Even pets that appear completely healthy can have hidden health problems. If left undetected, these problems can lead into serious, even life-threatening conditions. Blood tests are essential tools for identifying diseases at the earliest stage possible, when they are the most treatable. Blood tests can be used to detect, treat and prevent potentially dangerous illnesses. Sick or older animals often have more than once disease process affecting them at the same time, complicating diagnosis and treatment. Blood tests can help pinpoint specific problems. In addition, some medications can be harmful if your pet has certain underlying problems, such as kidney or liver disease. In such cases, your veterinarian may order blood tests to make sure your pet is healthy enough to take the medication. Finally, even in young and healthy pets, laboratory testing helps your veterinarian establish a baseline picture of what represents good health for your individual pet. This is why blood tests are recommended as part of your pet’s annual physical examination.