Pet points: Tests help determine what ails a pet
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Pets are good communicators.
Dogs wake us up before the alarm. They let us know when it is dinner time and when they need to go out. They announce when the mail and UPS deliveries come to the door. Some dogs let you know when a spouse is home minutes before he or she walks in the door.
Cats let you know when the litter box needs to be cleaned (one way or another), and intelligent cats will know when it is time for attention, with both giving and getting affection. But when pet parents bring them in for a veterinary exam, they clam up.
As veterinarians we often have to rely on laboratory tests to prove that our patients are well or sick. Some basic tests like a fecal exam or a urinalysis are commonly done for both routine and sick patients.
Blood work is often necessary for us to learn the status of our patients. We routinely do a complete blood count (CBC) and a comprehensive chemistry to aid us in making a diagnosis. It is now also common for veterinarians to recommend a CBC and chemistry prior to any anesthesia. Making anesthesia safer is our goal by finding problems before they are obvious. Even young apparently healthy pets can have serious health problems detected with blood tests. Senior pets, older that 8 years depending on breed, are advised to have blood testing to promote early detection of problems and to establish a baseline for older pets.
The CBC will let us know if anemia is a problem. Likewise it helps us know if dehydration is an issue. Low white blood cell counts are frequently seen in a puppy suffering from parvo virus. Panleukopenia in cats will show alterations in the white blood cells. Panleukopenia is cat distemper, and it is now rare due to vaccination programs. Other infections can be detected by an increase in the number of the white blood cells. If a pet has a uterus infection, the white blood cell count can triple. We even find pets with life-threatening leukemia, a cancer found with the blood test.
The chemistry values will tell us the information on how the internal organs are functioning. Kidney health is followed by checking the Blood Urea Nitrogen, the amount of nitrogen waste in the blood that is normally excreted by the kidney. Creatinine also gives us a score of renal function that can be described on a scale from 1 to 10. Anything above 2 can be a sign of kidney trouble.
Liver values are checked and elevations can be a sign of of issues in this important organ, which can fail and cause consequences, including jaundice and death. The liver is vital in removing toxins and produces bile for digestion. The liver has many other life-sustaining functions, such as proper blood clotting.
Both the pancreas and adrenal gland are also evaluated with a chemistry. Pancreatitis is a serious disease seen in vomiting patients and is checked when we run a blood sample. An over-functioning adrenal gland causes Cushing's disease and is seen in older dogs with liver enzyme elevations that can be followed over time. Addison's disease, seen when the adrenal gland malfunctions, can be fatal if not diagnosed. The electrolytes in a blood sample give us clues for this serious problem.
Glucose is important to check to see if it is low in sick and seizing dogs. We often diagnose diabetes in dogs and cats with high glucose readings, even when the owner was not aware of the classic symptoms of drinking more water.
Animals on chronic medications, including seizure and pain control, must have periodic blood test evaluation to make sure that medications are not interfering with normal organ function.
Thyroid testing for older cats will look for elevations that are common. Hyperthyroid (high-thyroid) cats will lose weight in spite of having an excessive appetite. Treatment options can be discussed once the diagnosis is made. Hypothyroid (low-thyroid) conditions in dogs can be corrected with supplementation. Low thyroid can cause obesity, heat seeking and poor hair coats.
Blood work alone is not the sole way to clear a pet from being ill. I recently had a dog with inoperable cancer that had perfectly normal blood tests. Experience and additional testing using radiographs were necessary to convince me that an exploratory surgery was necessary in this case.
Many veterinarians provide in-office testing. When these testing capabilities are combined with an outside laboratory that pick up samples once or twice a day, veterinarians can get results in minutes, the same day or overnight.
Although blood testing can increase the cost of veterinary care, these results are invaluable in helping veterinarians access the health of our patients. Now, if we could only teach a pet to tell us where it hurts.
First Published January 26, 2013 12:00 am