How to Fast for Blood Chemistry Screening

A blood chemistry screening, sometimes called a basic metabolic panel, measures the level of various chemicals and substances in your blood. Potassium, creatinine, calcium and glucose, are just a few of the things a blood chemistry screening evaluates. From these levels, your doctor can determine the functioning health of vital organs such as your kidneys, heart, liver and pancreas. To obtain a baseline sample, untainted by your most recent meal, your doctor will typically ask you to fast for 8 hours, prior to your test.

Instructions

• 1

  Eat before beginning your fasting period. Consume a sizable, but healthy meal without a lot of fat, sugar or salt. A low-fat turkey sandwich with some fruit and yogurt is good.

• 2

  Drink water regularly. Once your fast begins, you may only drink plain water. Staying hydrated makes your blood easier to draw. Note that plain water means plain water, not clear, zero-calorie energy drinks, tea, coffee or milk.

• 3

  Stop consuming all foods while fasting. Simply refuse to put anything to your lips besides water. Even foods you may not think of as "food" like chewing gum, mints or cough drops can affect the results of your blood chemistry test.