Introduction to Phlebotomy

Phlebotomy is the practice of drawing blood for lab tests, transfusions or donations. A good phlebotomist is steady with a needle and steady with people, because a calm patient is easier to draw from. Doctors make decisions from your specimens, so small mistakes matter. This guide follows the venipuncture practices in the standards from the Clinical and Laboratory Standards Institute (CLSI). Your employer's procedure comes first, and most states and employers expect formal training or certification, with supervised practice on real patients. Reading this guide does not replace that.

What You Will Be Able to Do

• Pick the safest vein and avoid sites you must not use.
• Choose the right needle and collection system.
• Identify the patient and explain the draw.
• Perform a venipuncture step by step.
• Recognize and respond to hematoma, nerve injury and fainting.
• Adjust your approach for children, older adults and people on blood thinners.

Anatomy of the Antecubital Fossa

The antecubital fossa (the inside of the elbow) is the primary venipuncture site because the veins there are typically large, accessible, and well-anchored. Understanding the anatomy helps you choose the safest vein.

Three Primary Veins

1. Median cubital vein - The preferred vein for venipuncture. It runs diagonally across the antecubital fossa, connecting the cephalic and basilic veins. It is usually large, well-anchored to surrounding tissue (which means it does not roll easily), and is not positioned near major nerves or arteries.

2. Cephalic vein - Located on the lateral (outer/thumb) side of the arm. It is a good second choice. It tends to roll more than the median cubital, so you need to anchor it firmly. It is generally safe because major nerves and arteries are not nearby.

3. Basilic vein - Located on the medial (inner/pinky) side of the arm. Use this as a last resort in the antecubital area because the brachial artery and median nerve run close to this vein. Accidental puncture of the artery or nerve can cause serious complications.

Alternative Sites

When no suitable antecubital vein is available:

• Dorsal hand veins - Veins on the back of the hand. Use a butterfly (winged infusion) needle. These veins are smaller and more painful to puncture, but they are often visible and accessible.
• Forearm veins - Veins on the anterior forearm can sometimes be used, though they tend to be deeper and less well-anchored.
• Never draw from - Do not draw from an arm with an IV line (results will be contaminated), an arm on the side of a mastectomy (risk of lymphedema), an AV fistula or graft used for dialysis (unless specifically authorized), or an area with burns, scarring, or hematoma.

Equipment and Supplies

Collection Systems

Two primary collection systems are used in phlebotomy:

Evacuated tube system (ETS) - The most common method. Consists of a double-pointed needle, a plastic tube holder, and evacuated (vacuum) collection tubes. The vacuum in the tube draws blood automatically when the tube is pushed onto the needle inside the holder.

Syringe system - Uses a needle attached to a syringe. The phlebotomist manually pulls back the plunger to draw blood, then transfers it to collection tubes. Used for fragile veins where the vacuum of the ETS might collapse the vein.

Butterfly (winged infusion) set - A small needle with flexible wings and tubing that connects to either an ETS holder or a syringe. Ideal for hand veins, pediatric draws, elderly patients with fragile veins, and difficult access situations.

Needle Gauges

• 21 gauge - Standard for most adult venipuncture. Good flow rate, minimal hemolysis.
• 22 gauge - Used for smaller veins or patients with fragile veins. Slightly higher risk of hemolysis.
• 23 gauge - Butterfly needle gauge for very small veins (hand veins, pediatric patients). Higher hemolysis risk.
• Lower gauge numbers = larger needle diameter. A 21-gauge needle is larger than a 23-gauge needle.

Collection Tubes

Evacuated tubes have color-coded stoppers that show the additive inside. Tubes must be filled in a set order, and they must be mixed, labeled and transported correctly. Learn the colors and the order of draw before your first patient.

Other Essential Supplies

• Tourniquet - Flat latex-free band. Single-use disposable tourniquets are preferred for infection control.
• Alcohol prep pads - 70% isopropyl alcohol for site disinfection.
• Povidone-iodine pads - Used for blood culture collection (or chlorhexidine per facility protocol).
• Gauze pads (2x2) - For post-draw pressure.
• Adhesive bandages or coban wrap - To secure gauze after the draw.
• Sharps container - For immediate needle disposal. Must be within arm's reach during the procedure.
• Gloves - A fresh pair for every patient. Non-latex options must be available.
• Labels - Pre-printed or handwritten with patient name, date of birth, date, time, and collector's initials.

Patient Identification and Communication

Two Identifiers

Identifying the patient correctly is a core safety requirement. The Joint Commission calls for at least two identifiers. Before any blood draw:

1. Ask the patient to state their full legal name
2. Ask the patient to state their date of birth
3. Compare both identifiers to the requisition form
4. Compare to the patient's wristband (inpatient settings)
5. Do not draw blood from any patient you cannot positively identify using two independent identifiers

Never identify a patient by asking "Are you John Smith?" The patient may be confused, hard of hearing, or simply agree. Always use open-ended questions: "Can you tell me your full name?"

Patient Communication

Good communication reduces anxiety, increases cooperation, and leads to better outcomes:

• Introduce yourself by name and role: "Good morning, my name is [name] and I am a phlebotomist from the laboratory."
• Explain the procedure briefly: "I need to draw some blood for tests that your doctor ordered."
• Ask about previous experiences: "Have you had any problems with blood draws in the past?"
• Ask about allergies to latex, adhesive tape, or iodine
• Let the patient know when you are about to insert the needle: "You will feel a small stick now."
• If the patient is anxious, reassure them and give them a moment. Suggest they look away.
• Never tell a patient "this won't hurt." Be honest: "You will feel a brief pinch."

Informed Consent and Right to Refuse

Patients have the right to refuse a blood draw. If a patient refuses:

1. Explain why the test was ordered and that the physician requested it
2. Do not force or threaten the patient
3. Document the refusal and notify the ordering physician or nurse
4. Follow your facility's refusal protocol

Performing the Venipuncture

Pre-Procedure Checklist

Before approaching the patient, verify:

• Requisition form matches patient identification
• You have all required tubes and supplies
• You understand any special collection requirements (fasting, timed draw, chilled specimen)
• Gloves are on
• Sharps container is accessible

Step-by-Step Procedure

1. Position the patient - The patient should be seated in a phlebotomy chair with an armrest, or lying in bed with the arm supported. Never draw blood from a standing patient (risk of syncope and fall). Extend the arm with a slight downward angle.

2. Apply the tourniquet - Place it 3 to 4 inches (about one hand-width) above the intended puncture site. The tourniquet should be tight enough to restrict venous blood flow but not so tight that it occludes arterial flow. You should still feel a radial pulse. Ask the patient to make a gentle fist (do not pump the fist, as this can alter potassium levels).

3. Select the vein - Palpate with your index finger. A good vein feels spongy, bouncy, and resilient. It refills when you press and release. An artery will feel like it is pulsing. A tendon feels hard, cord-like, and does not bounce. Do not select a vein that feels hard or cord-like (may be scarred or thrombosed).

4. Release the tourniquet while you prepare your equipment if more than one minute will pass. Prolonged tourniquet application (over 1 minute) can alter lab results by concentrating blood components (hemoconcentration).

5. Clean the site - Scrub the puncture site with a 70% isopropyl alcohol prep pad using a firm, circular motion from the center outward. Allow the site to air dry completely (approximately 30 seconds). Do not blow on it, fan it, or touch it after cleaning.

6. Reapply the tourniquet - If you released it during preparation.

7. Anchor the vein - With your non-dominant hand, use your thumb to pull the skin taut 1 to 2 inches below the puncture site. This anchors the vein and prevents it from rolling.

8. Insert the needle - With the bevel (the angled opening) facing up, insert the needle at a 15 to 30 degree angle in the direction of blood flow (toward the hand). Use a smooth, controlled motion. You will feel a slight "pop" or "give" when the needle enters the vein.

9. Engage the first tube - Push the collection tube onto the needle inside the holder. The vacuum will draw blood into the tube. Hold the holder steady - do not push or pull on the needle.

10. Fill tubes in the correct order - When the first tube stops filling, remove it with a gentle twist and push the next tube on. Gently invert additive tubes as soon as you remove them, so that the additive mixes with the blood. Do not shake.

11. Release the tourniquet - Always release the tourniquet before removing the needle. Removing the needle with the tourniquet in place increases the risk of hematoma.

12. Remove the needle - Place a folded gauze pad over the puncture site (without pressing yet), then withdraw the needle smoothly at the same angle it was inserted. Immediately activate the needle's safety device.

13. Apply pressure - Press the gauze firmly over the site. Have the patient hold firm, direct pressure for about 3 to 5 minutes, and at least 5 minutes for patients on anticoagulants or aspirin. Do not let the patient bend their arm - this is a common mistake that increases hematoma formation.

14. Dispose of the needle - Immediately place the needle and holder in the sharps container. Never recap a needle.

15. Label tubes at the bedside - Label every tube while still with the patient. Each label must include the patient's full name, date of birth, medical record number (if applicable), date and time of collection, and your initials. Never pre-label tubes before the draw.

16. Check the patient - Remove the gauze and inspect the site. Apply an adhesive bandage. Ask the patient how they feel before allowing them to leave.

Common Complications and How to Handle Them

Hematoma

A bruise caused by blood leaking into the surrounding tissue. Causes include: through-and-through puncture of the vein, needle bevel only partially in the vein, excessive probing, removing the needle before releasing the tourniquet, or insufficient pressure after the draw. If you see swelling during the draw, immediately release the tourniquet, remove the needle, and apply firm pressure for 5 minutes.

Hemolysis

The rupture of red blood cells, causing serum or plasma to turn pink or red. This invalidates many test results. Causes include: using too small a needle, pulling a syringe plunger back too forcefully, shaking tubes instead of gently inverting, forcing blood through a small needle into a tube, or drawing from a hematoma. Prevention: use the largest appropriate gauge needle, use gentle technique, and invert tubes slowly.

Nerve Injury

If the patient reports sharp, shooting, electrical, or radiating pain at any point during the procedure, remove the needle immediately. This may indicate you have contacted a nerve. Do not redirect the needle. Apologize, apply pressure, and attempt the draw at a different site. Document the incident per your facility's policy.

Syncope (Fainting)

Some patients faint during or after blood draws. Warning signs include pallor, sweating, lightheadedness, nausea, and tunnel vision. If a patient feels dizzy or faint, stop the draw, release the tourniquet and remove the needle first.

• If the patient is in a chair, lower the head between the knees or recline the chair
• If the patient loses consciousness, lower them to the floor safely, elevate their legs, and loosen tight clothing
• Apply a cold compress to the forehead or back of the neck
• Never leave a patient who reports feeling faint unattended
• Some facilities require a post-draw observation period for patients who have a history of syncope

Petechiae

Small red dots that appear after prolonged tourniquet application. Prevent by limiting tourniquet time to one minute. If petechiae develop, release the tourniquet immediately.

Failure to Obtain Blood

If blood does not flow into the tube:

1. Make sure the tube has vacuum - try a new tube
2. Gently rotate the needle a quarter turn (the bevel may be against the vein wall)
3. Pull back slightly (you may have gone through the vein)
4. Advance slightly (you may not be fully in the vein)
5. If still unsuccessful, remove the needle and try a different site
6. Do not probe or redirect more than twice on a single insertion. Limit total attempts to two per phlebotomist. If unsuccessful after two attempts, ask a colleague or supervisor for help.

Infection Control

Wear gloves for every draw, change them between patients and clean your hands before and after. Use safety-engineered needles, activate the safety feature right away and put sharps straight into a puncture-resistant sharps container. Never recap a used needle by hand.

If you get a needlestick, wash the area with soap and water, report it to your supervisor immediately and get a medical evaluation right away. Treatment after an exposure works best when started quickly.

Special Populations

Pediatric Patients

• Use butterfly needles and smaller collection tubes (microtainers) for infants
• Capillary (heel stick or finger stick) collection is preferred for infants under 6 months. For any patient, it also suits tests that need only a small volume, such as a glucose check
• For heel sticks, warm the heel for 3-5 minutes, puncture the medial or lateral plantar surface (not the center, to avoid bone), and use a lancet with a depth appropriate for the infant's size
• Have a parent or assistant help hold the child. Distraction techniques (singing, bubbles, tablets) can help.
• Collect only the minimum volume needed for testing

Geriatric Patients

• Veins are often fragile, thin-walled, and prone to rolling
• Use a smaller gauge needle (22 or 23) or a butterfly
• Apply the tourniquet loosely to avoid tearing fragile skin
• Anchor the vein very firmly as rolling veins are common
• Apply pressure for longer after the draw as bruising is more likely
• Be patient and communicate clearly, as hearing or cognitive impairment may be present

Patients on Anticoagulants

• Patients taking warfarin, heparin, aspirin, or newer anticoagulants (apixaban, rivaroxaban) bleed longer
• Apply pressure for at least 5 minutes after the draw
• Do not use adhesive bandages alone - use gauze with a pressure wrap
• Document the anticoagulant use

Common Mistakes

Check Your Understanding

1. A patient has an IV running in her left arm and had a mastectomy on the right side. What do you do?

Do not choose a site on your own. Ask the nurse, and follow your facility's policy.

2. As you enter the vein, the patient says he feels an electric shock down his arm. What do you do?

Remove the needle immediately, apply pressure and choose a different site. Report and document it.

3. You miss twice. The patient says, "Go ahead and try again." What do you do?

Stop and ask another qualified phlebotomist to try.

4. A patient on warfarin has finished his draw. How long should pressure be held?

At least 5 minutes, and check that the bleeding has stopped before you apply the bandage.

Key Takeaways

• Verify identity with two identifiers before any draw.
• The median cubital vein is the first choice, and the basilic is the last in that area.
• Limit tourniquet time to 1 minute, and do not have the patient pump a fist.
• Use a 15 to 30 degree angle, with the bevel up.
• Remove the tourniquet before the needle.
• Stop right away for shooting pain, and ask for help after two failed attempts.