While some conditions can be diagnosed based on a physical exam, others require diagnostic testing to hone in on the correct diagnosis. One of the most common types of the diagnostic test is bloodwork. A wealth of information about a cat’s physiological status and organ functions is discovered by running blood tests.

Blood tests for cats are useful in the following situations:

Your cat’s first veterinary visit

veterinarian playing with kittenYour first veterinary visit is recommended to establish a specific individual’s normal values, which provides a precise basis for comparison for future testing, and also to check for congenital abnormalities or potential concerns.

Semi-annual wellness exams

Semi-annual wellness exams are recommended in conjunction with a thorough physical examination to detect any diseases that are in an early or subclinical stage, when they will be most responsive to intervention.

veterinarianSigns of illness or your cat’s acting abnormally

Blood tests are useful in determining the underlying cause of a cat’s symptoms and in monitoring the cat’s response to treatment.

cat medication

Pre-surgical tests

Bloodwork is an important component of a pre-surgical patient assessment as it provides information on the health of the liver and kidneys, which is very important in formulating a safe anesthesia protocol. This testing can also identify other abnormalities that would be important to be aware of before surgery, such as anemia or abnormal blood clotting.

vet with cat at veterinary hospital

Senior cat wellness exams

Bloodwork is recommended for mature, senior, and geriatric cats as part of their periodic wellness exams.

prescription medication

The Animal Clinic of Billings often sees senior cats return to a youthful state following blood tests that that identified an easily treated disorder.

The Animal Clinic of Billings has a state-of-the-art laboratory that enables us to acquire accurate real-time results rapidly.

veterinarian fixing catThe veterinarian can diagnose illnesses, monitor patient status, and adjust treatments in our hospitalized patients.

Why Cat Bloodwork is Needed

veterinarian kissing cat

Cat bloodwork is essential for veterinarians to effectively diagnose many diseases, and blood tests are often more effective when used in conjunction with other diagnostic tests as well.

For instance, elevated BUN and creatinine levels in a cat’s blood usually indicates a kidney problem may be pressent, but it can also mean the cat may be mildly dehydrated. This is why ordering additional testing is not only important, but often times necessary to obtain the correct diagnosis.

Types of Feline Blood Work

The four most common examples of feline blood work we run in our lab include:

kitten playing with vaccine syringe

Feline Immunodeficiency Virus and Feline Leukemia testing

This is a standard test for kittens and newly adopted cats. These viruses are transmitted by contact with other cats and can become life-threatening. It is essential to know if a cat is positive so that special precautions and monitoring can be instituted to keep them as healthy as possible, and so that protective measures can be implemented for any other cats who share their environment.

veterinarian giving a cat a shot

Complete Blood Count (CBC)

A CBC measures many parameters of the cellular components of the blood: the red blood cells, white blood cells, and platelets.

medical shots for animals

Red blood cells carry oxygen throughout the body. Abnormalities in the size, shape, or number of red blood cells in the blood can all indicate the presence of specific underlying diseases. The number and appearance of the various types of white blood cells circulating in the blood provide information about any inflammatory processes (such as infection) occurring in the body, as well as about immune system function.

cat vaccines

Platelets are an essential component of the blood clotting process, and abnormalities in the number or appearance of platelets in the blood can indicate the presence of specific diseases.

Blood Serum Chemistry

A serum chemistry analysis furnishes a wealth of information about the status of specific organ systems, as well as metabolic processes and electrolyte levels.


This panel is instrumental in determining the cause of a cat’s symptoms, monitoring a sick patient’s response to treatment, and screening for abnormalities before anesthesia.

Total Thyroid Level

Hyperthyroidism is by far one of the most common diseases encountered in cats as they age, causing weight loss, vomiting, heart disease, and other serious problems.

Measuring the level of thyroid hormone circulating in the blood, allows us to diagnose hyperthyroidism and institute treatment, which can often restore these cats to full health.

Our veterinarians also provide fast in-house lab testing for:

veterinarian looking through microscopeCat Urinalysis

By acquiring and testing a sample of your cat’s urine, our veterinarians can evaluate for the presence of many health conditions including kidney disease, diabetes, bladder infections, other bladder problems, and dehydration.

Cat Stool Samples

Fecal samples are routinely evaluated for the presence of intestinal parasites. Additional testing can be performed to look for specific GI infections and other abnormalities.

Cat Cytology

A cat cytology is a visual analysis of a sample of cells under a microscope. The sample may be from the skin or ears, or any tissue in the body accessible with a hypodermic needle. This can be used to diagnose infections, sterile inflammatory lesions, and cancers.


red blood cellsCat blood tests can indicate a deficiency in albumin levels, which indicates a possible liver issue because albumin is produced in the liver. Blood tests can detect abnormal hormonal-chemical responses to environmental and internal stimuli in cats as well, which indicates a potential issue with the patient’s endocrine system.

Once we establish a correlation, we can order any subsequent feline blood work procedures necessary to arresting and treating the condition. In this way, feline blood tests serve as very valuable tools in a veterinarian’s toolkit for helping to detect, identify, diagnose and ultimately treat illness or disease.

veterinarian teaching children to care for animalsAfter we process your cat’s bloodwork sample, one of our veterinarians will discuss any abnormal findings with you. We will explain the possible causes of any abnormalities in the following parameters, and recommend any further diagnostics that may be necessary to definitively determine the cause so that the most effective treatment can be instituted.

The results of feline blood tests are essential to helping veterinarians diagnose and treat medical conditions both within the blood itself, as well as in organs such as kidney and liver. During a blood test for cats, various chemicals in the blood stream are analyzed. Such as:

  • CBC (Complete Blood Count): This blood panel measures the following cellular components of blood:
  • Red Blood Cells: These are the cells that carry oxygen throughout the body. An abnormally low level of RBCs is called anemia. This is caused by a wide variety of conditions, including blood loss, immune-mediated diseases, bone marrow disorders, and chronic diseases.
  • White Blood Cells: These cells As part of the body’s immune system, these cells serve to respond to damage and inflammation as well as fight off infections.
  • Neutrophils: These WBCs are the first responders to areas of inflammation and infection in the body, where they kill pathogens and send out signals to recruit other WBCs. These can be elevated in the presence of infection, inflammation, or cancer. They can be decreased in any disease that impairs the immune system, or in the presence of a severe infection.
  • Eosinophils and Basophils: These WBCs are primarily responsible for responding to parasitic infections. They also play an vital role in allergies and asthma. Usually, an increase in either of these types suggests the presence of a parasite, an allergy, or asthma.
  • Lymphocytes: These WBCs perform a variety of essential functions, including the manufacture of antibodies against pathogens and the destruction of pathogens and infected and abnormal cells. These are the cells that respond to a vaccine to generate immunity. These cells can be elevated in the presence of infection, inflammation, or cancer. They can be decreased in any disease that impairs the immune system, or in the presence of a severe infection.
  • Monocytes: These WBCs function as a “cleanup crew” at sites of infection and inflammation, digesting dead cells and debris in addition to pathogens. These cells are elevated in the later stages of infection, with chronic inflammation, and with some types of cancers.
  • Platelets: These cell fragments play an essential role in blood clotting. Decreased levels can result from some infectious diseases, immune-mediated conditions, bone marrow disorders, and as a result of hemorrhage.
  • Serum Biochemistry: This blood panel provides a great deal of information about the body’s metabolic processes and organ functions.
  • Albumin: The main protein in the blood, albumin is essential to maintain blood pressure and transporting a variety of important substances in the blood. Low albumin may result from disease of the liver, kidneys, GI tract, or blood vessels.
  • Globulins: In addition to transporting numerous substances throughout the body, this group of blood proteins also plays an essential role in the immune response to infections. A decrease in globulins may indicate a problem with the liver, GI tract, or immune system. Globulins can be elevated in response to infections, as well as in some types of cancers.
  • Total Protein: The overall level of proteins in the blood, the primary components of which are albumin, globulins, and fibrinogen (a protein necessary for blood clotting).
  • Glucose: The level of sugar in the blood. An elevated level is suggestive of diabetes, although stress can also result in temporarily increased levels. Decreased blood glucose can occur from prolonged fasting in toy-breed dogs and puppies, from liver disease, and severe infections.
  • Alkaline Phosphatase (ALP): This enzyme is contained within liver cells, and elevated blood levels may result from damage to the liver and biliary system, from Cushing’s Disease (hyperadrenocorticism), or from steroid administration. It is commonly elevated in young growing animals because it is also produced by growing bones.
  • Alanine Aminotransferase (ALT): This enzyme is present in the liver, muscles, and heart. An elevated ALT may result from injury to any of these organs.
  • Amylase: This enzyme is produced by the pancreas and breaks down sugars in the intestine. It can be elevated in cases of pancreatic, GI, or kidney disease.
  • Lipase: This digestive enzyme is produced primarily by the pancreas. An elevated level may indicate disease of the pancreas, GI tract, or kidneys.
  • Cholesterol: An essential component of cells and participant in many processes throughout the body. An elevated level can be seen with liver, pancreatic, or endocrine disorders. A decreased level may indicate liver, endocrine, metabolic, or nutritional disorders.
  • Gamma-Glutamyl Transferase (GGT): A protein present in cells in the liver, biliary system, and pancreas. Increased levels can be seen with disorders of any of these organs.
  • Total Bilirubin: Bilirubin is a product of the breakdown of old red blood cells, and is eliminated in bile and urine. An elevated blood level can cause icterus (jaundice)—a yellow tint to the skin and whites of the eyes. Elevation can be the result of increased red blood cell destruction (usually immune-mediated), liver disease, or blockage of the biliary system.
  • Blood Urea Nitrogen (BUN): A waste product of protein breakdown by the liver, this metabolite is eliminated by the kidneys. An elevated level may result from dehydration, a high protein diet, kidney disease, or disorders of the urinary tract. BUN can be decreased in cases of reduced protein intake and liver disease.
  • Creatinine: A waste product of muscle metabolism, creatinine is eliminated by the kidneys. An elevated level may result from dehydration, kidney disease, or urinary tract disease. A decreased level can be seen in patients with decreased muscle mass.
  • Calcium: This mineral is essential for numerous processes in the body. Elevated levels occur in cases of hyperparathyroidism, hypoparathyroidism (Addison’s Disease), kidney disease, vitamin D overdoses, and some cancers. Decreased levels occur with kidney disease, hypoparathyroidism, and in some nursing females.
  • Phosphorus: Another crucial mineral in the body. Abnormal levels usually indicate a problem with the kidneys or parathyroid glands.
  • Serum Electrolytes: This blood panel measures the circulating level of several important electrolytes.
  • Sodium (Na): Sodium is a tightly-regulated electrolyte essential in the regulation of blood volume and blood pressure, as well as in numerous cellular processes. Sodium can be elevated with dehydration, endocrine disorders, and excessive intake. Decreased levels can result from endocrine diseases, heart failure, liver disease, kidney disease, and excessive water intake.
  • Potassium (K): Another electrolyte that serves many essential roles in the body. It can be elevated in cases of endocrine disorders and kidney and urinary diseases. A decreased level usually indicates an endocrine or GI disorder, or inadequate intake.
  • Chloride (Cl): This electrolyte can be elevated in the presence of kidney or GI disease, and can be decreased in GI disease or when excess sodium is lost from the body.
  • Symmetric Dimethylarginine Assay: This blood test measures SDMA, a molecule that is produced by the body at a relatively constant rate, and is eliminated by the kidneys. This is currently the earliest marker of kidney disease for animals, enabling detection of as little as 25% loss of function.
  • Total Thyroxine Level: This blood test measures thyroid activity. Hypothyroidism is a relatively common disorder in dogs, causing decreased energy, weight gain, and a thinning coat. Hyperthyroidism frequently develops in older cats, causing weight loss despite a good appetite, and putting a strain on the heart. Both of these conditions are treatable once diagnosed.

Additional chemistry panels measure the following cellular components of blood in cats:

  • Albumin (ALB): This is a serum protein that helps evaluate hydration, hemorrhage and intestinal, liver and kidney disease.
  • Alkaline phosphatase (ALKP): Elevations in this test may indicate liver damage, Cushing’s disease or active bone growth in a young cat. This test is especially significant in cats.
  • Alanine aminotansferase (ALT): This test may determine active liver damage, but does not indicate the cause.
  • Amylase (AMYL): Elevations in this test indicate pancreatitis or kidney disease.
  • Aspartate aminotransferase (AST): Increases in this test may indicate liver, heart or skeletal muscle damage.
  • Blood urea nitrogen (BUN): This test determines kidney function. An increased level is called azotemia and can be caused by kidney, liver and heart disease as well as urethral obstruction, shock or dehydration.
  • Calcium (Ca): Changes in the normal level of this test can indicate a variety of diseases. Tumors, hyperparathyroidism, kidney disease, and low albumin are just a few of the conditions that alter serum calcium.
  • Cholesterol (CHOL): This test is used to supplement diagnosis of hypothyroidism, liver disease, Cushing’s disease and diabetes mellitus.
  • Chloride (Cl): Chloride is an electrolyte that is typically lost with symptoms like vomiting or illnesses such as Addison’s disease. Elevations often indicate dehydration.
  • Coristol (CORT): Cortisol is a hormone that is measured in tests for Cushing’s disease (the low-dose dexamethasone suppression test) and Addison’s disease (ACTH stimulation test).
  • Creatinine (CREA): This test reveals kidney function and helps distinguish between kidney and non-kidney causes of elevated BUN.
  • Gamma Glutamy transferase (GGT): This is an enzyme that indicates liver disease or corticosteroid excess.
  • Globulin (GLOB): This is a blood protein that often increases with chronic inflammation and certain disease states.
  • Glucose (GLU): Glucose is a blood sugar. Elevated levels may indicate diabetes mellitus. Low levels can cause collapse, seizures or coma.
  • Potassium (K): This is an electrolyte typically lost with symptoms such as vomiting, diarrhea or excessive urination. Increased levels may indicate kidney failure, Addison’s disease, dehydration or urethral obstruction. High levels can lead to cardiac arrest.
  • Lipase (LIP): Lipase is an enzyme that may indicate pancreatitis.
  • Sodium (Na): Sodium is an electrolyte often lost with signs vomiting, diarrhea, kidney disease and Addison’s disease. This test helps indicate hydration status.
  • Phosphorus (PHOS): Elevations in this test are often associated with kidney disease, hyperthyroidism and bleeding disorders.
  • Total bilirubin (TBIL): Elevations in this test may indicate liver or hemolytic disease. This test helps identify bile duct problems and certain types of anemia.
  • Total protein: This test indicates hydration status and provides additional information about the liver, kidneys and infectious diseases.
  • Thyroxine (T4): Thyroxine is a thyroid hormone. High levels indicate hyperthyroidism in cats.


Let our highly trained and experienced team of veterinarians and veterinary technicians help you keep your cat as happy and healthy as they can be.

Call the Animal Clinic of Billings to schedule your cats next wellness examination with us today!   REQUEST AN APPOINTMENT