Following your doctor’s instructions is the most important part of preparing for a blood test. Sleeping well, staying hydrated, and avoiding certain foods and drinks can also provide benefits.

Blood tests are a common procedure, but many people may feel nervous about having blood drawn. Others may be unsure how to prepare or whether to avoid eating or drinking beforehand.

This article provides tips that can help you prepare for a blood test and explains what you can expect during a blood draw procedure.

Here are preparation tips you can follow the day before your blood test:

  • Check your doctor’s instructions carefully. For certain blood tests, you may need to fast (avoid eating or drinking anything except water) for 9–12 hours beforehand. Your doctor may also ask you to stop taking certain prescription medications.
  • If you need to fast, also consider avoiding activities like smoking, drinking alcohol, chewing gum, and doing strenuous exercise. These can all affect blood test results.
  • If you don’t need to fast, consider avoiding alcohol and fatty or rich foods. This will ensure you feel your best the day of the appointment.
  • Get plenty of sleep. Being well-rested helps make your veins easier to access during the blood draw.
  • If you’re going to a lab that doesn’t require appointments, call ahead to find out when they’re least busy to avoid a long wait.
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Here are preparation tips you can follow on the day of your blood test:

  • Drink plenty of water. Staying hydrated keeps more fluid in your veins, making the blood draw easier.
  • Avoid coffee and other caffeinated drinks, which may dehydrate you.
  • If you don’t need to fast, eat breakfast 1–2 hours before the test. This can help prevent lightheadedness during the blood draw.
  • If you’re concerned about queasiness or nausea, avoid eating right before your appointment.
  • Wear short sleeves beneath any outerwear to make it easier to access your arm.
  • Arrive several minutes early so that you have time to fill out any paperwork.
  • Bring your insurance card and identification.
  • Bring a small snack, such as fruit or a protein bar, for after your appointment.

A blood draw is a quick procedure that usually takes only a few minutes.

When you arrive at the lab, you’ll check in for your appointment at the front desk. You’ll wait in the lobby until a technician calls you into the blood draw room. The technician will have you sit in a chair with an armrest.

If you’re wearing a long-sleeve shirt, you’ll roll up your sleeve past your elbow. Then you’ll stretch your arm out in front of you.

The technician will clean a small area on your arm with an antiseptic wipe. They’ll also tie an elastic band around your arm. This causes your vein to swell, making it easier to insert a needle and draw blood.

To encourage blood flow, the technician may ask you to make a fist. Then, they’ll gently insert a needle into your arm. You may feel a slight pricking sensation, but it shouldn’t be painful.

Once enough blood has been drawn, the technician will remove the needle and place a small bandage over the area.

Let your technician know if you feel dizzy after your blood draw. You can remain in the chair until the dizziness passes. If you brought a snack and water, this would be a good time to consume it. If you did not bring any food or water with you, ask the technician for a cup of water. Drinking water can help reduce any dizziness you may be feeling.

You may have minor soreness or a small bruise on your arm where the needle went in. Any pain you experience should go away within a few days.

How to cope with nervousness

  • Tell the technician if you’re feeling nervous. They can help you feel more comfortable and discuss options such as lying down instead of sitting.
  • Avoid looking at the blood draw. Pick an object or another spot in the room to focus on.
  • Talk with the technician to help distract you during the procedure.
  • Listen to music on earbuds or headphones.
  • Take a few deep breaths before and during the procedure. Focus on each breath going in and out to keep your mind off the procedure.
  • Bring a friend to support and comfort you.
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For many common blood tests, you can expect to receive the results from 24 hours to a few days later. This includes:

In some cases, it may take up to a few weeks to get the results. For example, tests for rare conditions may take longer, since not every laboratory is equipped for specialized testing.

Speak with your doctor or laboratory technician to find out when you can expect the results from your test.

A blood test is a quick and common medical procedure. The best way to prepare for a blood test is to follow your doctor’s specific instructions. Certain blood tests may require fasting beforehand, but it depends on which test you’re having.

If you’re concerned you may feel nervous or queasy, let your technician know so they can help you feel more comfortable. Taking a few deep breaths or listening to music may help you relax.