11.4 Phlebotomy and Specimen Reference Checklist

Phlebotomy Reference

Phlebotomy stems usually hide one clue that should stop or change the draw. Before collection, verify two patient identifiers, match the requisition, confirm test/tube type and timing (e.g., fasting, timed glucose), assess the site, and explain the procedure.

Stop-or-Proceed Clues

Tourniquet rule: apply 3-4 inches above the site and release within 1 minute to avoid hemoconcentration. The median cubital vein in the antecubital fossa is the first-choice site.

Order of Draw and Tube Additives (CLSI / CDC)

This CDC-recognized sequence prevents additive carryover (e.g., EDTA contaminating a chemistry tube falsely lowers calcium and raises potassium). Never pour blood from one tube into another to fix a fill problem.

Specimen Integrity

• Light blue must be filled to the line: an under-fill skews the blood-to-citrate ratio and invalidates coagulation results.
• Lavender that clots invalidates the CBC; mix EDTA tubes by gentle inversion ~8-10 times, never shake.
• Hemolysis (falsely high potassium) comes from a too-small needle, vigorous shaking, forceful transfer, or drawing through a hematoma.
• Label at the point of care in the patient's presence; unlabeled, leaking, or delayed specimens are rejected and recollected.

Last-Minute Self-Test

Capillary (Dermal) Collection

Capillary sticks are tested alongside venipuncture, especially for infants and for point-of-care glucose. For an adult fingerstick, use the side of the third or fourth fingertip and discard the first drop, which is diluted with tissue fluid and can skew results. For infants under one year, use the medial or lateral plantar surface of the heel, never the center of the heel or the curved back, to avoid striking the calcaneus bone and causing injury. Warming the site increases blood flow and improves sample quality.

The capillary order of draw differs from venipuncture: collect EDTA (lavender) tubes first, then other additive tubes, then serum, because hematology testing is most sensitive to clotting in a slow-flowing capillary sample.

Patient-Prep Variables

Many tests have prep requirements that, if missed, invalidate the result. A fasting glucose or lipid panel generally requires 8-12 hours without food; a timed test like a two-hour glucose tolerance test depends on exact collection times. The CCMA confirms the patient followed the prep before drawing and documents any deviation. Diet, recent exercise, posture, and time of day can all influence results.

Specimen Rejection and Recollection

When integrity fails, the correct path is recollection and notification, never quietly fixing the paperwork. The leading rejection causes are an unlabeled or mislabeled tube, a clotted anticoagulant specimen, an under-filled coagulation tube, hemolysis, an insufficient quantity (QNS), the wrong tube for the test, and excessive transport delay or improper temperature. Transferring blood between tubes to correct a fill error is prohibited because it cross-contaminates additives and falsifies results. If a specimen leaks in transit, follow the exposure and spill policy, then recollect.

The exam reward goes to the candidate who protects identity and integrity over the one who tries to salvage a compromised sample.

Complications and Patient Safety at the Chair

Venipuncture has recognized complications, and the exam tests calm, correct responses. Syncope (fainting) is the most common: never draw a standing patient, and at the first sign of pallor, sweating, or lightheadedness, stop, remove the needle, lower the head, and protect the patient from falling. A hematoma forms when blood leaks into tissue; release the tourniquet and needle and apply firm pressure. Nerve injury is signaled by sharp, electric, or radiating pain or tingling - withdraw the needle immediately and do not redirect blindly.

Petechiae can warn of a bleeding tendency, and prolonged oozing in a patient on anticoagulants calls for extended pressure. Probing, excessive redirecting, and repeated sticks increase injury and hemolysis risk, so two failed attempts is the customary cue to ask a colleague or notify the provider rather than persist. Document the attempts, the site used, and the patient's tolerance. The unifying principle, again, is that patient safety and specimen integrity outrank getting the tube filled on the first try.