Did your veterinarian ever suggest blood screening tests before upcoming anesthesia or elective surgery? Did your pet ever have a fever and your vet say, "We really should run a CBC (complete blood count) to see if your pet has an active infection"? Some times we hesitate to spend the extra money because animals look pretty good on the outside. In reality, since our patients can't tell us where they are hurting and often appear very normal in the office, blood screening may be the only early clue to an illness.
Complete blood counts are more than just counting the number of cells in a blood sample. This is usually the first window the inner workings of the body. These cells are in intimate contact with all the body organs. We can look at the number and appearance of each type of blood cell: WBC (white blood cells: increase during infection and inflammation); EOSINOPHILS:increase in response to allergies and parasites; RBC (red blood cells: decrease during anemia thus reducing oxygen in cells. A CBC is very important to decide if a fever is do to infection or inflammation or maybe both. We can also determine the prognosis or probable outcome of a condition and if our treatment is working by repeating the CBC.
Blood chemistry tests are also very useful. Each test allows us to look at how a body organ is working. Since kidneys and the liver help to clear anesthetics and poisons, it is necessary to know if they are working well. Increased glucose in the blood can point to certain diseases. For example, last month a cat came into the office to have a dental cleaning. "Mittens" had a poor hair coat and had been losing a little weight. We thought that her teeth were bothering her. We checked her blood and found her blood glucose to be over 400 mg/dl. Normal is around 100 mg/dl. We postponed the dentistry and checked her urine. Sure enough, the urine had over 2000 mg of glucose in it. Normal cats do not have glucose in the urine. Now "Mitten's" owner is giving her insulin injections. Once she is stable, we will be able to anesthetize her safely and clean her teeth.
Similar situations happen every day. "Tippy" a 14 year old dog wasn't acting quite like herself. We tested her blood and found that one of the enzymes released from her liver was over 10 times normal. After further testing, we found that "Tippy" had a brain tumor that was causing her adrenal gland to make too much Cortisone. "Tippy" started on treatment and is now doing very well at 14 years old. Her owners report that she is more lively than she had been in several years.
Blood screening in young patients is also a good idea. This type of testing gives a baseline for the future. In addition, it could reveal an underlying problem that may have been present since birth. We once diagnosed a hereditary kidney disease in a kitten by blood testing before a elective spay.
Blood testing, chest x-rays, and urinalysis is very important when dealing with patients that can't tell you how they really feel. Screen testing is a win-win situation. Your pet has the best possible chance of having an optimal outcome from an elective procedure or recovering from illness, you have peace of mind, and your veterinarian will have all the information needed to give the best care possible to your pet.
It is no surprise that premature judgments and guessing can result in "shot gun" treatment and missing the diagnosis completely. A small amount of blood gives us a huge amount of information about a patient's physical condition.
Mark W. Richards, MS, PhD, DVM