For most blood work that requires fasting, you typically need to fast for 8 to 12 hours before the test. During this fasting period, you should not eat or drink anything except plain water. The purpose of fasting is to get a baseline measurement unaffected by recent food or drink intake. However, the exact fasting time may vary depending on the specific blood test your doctor has ordered, so following your healthcare provider's instructions is important. Some blood tests do not require fasting at all. Common tests that often need fasting include those measuring blood glucose, cholesterol, and triglycerides. Drinking water is usually allowed and even encouraged during fasting to keep hydrated, but you should avoid all other liquids, gum, smoking, and exercise. Scheduling the test early in the morning can make fasting easier as much of the time is spent sleeping. In summary:

• Typical fasting duration: 8-12 hours
• Drink only water during fasting
• Follow your doctor's specific instructions for your test
• Some tests do not need fasting
• Morning appointments are recommended to minimize discomfort

This guidance ensures the most accurate blood test results by minimizing the impact of recent food or drink intake on your blood composition.