People frequently ask if "everything" is tested with lab work. Unfortunately, no. If so, all we (or human physicians) would ever need to do is collect some blood to get a diagnosis. Think of it this way...if you were trying to put together a 100 piece puzzle (without the cover picture!) and you received 3 or 4 pieces, you would have very little information to go by. If you received pieces with a football-shaped eye featuring an up-and-down pupil, a set of whiskers, and a triangular nose, you would have an idea that the picture was of a cat. If you then got a couple triangular ears, a kitty mouth, and some fur, you would be on your way to completion. Baseline lab work is like puzzle pieces. It helps with the big picture but does not tell you everything. Sometimes, x-rays, ultrasound, special lab tests, and other tests need to be performed to obtain more puzzle pieces to help the doctor figure out the big picture.
Another common question is if lab work tests for cancer. We do not have the luxury of having a "cancer test" that can be run. Sometimes the CBC will reveal abnormal cells that alert us to certain types of cancer such as leukemia. There are a few blood values that could lean in the general direction of cancer, but they do not give an absolute answer. Generally, if other problems can be ruled out (problems with kidneys, liver, heart, thyroid, etc.) and there are significant problems (severe weight loss, vomiting, diarrhea, etc.), cancer may be suspected, and a hunt for further answers is conducted.
From our laboratory: 4 common questions about blood work and your pet
For information on urine tests, see our Urinalysis Page.
For information on blood pressure measurement, see our Blood Pressure Measurement Page.