize any structural changes in the liver that could explain elevated enzyme levels and vomiting.

Enzyme	Reference Range (17-95 U/L, 18-56 U/L)	Interpretation of Elevated Levels
ALT	17-95 U/L	Markedly elevated levels indicate significant hepatocellular damage.
AST	18-56 U/L	Elevated levels may suggest either muscle or liver injury, requiring further differentiation with other markers.

In an affected dog where vomiting is a symptom and liver enzyme levels are elevated, the clinical context becomes crucial. For instance, if AST remains consistently high while ALT fluctuates, it might indicate ongoing muscular damage alongside potential hepatic issues. Conversely, if both enzymes rise sharply in conjunction with other signs of liver dysfunction (such as jaundice or lethargy), a more severe hepatopathy is likely.

It’s also important to note that the interpretation of these enzyme levels should be done in conjunction with clinical symptoms and additional diagnostic tests. For example, if GGT levels are elevated alongside ALT and AST, it may suggest cholestasis or bile duct obstruction, which can contribute to vomiting through increased pressure within the biliary system.

What Kidney Markers Should Be Checked for Dogs With Vomiting?

When a dog is vomiting, kidney function can be compromised due to dehydration or underlying conditions. Blood tests like BUN (blood urea nitrogen), creatinine, and SDMA (symmetric dimethylarginine) are crucial in assessing the health of your pet’s kidneys.

BUN levels rise when there’s reduced renal excretion, indicating that the kidneys may not be filtering waste products effectively. This can happen due to dehydration from vomiting or other causes like gastrointestinal bleeding. Creatinine is another marker for kidney function; it increases when glomerular filtration rate decreases, which could indicate pre-renal (dehydration), renal (kidney disease), or post-renal issues. SDMA, on the other hand, provides an early indication of reduced kidney function by reflecting changes in glomerular filtration rate before creatinine levels rise significantly.

It’s important to interpret these markers alongside clinical signs and other blood tests for a comprehensive evaluation. For instance, if your dog is vomiting and has elevated BUN or SDMA but normal creatinine, it might suggest early-stage kidney dysfunction due to dehydration rather than advanced renal disease. Conversely, markedly elevated levels of all three markers could indicate more severe kidney impairment requiring immediate veterinary attention.

SDMA is particularly useful because its reference interval is not as affected by muscle mass and protein intake compared to creatinine, making it a reliable indicator for early-stage chronic kidney disease (CKD). Elevated SDMA can also be seen in dogs with acute kidney injury due to toxins or other causes of sudden renal impairment.

When evaluating these markers, it’s crucial to consider the dog’s overall health status and any concurrent illnesses. For example, if a vomiting dog has normal BUN but elevated creatinine, this could suggest an obstruction downstream from the kidneys (post-renal cause) rather than kidney disease itself. Similarly, if SDMA is within the reference range but BUN is high, it might indicate gastrointestinal bleeding or other non-kidney related causes of increased protein catabolism.

Why Are Electrolyte Levels Important in Vomiting Cases?

Electrolytes such as sodium, potassium, and glucose play a critical role when your dog is vomiting. These markers help us understand the underlying cause of your pet’s condition and guide appropriate treatment. For instance, electrolyte imbalances can indicate dehydration, kidney dysfunction, or metabolic disorders that require immediate attention.

Sodium levels are particularly important because they indicate whether your dog has lost too much water or retained too much salt. When sodium is above the reference range, it suggests a free-water deficit, often due to dehydration from vomiting or diarrhea. Conversely, if sodium is below normal, it could mean that your pet’s body retains more water than necessary, which can happen with kidney issues or certain medications like diuretics.

Potassium levels are also crucial because they reflect muscle and nerve function. A potassium level that is markedly elevated might indicate severe vomiting leading to significant loss of stomach acid (which contains potassium), or it could be a sign of an underlying condition like hypoadrenocorticism, where the body doesn’t produce enough hormones to regulate electrolytes properly.