| Most common panel types | CBC and chemistry panel |
| Species note | Normal reference ranges differ between dogs and cats |
| Kidney markers commonly checked | BUN, creatinine, SDMA, phosphorus |
| Primary liver enzyme monitored | ALT (dogs); ALT and AST in both species |
| Thyroid test added for | Senior cats (T4 for hyperthyroidism screening) |
| Fasting before blood draw | Usually 8 to 12 hours; always confirm with your vet |
Why vets run blood panels
A physical exam tells a vet a great deal, but many organ problems produce no visible signs until they are well advanced. Blood panels fill that gap by measuring what is happening inside the body at a cellular and chemical level. Vets use them at annual wellness visits, before anesthesia, when a pet seems unwell, and to track known conditions over time.
Blood work is also a baseline tool. A result within the reference range today becomes a comparison point years from now, so trends are visible before numbers tip outside normal. This is one reason annual wellness exams typically include at least a basic panel for adult and senior pets.
Two panels appear on most vet reports: the CBC and the chemistry panel. They are often run together and interpreted as a set.
CBC (complete blood count)
A panel measuring the number and appearance of red blood cells, white blood cells, and platelets. It helps detect anemia, infection, inflammation, and clotting problems.
Chemistry panel
A group of blood tests that measure enzymes, proteins, electrolytes, and waste products to assess organ function, especially the liver, kidneys, and pancreas.
BUN (blood urea nitrogen)
A waste product filtered by the kidneys. Elevated BUN can indicate reduced kidney function, dehydration, or a high-protein diet, depending on context.
ALT (alanine aminotransferase)
An enzyme found mainly in liver cells. When liver cells are damaged, ALT leaks into the bloodstream, so elevated levels often signal liver stress or disease.
Creatinine
A muscle waste product filtered by the kidneys. It rises in the blood when kidney filtration slows, and is often evaluated alongside BUN for a fuller picture of kidney health.
Hematocrit (PCV)
The percentage of blood volume made up by red blood cells. A low hematocrit indicates anemia; a high reading can suggest dehydration or, rarely, excess red cell production.
Glucose
Blood sugar. Persistently elevated glucose can point toward diabetes mellitus, while very low glucose may indicate hypoglycemia, which can be an emergency.
Total protein
Measures albumin and globulin combined. Abnormal levels can reflect liver disease, kidney protein loss, dehydration, or immune system activity.
Reading the CBC: cells and counts
The CBC measures the three main cell populations in blood. Each tells a different story.
Red blood cells (RBCs) and hematocrit: These carry oxygen. Low RBC numbers or a low hematocrit indicate anemia, which can stem from blood loss, destruction of cells, or failure to produce enough. High values often point to dehydration rather than disease.
White blood cells (WBCs) and differential: WBCs are the immune system's response force. An elevated count can mean infection, inflammation, or stress. A very low count may mean the immune system is suppressed. The differential breaks WBCs into subtypes (neutrophils, lymphocytes, monocytes, eosinophils, basophils), and the pattern across subtypes helps narrow the cause.
Platelets: These are clotting cells. A low platelet count raises concern about bleeding disorders or certain tick-borne diseases in dogs.
Reference ranges on the printout are species-specific: a number normal for a dog may be outside range for a cat. Always read the range printed alongside the value, not a generic chart.
| Most common panel types | CBC and chemistry panel |
| Species note | Normal reference ranges differ between dogs and cats |
| Kidney markers commonly checked | BUN, creatinine, SDMA, phosphorus |
| Primary liver enzyme monitored | ALT (dogs); ALT and AST in both species |
| Thyroid test added for | Senior cats (T4 for hyperthyroidism screening) |
| Fasting before blood draw | Usually 8 to 12 hours; always confirm with your vet |
Reading the chemistry panel: organs and metabolites
The chemistry panel covers liver, kidneys, pancreas, electrolytes, and blood sugar. Here are the markers owners encounter most often.
Liver markers
ALT is the most liver-specific enzyme in dogs. Elevated ALT signals liver cell damage; how elevated matters, because mild increases can come from medication, recent strenuous exercise, or other causes, while large elevations are more concerning. ALP (alkaline phosphatase) is less specific but rises with liver, bone, or adrenal gland issues. In cats, any ALP elevation warrants attention because cats have very little of it normally.
Kidney markers
BUN and creatinine are the classic kidney markers, but both can be influenced by factors unrelated to kidney function (diet, muscle mass, hydration). Vets now also use SDMA (symmetric dimethylarginine), a newer marker that can flag early kidney decline before creatinine rises noticeably. Phosphorus is tracked alongside these because kidneys regulate phosphorus, and high levels accelerate kidney disease progression.
Glucose
A single elevated glucose reading in a cat may reflect stress rather than diabetes, since cats are prone to stress hyperglycemia during vet visits. Consistent elevation across readings, or a concurrent urinalysis showing glucose in the urine, carries more diagnostic weight.
Electrolytes and total protein
Sodium, potassium, and chloride balance is closely tied to hydration and adrenal gland function. Abnormal potassium, for instance, can point toward Addison's disease in dogs. Total protein and albumin levels reflect liver production, kidney loss, and nutritional status. For context on how diet intersects with these markers, see pet nutrition fundamentals.
What to do with results
A single out-of-range value rarely tells the whole story. Vets interpret results in the context of the pet's age, breed, current medications, recent stress, diet, and clinical signs. Some abnormalities resolve on their own or with minor changes; others prompt further tests such as a urinalysis, ultrasound, or repeat panel in a few weeks.
If your pet is diagnosed with a condition through blood work, managing a chronic condition at home covers the daily care principles that follow. For new owners building a broader understanding of their pet's health, first-time pet owner health essentials is a useful starting point that covers how blood work fits alongside vaccinations, parasite control, and other preventive care.
This article is for general informational purposes only and is not veterinary medical advice. Always consult a licensed veterinarian for guidance on your individual pet's health and test results.