You generally need to fast for 8 to 12 hours before blood work, depending on the specific test being done

. During this fasting period, you should avoid eating and drinking anything except water. You should also refrain from smoking, chewing gum, and exercising, as these can affect digestion and potentially skew test results

. Fasting ensures that your blood test results are accurate because food and drinks introduce sugars, fats, and other nutrients into your bloodstream, which can temporarily alter levels of substances measured by the test

. For example, fasting is especially important before tests measuring blood glucose, triglycerides, and iron levels

. Most people schedule fasting blood tests early in the morning so that the fasting period mostly occurs during sleep, making it easier to comply

. Drinking plain water during the fasting period is encouraged to stay hydrated and make veins easier to access for blood draws

. If you accidentally eat or drink anything besides water before the test, inform your healthcare provider, as it may require rescheduling or affect interpretation of results

. In summary:

• Fast for 8 to 12 hours before your blood test, as instructed by your healthcare provider.
• Only drink water during this time.
• Avoid smoking, gum, and exercise.
• Schedule tests in the morning if possible.
• Confirm fasting instructions with your provider since not all tests require fasting.

This approach helps provide the most accurate baseline measurements for your blood work