Rules on How to Fast for Blood Work

Blood tests that check sugar or cholesterol levels must be performed only after a patient has fasted. Fasting allows a doctor to get an accurate blood result in order to make a diagnosis. If a patient doesn't follow fasting rules before a blood test, he will be asked to reschedule.

Instructions

• 1

  Make an appointment with your blood laboratory. Schedule a morning appointment if it is difficult for you to go without food for long periods.

• 2

  Determine the time to begin your fast. Count back 12 hours from the appointment time. For example, if your appointment is 7 a.m., 12 hours earlier is 7 p.m. This is the time you must begin fasting for your blood test.

• 3

  Drink only water after you begin the fast.

• 4

  Consult your physician if you are taking medication.

• 5

  Abstain from smoking, sucking on mints or chewing gum during your fast. You may resume these activities once your blood has been drawn.