How to prepare for bloodwork

Your doctor may recommend bloodwork as part of a routine checkup or for other medical reasons. Blood tests can show signs of infection, immune system problems, or deficiencies in vitamins and minerals. They can also let your doctor know if your organs are functioning correctly or if you have risk factors for certain diseases.

A complete blood count (CBC) is typically part of a routine checkup and gives your doctor a look at your overall health. Your doctor may also use it to screen for potential problems if you’re sick.

Other blood tests give doctors information about specific organs. They include your heart, bones, kidneys, and liver. Your doctor can also check your cholesterol levels and blood sugar from specific blood tests.

Before going to your bloodwork appointment, you can do a few things to prepare for a blood test.

Do I Need to Fast Before a Blood Test?

Your doctor’s office will give you specific instructions on how to prepare for a blood test. For some tests, you don’t need to do anything special. You can eat and drink as you normally would.

For other tests, like blood glucose or cholesterol, you will need to fast (not eat any food) for eight to 12 hours. Your doctor will tell you exactly how long to fast before blood work.

If you need to fast, your test will likely be early in the morning. That way most of your fasting will take place overnight. A typical fasting period is 12 hours, allowing you start to fast from, say, 8 p.m. the night for an 8 a.m. test.

When you’re fasting, you should continue to drink water to stay hydrated. Keeping more fluid in your veins also makes it easier to draw blood.

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What Should I Do Before a Blood Test to Make It Easier?

Your doctor’s office will give you instructions about where to go for your bloodwork. The lab may be in the same building as your doctor’s office. Or it could be in a nearby medical center or hospital.

To prepare for a blood test:

  • Follow the doctor’s instructions about how long to fast — if you need to — before your appointment.
  • Continue to drink water.
  • Continue taking any prescribed medication, unless your doctor tells you not to. You may have to avoid medication that’s usually taken with food. Check with your doctor before taking any over-the-counter supplements or vitamins.
  • Wear a short-sleeved shirt, or one with sleeves that roll up easily, to allow access to your upper arm.
  • Arrive a few minutes early in case you need to fill out paperwork.
  • If you didn’t follow the instructions exactly, let someone know right away. Your test results probably won’t be accurate, and you may need to reschedule your appointment.

What Not to Do Before Blood Work

If your doctor tells you to fast before a blood test, you should avoid these things as well. Don’t:

  • Drink anything other than water. That includes soda, coffee, and juice.
  • Smoke. Nicotine can stimulate the digestive system and throw off test results.
  • Chew gum. Chewing gum can also speed up your digestion, affecting test results.
  • Consume alcohol. Alcohol can raise your liver enzymes and blood sugar, affecting blood test results.
  • Work out. Strenuous exercise can result in higher glucose readings on a blood test.

Tips to Relax

Some people find bloodwork appointments stressful. They may be afraid of needles, or uncomfortable at the sight of their own blood. But there are some ways to reduce your anxiety when having blood drawn.

  • Bring a friend along. Talking while you’re having blood drawn is a good distraction.
  • Listen to music on headphones.
  • Try deep breathing techniques. Focusing on each breath will take your mind off the blood draw.
  • Tell the phlebotomist (the person who draws the blood) that you’re nervous. They see many people who are anxious about needles and blood, and they can help you calm down.
  • Look away when the phlebotomist begins to draw your blood.

Remember that having a blood test is relatively painless, and it only takes a few minutes. If you have any questions about preparing for a blood test, ask your doctor.

UPMC offers full-service lab work at all of our convenient outpatient locations. To find a location near you, visit

NHS, Blood Tests, Link

National Heart, Lung, and Blood Institute, Blood Tests, Link

National Library of Medicine, How to Prepare for a Lab Test, Link

National Library of Medicine, Fasting for a Blood Test, Link

American Academy of Family Physicians, Complete Blood Count (CBC), Link

About UPMC

Headquartered in Pittsburgh, UPMC is a world-renowned health care provider and insurer. We operate 40 hospitals and 800 doctors’ offices and outpatient centers, with locations throughout Pennsylvania, Maryland, New York, West Virginia, and internationally. We employ 4,900 physicians, and we are leaders in clinical care, groundbreaking research, and treatment breakthroughs. U.S. News & World Report consistently ranks UPMC Presbyterian Shadyside as one of the nation’s best hospitals in many specialties and ranks UPMC Children’s Hospital of Pittsburgh on its Honor Roll of America’s Best Children’s Hospitals. We are dedicated to providing Life Changing Medicine to our communities.