CERTIFIED PHLEBOTOMY TECHNICIAN (CPT) COMPREHENSIVE EXAM PREPARATION PRACTICE QUESTIONS WITH ANSWERS AND RATIONALES

CERTIFIED PHLEBOTOMY TECHNICIAN (CPT) COMPREHENSIVE EXAM PREPARATION PRACTICE QUESTIONS WITH ANSWERS AND RATIONALES 1. A patient with a history of mastectomy on the left side requires blood collection. Which site is most appropriate? A) Left basilic vein B) Left cephalic vein C) Right median cubital vein D) Left dorsal hand vein Correct Answer: C Rationale: After mastectomy, lymph edema risk is high on the ipsilateral side. Venipuncture should be performed on the unaffected arm unless medically cleared otherwise. The right arm is preferred. ________________________________________ 2. Which additive is found in a light blue top tube? A) EDTA B) Sodium citrate C) Heparin D) Potassium oxalate Correct Answer: B Rationale: Light blue top tubes contain sodium citrate, which binds calcium and is used for coagulation studies (e.g., PT, PTT). ________________________________________ 3. During a capillary puncture on a heel of an infant, which site is correct? A) Center of the heel B) Posterior curvature of the heel C) Medial or lateral plantar surface D) Arch of the foot Correct Answer: C Rationale: In infants, the medial and lateral plantar surfaces are safe. The center risks bone injury (osteochondritis); the posterior curvature is also unsafe. ________________________________________ 4. A tourniquet is left on for 3 minutes. What effect may this have? A) Hemoconcentration B) Hemolysis C) No effect D) Decreased potassium levels Correct Answer: A Rationale: Prolonged tourniquet application causes fluid shift from intravascular to interstitial, leading to hemoconcentration and falsely elevated analytes (e.g., potassium, protein). ________________________________________ 5. Which tube should be collected first when using a butterfly with a syringe and blood culture bottles? A) Light blue top B) Sterile aerobic bottle C) Lavender top D) Green top Correct Answer: B Rationale: Blood cultures are collected first to minimize contamination risk. Anaerobic then aerobic is standard, but aerobic first is acceptable if using a butterfly due to air in tubing. ________________________________________ 6. A patient reports feeling faint during venipuncture. Your first action is: A) Remove the needle immediately B) Fan the patient’s face C) Lower the patient’s head or raise legs D) Complete the draw quickly Correct Answer: C Rationale: Syncope risk requires increasing cerebral blood flow. Lowering head or raising legs (Trendelenburg) is immediate first aid; needle removal follows only if severe. ________________________________________ 7. What is the order of draw for a lavender, green, and light blue top using a closed system? A) Light blue, green, lavender B) Green, light blue, lavender C) Lavender, green, light blue D) Light blue, lavender, green Correct Answer: A Rationale: Order of draw per CLSI: Light blue (clotting factors), then green (heparin), then lavender (EDTA) to prevent cross-contamination of additives. ________________________________________ 8. Which needle gauge is typically used for routine adult venipuncture? A) 18G B) 21G C) 25G D) 27G Correct Answer: B Rationale: 21G is standard for routine adult venipuncture—large enough to prevent hemolysis, small enough for patient comfort. 23G is also common but 21G is most referenced. ________________________________________ 9. Why should you never use a hemolyzed specimen for potassium testing? A) Hemolysis decreases potassium B) Hemolysis releases intracellular potassium C) Hemolysis activates clotting factors D) Hemolysis damages red cell membranes, lowering sodium Correct Answer: B Rationale: Hemolysis releases potassium from RBCs into serum/plasma, causing falsely elevated potassium, which can lead to critical misdiagnosis (e.g., hyperkalemia). ________________________________________ 10. Which antiseptic is preferred for blood culture collection? A) 70% isopropyl alcohol alone B) Povidone-iodine C) Chlorhexidine gluconate D) Hydrogen peroxide Correct Answer: C Rationale: Chlorhexidine gluconate is superior for blood cultures due to rapid, persistent antimicrobial action. Povidone-iodine is acceptable but requires longer drying. ________________________________________ 11. A patient has an IV in the right forearm and left antecubital. Where should you draw? A) Below the IV in the right arm B) Left hand C) Right hand D) Left arm above the IV site Correct Answer: B Rationale: Draw from a site distal to the IV, preferably the opposite arm. If both arms have IVs, use distal site (hand) on the arm without an IV in antecubital.