Key Takeaways
- Some blood tests need you to fast first. The clinician or business that requested the test will tell you.
- Drinking water is usually fine, even while fasting, and makes veins easier to find.
- Wear sleeves that roll up easily above the elbow.
- Tell the phlebotomist about any medicines, supplements or allergies before the draw.
Why Preparation Matters
The draw itself takes a few minutes, but how you prepare can affect both the sample and how easy the draw is. Good preparation lowers the chance of a damaged sample or a difficult draw, and makes the visit more comfortable, whether blood is taken at a surgery, a clinic or at home.
Step 1: Check Whether You Need to Fast
Fasting means having nothing but water for a set time before the test. It is only needed when the test measures something that food changes, such as glucose or triglycerides. Many common tests, including a full blood count, do not need fasting. If nobody has told you, ask whoever requested the test. For more, see can you eat before a blood test.
Step 2: Drink Water
When you are dehydrated, veins are harder to find, which can mean more than one attempt. Unless you have been told otherwise, drink some water in the hours before the appointment. Alcohol the day before can change some results, so it is worth avoiding.
Step 3: Tell the Phlebotomist What You Take
Tell the phlebotomist about any medicines, vitamins and supplements you take. Some supplements can interfere with laboratory tests. Do not stop taking anything before a test unless the clinician who requested it has told you to.
Step 4: Wear the Right Clothing
Blood is usually taken from the inner crease of the elbow. Wear short sleeves, or sleeves loose enough to roll up above the elbow. A tight sleeve bunched around the upper arm can act like a tourniquet.
Step 5: If You Are Anxious About Needles
Fear of needles is common and nothing to be embarrassed about. Things that help many people:
- Tell the phlebotomist — they can talk you through it, go at your pace, or have you lie down.
- Look away — you do not need to watch.
- Tense your leg muscles — if you tend to feel faint, repeatedly tensing and relaxing the large muscles in your legs can help.
- Slow breathing — slow, steady breaths can calm the body's stress response.
See also our guide to needle phobia and blood tests.
On the Day
The phlebotomist will confirm who you are, check which tests have been requested, and ask about allergies such as latex. They put a tourniquet on your upper arm, clean the skin, and collect blood into one or more tubes. Afterwards, a pad or plaster goes on. Keep it on for a while and avoid heavy lifting with that arm for the rest of the day to reduce bruising.
After the Test
If you fasted, have something to eat ready. If you feel light-headed, sit down for a few minutes. Your samples go to a laboratory, and results go back to whoever requested the test.
Booking blood draws for your patients?
Lola Dispatch is an invitation-only platform healthcare businesses use to book mobile blood draws with approved phlebotomists. It does not take bookings from the public.