Tumor marker tests do not require fasting and are usually accurate when done after eating breakfast. Tumor markers refer to alpha-fetoprotein, carcinoembryonic antigen, CA199, CA125 and so on, which can indicate digestive tract tumors, ovarian cancer and so on. Tumor marker tests do not require fasting blood draws, so the test can be done after meals as well, which has no effect on the test values, but try to have a low-fat diet before the test to avoid lipids interfering with serum extraction. As an important means of tumor screening, serum tumor marker is less traumatic and has been generally accepted. There are many testing items, so you can choose the appropriate items according to your personal situation, which can play an early warning role.