You typically need to fast for 8 to 12 hours before having blood work done. During this fasting period, you should not eat or drink anything except water. This fasting helps ensure accurate test results by preventing recent food or drink from affecting the levels of substances like sugar, fats, and proteins in your blood

. Additional important points include:

• You can drink plain water during the fast, which helps keep you hydrated and makes blood drawing easier

• Avoid smoking, chewing gum, and exercising during the fasting period as these can affect digestion and test results

• Do not consume alcohol for at least 24 hours before the test if instructed

• Most people schedule their blood test early in the morning so that much of the fasting happens overnight while sleeping

• Fasting longer than 16 hours is generally not recommended as it can also affect results

• Always follow your healthcare provider’s specific instructions, as fasting requirements can vary depending on the particular blood test

In summary, the standard fasting duration before blood work is 8 to 12 hours with only water allowed during this time, but confirm with your doctor for your specific test.