Blood Work is Important for Senior Pets

A vet holding a brown dog

What Is Blood Work and Why Is It Important for Senior Pets?

Pets, just like humans, encounter health problems as they age, but cats and dogs age differently and more quickly than humans. Furthermore, pets typically don’t show outward signs of age-related illness until disease becomes advanced. A physical examination won’t always be enough to tell your veterinarian what they need to know about your pet’s health. Your veterinarian may need to perform blood work to get a clearer picture of your pet’s condition.

Blood Work“Blood work” is the collective term for a series of blood tests done by a veterinarian to find out what’s going on inside your pet. Since blood is responsible for carrying nutrients, hormones, proteins, and minerals throughout the body, its contents provide a veterinarian with a lot of insight about how your pet’s body is functioning and whether or not there are problems that can’t be detected from the outside.

A veterinarian looks at two main categories when performing blood work: Blood Chemistry and Complete Blood Count. A Blood Chemistry Panel measures the levels of chemicals found in the blood of your pet including electrolytes, blood glucose, blood urea nitrogen, cholesterol, and much more. These measurements give your veterinarian insight into how your pet’s organs are functioning.

A Complete Blood Count test measures the numbers of different types of blood cells in your pet’s body, like red blood cells, white blood cells, and platelets. These measurements help your veterinarian understand how your pet’s body is functioning and whether the immune system is responding to disease. The resulting levels from both Blood Chemistry and Complete Blood Count tests are compared to normal ranges for your pet’s species and may also be compared to your pet’s test results in the past, referred to as “Baseline” or normal for your pet. A veterinarian may perform more specific blood tests beyond CBC and Blood Chemistry if they believe it’s appropriate for your pet due to their age or specific symptoms and may perform some of these test as part of their routine bloodwork.

A Few Age-Related Diseases Veterinarians Diagnose with the Help of Blood Work:


Diabetes is not uncommon in older pets. It is in essence, an abnormally high level of blood glucose resulting from insufficient insulin production in the pancreas and/or insulin resistance of the body. Both cats and dogs can develop diabetes, especially if they are overweight and inactive. Pets develop diabetes over time with gradually increasing blood glucose levels as the disease advances. Routine blood work can identify above average blood glucose and give the veterinarian and pet owner an opportunity for early treatment and lifestyle changes that can help prevent the disease from becoming severe.

Kidney Disease

Kidney or Renal Disease occurs when the kidneys are no longer able to properly filter waste products from the blood and expel them through the urinary tract. This can be caused by blockages like kidney stones, advanced age, or damage to the kidney tissues. The buildup of waste in the bloodstream is called azotemia, high levels of blood urea nitrogen (BUN) and serum creatinine. A blood chemistry panel done by your veterinarian can detect these excessive waste levels and help your vet determine the best way to treat your pet for kidney disease. What is Blood Work and why is it Important for Senior Pets?


Unfortunately, pets are more prone to various cancers as they age. As in humans, cancer in cats and dogs comes in a wide variety of forms, locations, and severities. Cancers are essentially cells in a pet’s body that are growing abnormally and may invade other parts of the body. There is no single test or indicator for all types of cancer, and blood work may not reveal the presence of cancer, especially early on. A veterinarian will take into account an animal’s symptoms, the presence of any masses in the body, biopsies, and the results of blood work to diagnose cancer in a pet.


Hyperthyroidism is most common in older cats but can sometimes affect dogs as well. It is a disease of the thyroid gland in the neck that results in overproduction of thyroid hormone. This is often due to an enlarged thyroid affected by a benign or non-cancerous tumor. Hyperthyroidism can cause weight loss, excessive thirst and urination, vomiting, diarrhea, and hyperactivity. Your veterinarian can detect the amount of thyroid hormone in your pet with blood work and develop a treatment plan for them. Hyperthyroidism can come on gradually and early detection is always best to prevent more severe symptoms.

Importance for Senior Pets

Beyond being a tool for diagnosing the presence of a disease, blood work is often used by veterinarians to eliminate the possibility of certain diseases. Ruling out some of the possible causes of a pet’s symptoms is important because it tells your vet where to focus their efforts in evaluating and treating your pet.

Since older pets are more prone to diseases that progress gradually as their bodies age, regular blood work is an important tool because it shows changes in the pet’s body function over time. Getting blood work done annually for senior pets gives your vet a clear record of changes in your pet’s health over time and can allow for earlier treatment of disease. It’s an easy way to be proactive in giving older pets the best quality of life possible.

If you’d like to schedule your pet for bloodwork, give us a call at 417-866-6681 or visit our website to request an appointment.