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newSchoolWorks.com › VoTechWorks › Health & Personal Services › Phlebotomy Technician › Venipuncture: Technique, Safety, and Clinical Application › Lesson 8
HLT-PHLE88-02 · Lesson 8 · 5 clock hours · theory

Complications: Recognition, Prevention, and Response

Objective. Students will identify the signs of common venipuncture complications—including hematoma, hemolysis, nerve injury, syncope, and arterial puncture—and state the correct within-scope response for each.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed clinician in the field or by a certification or approval body. It is a study draft and may contain errors. Do not use it to make decisions about any patient or medication. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Why Complications Matter

Venipuncture is a routine procedure, but it carries real risks. Recognizing a complication early, responding correctly, and staying within your scope of practice protects the patient from harm and protects you professionally. Every phlebotomy technician must know the warning signs and the correct action for each common complication before performing draws independently.

Hematoma

A hematoma is a collection of blood that leaks into tissue surrounding the vein, producing a visible bruise or raised swelling at or near the puncture site. Common causes include: puncturing through the vein's posterior wall, removing the needle while the tourniquet is still applied, failing to apply adequate pressure after withdrawal, or using a vein that is fragile or small.

Prevention: Release the tourniquet before withdrawing the needle. Apply firm, continuous pressure for at least two to three minutes—longer for patients on anticoagulants. Avoid probing the needle laterally under the skin.

Response: Remove the needle immediately and apply direct pressure. Elevate the arm if the patient can tolerate it. Document the finding. Do not re-stick the same site. Inform your supervisor.

Hemolysis

Hemolysis is the rupturing of red blood cells, which releases hemoglobin into the sample and makes it appear pink or red. This ruins many lab tests. Causes include drawing too forcefully through a small-gauge needle, using a needle that is too small for the volume required, mixing tubes too vigorously, or transferring blood from a syringe into a tube with excessive force.

Prevention: Use an appropriate gauge needle, mix tubes gently by inversion (never shake), and fill tubes at a steady flow rate. Draw the correct order of draw to avoid cross-contamination.

Response: Label the specimen as hemolyzed and notify the nurse or ordering provider or your supervisor immediately. A recollection will usually be required. Document the incident.

Nerve Injury

Nerves run close to veins in the antecubital fossa and wrist. A nerve may be struck if the needle is inserted at the wrong angle, if the needle is redirected (probed) laterally, or if an anatomically unsuitable site is chosen.

Signs: The patient reports immediate, sharp, shooting, or electric pain radiating down the arm or into the fingers. This is different from the normal brief stick sensation.

Prevention: Do not redirect a needle laterally once it is under the skin. If you must adjust, withdraw completely and re-stick. Avoid blind sticking when a vein is not palpable.

Response: Remove the needle immediately. Do not continue the draw. Apply pressure. Report to your supervisor at once. Document the patient's complaint in detail. Never minimize or dismiss the patient's pain report.

Syncope (Fainting)

Syncope is the most common patient emergency in phlebotomy. It results from a vasovagal response: the patient's blood pressure drops suddenly, reducing blood flow to the brain. Risk factors include anxiety, fasting, pain, heat, and a history of fainting with blood draws.

Signs: Pallor (paleness), diaphoresis (sweating), dizziness, nausea, slurred speech, weakness, or loss of consciousness.

Prevention: Ask about prior fainting history before every draw. Have the patient lie down or sit in a phlebotomy chair with arm support if there is any concern. Keep the patient talking calmly.

Response (in scope):

1. Remove the needle immediately and apply pressure.

2. Call out for help or activate your facility's emergency alert system—do not leave the patient alone.

3. Lower the patient to a safe position: recline the chair fully or assist a seated patient to put their head between their knees. If the patient is already falling, guide them safely to the floor rather than trying to hold them upright.

4. Apply a cold, damp compress to the forehead or back of the neck.

5. Loosen any restrictive clothing.

6. Stay with the patient and monitor breathing and responsiveness until help arrives.

7. Document the event fully, including time, patient's condition, actions taken, and who was notified.

If the patient loses consciousness and you cannot rouse them, follow your facility's emergency protocol. Calling 911 or activating a code may be required—follow your supervisor's instructions.

Arterial Puncture

An inadvertent arterial puncture occurs most often when targeting the antecubital fossa and the brachial artery is struck instead of the median cubital vein.

Signs: Bright red blood that fills the tube rapidly and with pulsatile force; the patient may report a sharp, deep pain. The site may bleed briskly after withdrawal.

Response: Remove the needle immediately. Apply firm, continuous pressure for a minimum of five minutes—longer if the patient is on anticoagulants. Do not release pressure early to check the site. Notify your supervisor immediately. Document the event. The patient must be monitored until bleeding is fully controlled.

Petechiae

Petechiae are tiny red or purple spots caused by minor bleeding under the skin. In phlebotomy they are most often caused by leaving the tourniquet on too long (more than one to two minutes).

Response: Release the tourniquet promptly. Document the finding. Petechiae alone are not an emergency but should be reported to your supervisor.

Thrombosis and Hemoconcentration

Leaving the tourniquet on too long also causes hemoconcentration—an artificial increase in cellular and large-molecule analytes—which can distort test results. Always release the tourniquet as soon as blood flow is established or within one to two minutes.

Documentation Is Always Required

For every complication, document what happened, when it happened, how the patient responded, what you did, and who you notified. Accurate documentation is part of every within-scope response and is never optional.

Key terms9

HematomaA localized collection of blood in tissue outside the vein, appearing as swelling or bruising at or near the puncture site.
HemolysisThe rupturing of red blood cells that releases hemoglobin into the serum or plasma, rendering many laboratory tests invalid.
SyncopeA temporary loss of consciousness caused by a sudden drop in blood pressure and reduced cerebral blood flow; fainting.
Vasovagal responseA reflex triggered by pain, anxiety, or sight of blood that causes the heart rate and blood pressure to drop, leading to syncope.
Arterial punctureInadvertent puncture of an artery rather than a vein, characterized by bright red, rapidly flowing, often pulsatile blood.
PetechiaeTiny red or purple spots on the skin caused by minor bleeding beneath the surface, often from a tourniquet left on too long.
HemoconcentrationAn artificial increase in the concentration of blood cells and large molecules caused by prolonged tourniquet application, which distorts lab results.
Nerve injuryInadvertent damage to a nerve during venipuncture, typically causing immediate sharp, shooting, or electric pain that radiates from the puncture site.
Scope of practiceThe procedures, actions, and processes that a healthcare worker is permitted to perform based on their credential, training, and applicable regulations.
In class: Study a complication-response reference card covering seven common complications; complete a cause-sign-response table from memory and compare to the key in pairs. · Analyze four video or written case vignettes in which a complication occurs mid-draw, identify what went wrong, and write the immediate response steps and required documentation. · Practice the response to patient syncope: verbalize alerting a supervisor, safely lowering the patient, and applying cold compress, using a scripted role-play with instructor observation.
Materials: Complication-response reference card, cause-sign-response worksheet, case vignettes (written or video), cold compress, syncope response script, documentation form
Check: Student scores at least 80% on the complication table from memory and correctly identifies the within-scope response for all four case vignettes; syncope response role-play is pass/fail, all safety steps required.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

Specimen Collection
1. A patient says she feels dizzy and looks pale and sweaty halfway through a blood draw. Which action should the phlebotomist take FIRST?
Specimen Collection
2. Which of the following is the most common cause of hematoma formation during venipuncture?
Specimen Collection
3. A patient reports a sudden sharp, electric pain shooting into his fingers as you advance the needle. What is the correct immediate action?
Specimen Collection
4. You notice the evacuated tube is filling with bright red blood much faster than usual and the patient says the pain is sharp and deep. You suspect an arterial puncture. After removing the needle, how long should you apply firm pressure at minimum?
Specimen Collection
5. Which of the following specimen findings is most consistent with hemolysis?
Specimen Collection
6. Petechiae appear on a patient's forearm during a venipuncture procedure. What is the most likely cause?
Specimen Collection
7. After a patient faints during a blood draw, the phlebotomist removes the needle and calls for help. What is the NEXT appropriate step?
Specimen Collection
8. Which action BEST prevents hemoconcentration from affecting laboratory results?
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