Tests that often require fasting: These tests measure things like blood glucose (sugar) and lipids (fats), which are significantly affected by recent food intake.
Tests that typically do *not* require fasting: Many blood tests, such as those checking for complete blood counts (CBC), liver function, kidney function, and many others, are not significantly impacted by recent food intake.
Therefore, it's crucial to discuss fasting requirements with your veterinarian *before* the blood test. They will know which tests are ordered and can advise you appropriately. They will tell you how long to fast your dog for, if fasting is necessary. Incorrect fasting instructions can affect test results.