Unit 3: Phlebotomy and Laboratory Procedures

• Topic 01

  Venepuncture — Anatomy of the Antecubital Fossa

  29 questions
• Topic 02

  Venepuncture Technique — Syringe, Evacuated Tube, and Butterfly

  35 questions
• Topic 03

  Capillary (Fingerstick and Heelstick) Collection

  39 questions
• Topic 04

  Order of Draw — Tube Types, Additives, and Sequence

  33 questions
• Topic 05

  Specimen Labelling and Chain of Custody

  33 questions
• Topic 06

  Specimen Handling — Centrifugation, Transport, and Storage

  52 questions
• Topic 07

  Point-of-Care Testing — Glucose, Cholesterol, and CLIA-Waived Tests

  45 questions
• Topic 08

  Haematology Basics — CBC Components and Reference Ranges

  45 questions
• Topic 09

  Complications and Adverse Events in Blood Collection

  48 questions

A few questions from this unit, with the answer and a full explanation. The complete bank is available when you start practising.

1. After a patient faints during a blood draw, the phlebotomist is considering the correct recovery position. Should the patient be immediately laid completely flat on the floor?

   • A
     No, the patient should remain seated upright because a reclined position risks aspiration
   • B
     No, syncope patients should always be placed in the right lateral (recovery) position only
   • C
     Yes, lay the patient flat on the floor and immediately begin chest compressions
   • D
     Not necessarily; the preferred position is reclined with head lowered (or Trendelenburg), ensuring the patient does not fall; completely flat is acceptable but safety and prevention of falls takes priority over exact position
     Correct answer
   Explanation

   Textbooks and CLSI guidance indicate the preferred response to syncope is to lower the patient's head below their heart level — typically achieved by reclining a phlebotomy chair — to restore cerebral perfusion. A completely flat floor position is also appropriate when safely achievable, but the first priority is preventing injury from falling, not achieving a specific degree of flatness. The Trendelenburg position (feet slightly elevated) is ideal but not always feasible. Keeping the patient seated upright risks continued cerebral hypoperfusion and worsening syncope. Key takeaway: lower the head and prevent falling — exact positioning is secondary to ensuring the patient does not sustain injury during loss of consciousness.

2. A phlebotomist applies a tourniquet and then spends 3 minutes palpating, selecting a vein, and preparing the site before collecting blood. The tourniquet remained on throughout. Which analytes are most likely falsely elevated in this specimen?

   • A
     Glucose and creatinine are the primary analytes falsely elevated by prolonged tourniquet use
   • B
     Potassium, proteins (albumin, total protein), red blood cell count, hemoglobin, and hematocrit are falsely elevated due to hemoconcentration from prolonged tourniquet application
     Correct answer
   • C
     PT/INR and aPTT are falsely prolonged because the tourniquet activates clotting factors through venous stasis
   • D
     Only troponin is falsely elevated by prolonged tourniquet; other analytes are unaffected by venous occlusion up to 5 minutes
   Explanation

   Prolonged tourniquet application (≥1 minute) causes venous stasis and increased hydrostatic pressure, driving water and small molecules out of the capillaries into the interstitial space. This concentrates large molecules (proteins, cells) in the venous blood — a phenomenon called hemoconcentration. Analytes falsely elevated include: potassium (from cellular leakage under pressure), albumin, total protein, RBC count, hemoglobin, hematocrit, LDH, and lipids. The CLSI GP41-A6 maximum of 1 minute prevents this artifact. Key takeaway: 3 minutes of tourniquet = hemoconcentration — falsely elevates K+, proteins, CBC cell counts; the tourniquet must be released within 1 minute or as soon as blood flows.

3. What is the minimum number of patient identifiers required on a specimen label?

   • A
     No specific number is required — any unique information is acceptable
   • B
     One identifier for inpatients and two for outpatients
   • C
     One patient identifier (name only is sufficient)
   • D
     Two patient identifiers
     Correct answer
   Explanation

   The Joint Commission National Patient Safety Goal (NPSG) 01.01.01 requires that at least two patient identifiers be used whenever providing care, treatment, or services — including specimen collection and labelling. CLSI GP33-A reinforces this requirement. The two-identifier rule exists to prevent specimen mix-ups and wrong-blood-in-tube (WBIT) errors, which can be fatal in transfusion medicine. Key takeaway: Always use a minimum of two patient identifiers on every specimen label — this is both a Joint Commission NPSG and a CLSI requirement.