For a blood test that requires fasting, the general recommendation is to fast for 8 to 12 hours before the test. During this time, you should avoid all food and drinks except water to ensure accurate test results. Some tests might require slightly longer fasting, up to about 14 hours for things like lipid panels. It is usually advised to do the fasting overnight with the blood draw scheduled in the morning. If there are any specific instructions given by your doctor regarding the fasting duration or medication intake, those should be followed precisely. Also, drinking plenty of water before the test is recommended. If you have conditions like diabetes, you should consult your doctor about how to safely fast. In summary:

• Typical fasting time: 8 to 12 hours
• Only water is allowed during fasting
• Some tests may require up to 14 hours fasting
• Follow your doctor’s specific instructions
• Drink plenty of water before the test

This approach helps to get reliable baseline blood test results unaffected by recent food or drink intake.