The general recommendation for fasting before a blood test is to fast for 8 to 12 hours. This means no food or drinks except water during that time. Fasting is important for tests that measure blood glucose, triglycerides, and iron levels, as eating before the test can affect the accuracy of these results. Drinking water is usually allowed and encouraged to keep hydrated. Some tests do not require fasting, so it is best to follow specific instructions provided by the healthcare provider. In summary:

• Fast for 8 to 12 hours before the blood test.
• Drink only water during the fast.
• Avoid smoking, gum, and exercise before the test.
• Follow your doctor's instructions if any adjustments are needed.

This fasting period ensures more accurate blood test results, especially for glucose, lipid panels, and anemia testing.