Standard Operating Procedure: Clinical Phlebotomy

Introduction

This Standard Operating Procedure (SOP) outlines the mandatory protocols for the collection of venous blood specimens. The objective of this document is to ensure patient safety, maintain specimen integrity, and minimize the risk of pre-analytical errors. Adherence to these guidelines is essential for the prevention of infection, reduction of hemolysis, and maintenance of accurate laboratory diagnostic reporting. All phlebotomists must follow these steps for every patient encounter without exception.

Pre-Collection Procedures

• Verify Patient Identity: Utilize two patient identifiers (Full Name and Date of Birth). Compare these against the laboratory requisition form and the patient's wristband.
• Review Requisition: Confirm that all test orders are clear, identify the correct tube requirements, and check for any special handling instructions (e.g., chilled, protected from light).
• Sanitize Equipment: Clean the phlebotomy tray and ensure all supplies (needles, tubes, alcohol pads, gauze, tape) are within expiration dates.
• Hand Hygiene: Perform thorough hand washing (or use hospital-grade alcohol-based sanitizer) immediately before donning non-sterile gloves.

Collection Process

• Patient Positioning: Ensure the patient is seated or reclined safely to prevent injury in the event of syncope.
• Site Selection: Inspect both arms for suitable veins. Palpate to determine size, depth, and bounce. Avoid areas with hematomas, scars, rashes, or IV lines.
• Apply Tourniquet: Place 3–4 inches above the intended puncture site. Do not leave the tourniquet on for more than 60 seconds to prevent hemoconcentration.
• Site Preparation: Clean the site with a 70% isopropyl alcohol pad using a concentric circular motion moving outward. Allow the site to air dry completely (do not blow or fan).
• Venipuncture:
  • Anchor the vein firmly by pulling the skin taut below the site.
  • Insert the needle at a 15–30 degree angle, bevel up.
  • Once blood flow is established, push the collection tube onto the needle hub.
• Tube Management: Follow the standard Order of Draw (Blood culture, Coagulation/Blue, Serum/Red/Gold, Heparin/Green, EDTA/Lavender, Glycolytic Inhibitor/Gray).
• Mixing: Gently invert additive tubes 5–10 times immediately after removal from the holder. Do not shake.

Post-Collection and Specimen Handling

• Safety Withdrawal: Apply gauze gently over the site and withdraw the needle in a single, smooth motion. Immediately activate the needle safety mechanism.
• Hemostasis: Apply firm, direct pressure to the puncture site. Instruct the patient to keep their arm straight and hold pressure for at least 2 minutes.
• Disposal: Dispose of the used needle immediately into the approved sharps container.
• Labeling: Label all tubes at the bedside in the presence of the patient. Include your initials, date, and time of collection.
• Final Inspection: Inspect the puncture site to ensure bleeding has stopped before applying a bandage.

Pro Tips & Pitfalls

• Pro Tip: If a vein is difficult to find, apply a warm compress for 3–5 minutes to increase vasodilation.
• Pro Tip: Always prioritize comfort; if the patient is nervous, engage them in conversation to distract them and lower their blood pressure.
• Pitfall (Hemolysis): The most common cause is pulling the plunger too fast on a syringe or using a needle gauge that is too small (e.g., 25G) for the draw.
• Pitfall (Hematoma): Failure to release the tourniquet before removing the needle or applying insufficient pressure after withdrawal.
• Pitfall (Short Draws): Under-filling additive tubes (especially blue-top citrate tubes) will lead to an incorrect blood-to-additive ratio and erroneous coagulation results.

Frequently Asked Questions

Q: What should I do if the patient refuses the procedure? A: You must respect the patient's right to refuse. Document the refusal clearly in the medical record, notify the ordering physician, and do not attempt to coerce the patient.

Q: If I cannot obtain blood after two attempts, what is the protocol? A: Stop the procedure. Do not attempt a third stick yourself. Seek assistance from a senior colleague or notify the nursing staff to determine if an alternative collection method is required.

Q: Can I draw blood from an arm with an active IV line? A: Avoid drawing from the same arm as an IV line. If absolutely necessary, collect blood distal (below) to the IV site, and ensure the IV is turned off for at least 2 minutes prior to draw to prevent sample contamination with IV fluids.