how long can you not eat for a blood test CBC
Fasting. If you are required to fast prior to your blood test, your doctor's office will provide you with specific instructions. Most cholesterol and triglyceride blood tests require that you fast for 12 hours prior to your test.If you are having your glucose levels or vitamin levels checked, you will need to fast for at least eight hours prior to your test.asting is also not likely required for a blood test that determines your blood counts -- such as a complete blood count, or CBC. The number of blood cells in your body stays the same regardless of whether or not you eat anything.