From time to time, your veterinarian might recommend running blood tests on your pet, especially if your pet is a senior. It may seem strange to run blood work on an apparently healthy animal, but not only is it good to get baseline numbers for older pets, but occasionally health issues are discovered through routine tests such as blood work.
If your veterinarian recommends blood work, he or she is likely talking about running a comprehensive panel, including a complete blood count (CBC), a full chemistry and, if your pet is older, a thyroid level.
Complete blood count
A complete blood count (or CBC) tells your veterinarian about your pet’s red blood cells, white blood cells and platelets levels.
- White blood cells fight infection. An increase in the number of white blood cells can indicate mild or severe infections. Sometimes, overwhelming infections can deplete white cell lines, leading to a decrease in their numbers.
- A CBC will easily show discrepancies in red blood cell levels. The body depends on red blood cells to carry blood to organs and muscles. Low numbers of red blood cells are called anemia, which can be life threatening. When a pet is anemic, his tissues stand the chance of being deprived of oxygen. Red blood cell levels can also be too high, as is often the case in extreme dehydration.
- Platelets are necessary for blood clotting. When platelet levels are low, your pet runs the risk of life-threatening clotting disorders.
The chemistry panel tells your veterinarian about kidney and liver health, electrolyte levels, blood glucose levels and protein levels.
- Elevations in blood urea nitrogen (BUN) and creatinine may indicate kidney disease or may also be elevated in dehydrated pets.
- One liver value (alkaline phosphatase) is commonly elevated in older pets as a normal result of the aging process. Elevations in alkaline phosphatase may also be seen in pets who have been taking oral steroids, pets with liver or bone disease and young, growing pets. Alanine transaminase (ALT) is a liver value that, when elevated, can indicate ongoing liver damage.
- Glucose levels are elevated in diabetic patients. Occasionally, glucose is mildly elevated due to stress.
- Total protein levels are decreased in animals with poor nutrition or diseases that lead to protein loss, such as kidney or intestinal disease. Protein levels are elevated in dehydrated pets, those with some chronic infections and in some cases of leukemia.
- Electrolyte imbalances can be life threatening and may be due to a variety of conditions, from vomiting to endocrine diseases to intestinal parasites.
Baseline thyroid levels will let your veterinarian know if your pet has an underlying thyroid condition. Older cats are prone to overactive thyroids (hyperthyroidism), while older dogs have the opposite problem -- sluggish thyroids, which lead to hypothyroidism.
Senior pets should have blood work performed at least once a year and when they are battling systemic illness. Obtaining baseline levels will help your veterinarian stay on top of changes and prevent you both from being behind the eight ball should an illness arise.