23 Venipuncture Procedure & Complications Practice Questions & Answers

1. 1. Before drawing blood, how should a phlebotomist confirm a patient's identity?

   • A.Use at least two independent identifiers, such as name and date of birth, and compare them to the requisition and wristband✓ Answer
   • B.Ask only for the patient's room number
   • C.Confirm the patient's first name only
   • D.Rely on the name posted above the bed

   Standard practice requires two independent patient identifiers that are then matched against the requisition and wristband, because room numbers and bed labels can change and a single identifier does not reliably prevent misidentification.

   Source: CLSI GP41 — Patient Identification (two independent identifiers)Report a problem with this question

2. 2. Which method of asking a patient to state their name is considered 'active' identification?

   • A.Reading the name off the chart to the patient for agreement
   • B.Asking 'Please tell me your full name and date of birth' and letting the patient state them✓ Answer
   • C.Asking 'Are you Mr. Smith?' and waiting for a yes
   • D.Confirming identity with the patient's roommate

   Active identification requires the patient to state their identifiers unprompted, because a patient who is confused, medicated, or hard of hearing may answer 'yes' to a leading question with the wrong name.

   Source: CLSI GP41 — Active patient identificationReport a problem with this question

3. 3. Where on the arm should the tourniquet be applied relative to the intended puncture site?

   • A.At the wrist regardless of site
   • B.3 to 4 inches below the puncture site
   • C.Directly over the puncture site
   • D.3 to 4 inches above the puncture site✓ Answer

   The tourniquet is placed 3 to 4 inches above the site so it distends the veins below it without contaminating or obscuring the puncture area; placing it too close or over the site interferes with palpation and access.

   Source: CLSI GP41 — Tourniquet applicationReport a problem with this question

4. 4. What is the maximum time a tourniquet should remain applied during a routine venipuncture?

   • A.No longer than 1 minute✓ Answer
   • B.Up to 5 minutes
   • C.Until the last tube is filled, regardless of time
   • D.Up to 10 minutes

   A tourniquet left on longer than 1 minute causes hemoconcentration, where fluid leaves the vessel and concentrates cells and analytes, falsely altering results; if more time is needed it should be released and reapplied after two minutes.

   Source: CLSI GP41 — Tourniquet duration ≤1 minuteReport a problem with this question

5. 5. A patient has had a mastectomy on the left side. Which arm should generally be avoided for venipuncture?

   • A.The right arm, opposite the mastectomy
   • B.The left arm, on the same side as the mastectomy✓ Answer
   • C.Only the dominant arm
   • D.Either arm equally

   The arm on the side of a mastectomy is avoided because lymph node removal impairs lymphatic drainage, raising the risk of lymphedema and infection and altering specimen composition on that side.

   Source: CLSI GP41 — Site selection, mastectomy precautionsReport a problem with this question

6. 6. A patient has an IV line running in the left arm. What is the best action for a routine blood draw?

   • A.Draw just below the IV catheter
   • B.Draw from the opposite arm without an IV whenever possible✓ Answer
   • C.Draw directly above the running IV site
   • D.Stop the IV and draw from the same vein immediately

   Blood should be drawn from the arm without the IV, because IV fluid contaminates and dilutes the specimen, producing falsely altered analyte concentrations that do not reflect the patient's true values.

   Source: CLSI GP41 — Sites to avoid: IV armReport a problem with this question

7. 7. Which site condition is a reason to select a different vein for venipuncture?

   • A.A hematoma, or scarred or edematous tissue at the site✓ Answer
   • B.A vein that anchors firmly when palpated
   • C.A visible, resilient median cubital vein
   • D.Warm, intact skin over the antecubital area

   Hematomas, scars, and edema are avoided because blood drawn through them may be contaminated with old blood or tissue fluid and gives inaccurate results, and puncturing damaged tissue is more painful and less likely to succeed.

   Source: CLSI GP41 — Sites to avoid: hematoma, scar, edemaReport a problem with this question

8. 8. Which is the preferred vein for routine venipuncture in the antecubital area?

   • A.The median cubital vein✓ Answer
   • B.A vein on the underside of the wrist
   • C.The basilic vein first
   • D.Any wrist vein

   The median cubital vein is preferred because it is usually large, well-anchored, and located away from major nerves and the brachial artery, making it safer and less painful than the basilic vein, which lies near the artery and nerves.

   Source: CLSI GP41 — Preferred vein selectionReport a problem with this question

9. 9. Which antiseptic is standard for cleansing the site before a routine venipuncture?

   • A.Full-strength bleach
   • B.70% isopropyl alcohol✓ Answer
   • C.Plain sterile water
   • D.Hydrogen peroxide

   70% isopropyl alcohol is the standard antiseptic for routine draws because that concentration effectively reduces skin flora while evaporating cleanly, whereas water does not disinfect and harsher agents damage skin.

   Source: CLSI GP41 — Site antisepsis, 70% isopropyl alcoholReport a problem with this question

10. 10. Which antiseptic should NOT be used to clean the site when collecting a blood alcohol (ethanol) specimen?

    • A.Aqueous chlorhexidine
    • B.Isopropyl alcohol✓ Answer
    • C.Non-alcoholic soap and water
    • D.Benzalkonium chloride wipe

    Alcohol-based antiseptics must not be used for a blood alcohol draw because residual alcohol on the skin can contaminate the specimen and falsely raise the measured ethanol level; a non-alcoholic antiseptic is used instead.

    Source: CLSI GP41 — Blood alcohol specimen antisepsis (no alcohol/no iodine)Report a problem with this question

11. 11. After applying antiseptic to the puncture site, what should the phlebotomist do next?

    • A.Wipe it off immediately with a dry gauze
    • B.Insert the needle right away while it is still wet
    • C.Allow it to air-dry completely before inserting the needle✓ Answer
    • D.Fan it and re-touch the site to check dryness

    The antiseptic must air-dry completely because drying is what kills microorganisms, and puncturing while wet can sting the patient, cause hemolysis, and reintroduce contaminants; touching or wiping the site would re-contaminate it.

    Source: CLSI GP41 — Allow antiseptic to air-dryReport a problem with this question

12. 12. At what angle and orientation should the needle be inserted for a venipuncture?

    • A.15 to 30 degrees with the bevel up✓ Answer
    • B.15 to 30 degrees with the bevel down
    • C.45 to 60 degrees with the bevel up
    • D.90 degrees straight down

    A shallow 15-to-30-degree angle with the bevel up lets the needle enter the vein smoothly along its length; a steeper angle risks passing through the vein, and a bevel-down orientation impedes blood flow into the needle.

    Source: CLSI GP41 — Needle insertion 15–30°, bevel upReport a problem with this question

13. 13. A hematoma forming during a draw is most commonly caused by which of the following?

    • A.Using the correct gauge needle
    • B.The needle passing through the vein, or too little pressure after removal✓ Answer
    • C.Drawing from a large, well-anchored vein
    • D.Letting the antiseptic dry fully

    A hematoma results when blood leaks into surrounding tissue, typically because the needle punctured through the far wall of the vein or because insufficient pressure was applied to the site after needle removal.

    Source: NHA CPT Test Plan — Complications: hematoma causesReport a problem with this question

14. 14. Which practice is most likely to cause hemolysis of a specimen?

    • A.Filling the tube to its proper volume
    • B.Using an appropriately sized needle
    • C.Vigorously shaking the tube to mix it✓ Answer
    • D.Gently inverting the tube several times

    Vigorous shaking ruptures red blood cells and releases their intracellular contents into the plasma; tubes with additives must instead be mixed by gentle inversion to avoid this mechanical hemolysis.

    Source: NHA CPT Test Plan — Hemolysis causesReport a problem with this question

15. 15. A hemolyzed specimen most notably causes a falsely elevated result for which analytes?

    • A.Glucose and calcium
    • B.Sodium and chloride
    • C.Albumin and cholesterol
    • D.Potassium and LDH✓ Answer

    Potassium and LDH are far more concentrated inside red blood cells than in plasma, so when hemolysis ruptures those cells their contents spill into the plasma and falsely raise the measured levels.

    Source: NHA CPT Test Plan — Hemolysis interference (potassium, LDH)Report a problem with this question

16. 16. A patient becomes pale, sweaty, and lightheaded during a draw. What should the phlebotomist do first?

    • A.Leave the patient to get water
    • B.Apply a second tourniquet to raise blood pressure
    • C.Continue the draw quickly to finish before fainting
    • D.Stop the draw, remove the tourniquet and needle, and protect the patient from falling✓ Answer

    These are signs of impending syncope (fainting), so the draw must stop immediately and the needle be removed to prevent injury, and the patient physically supported because a fall during a faint can cause serious harm.

    Source: NHA CPT Test Plan — Syncope responseReport a problem with this question

17. 17. Repeatedly drawing excessive blood volumes, especially from small or critically ill patients, can lead to which complication?

    • A.Hemoconcentration
    • B.Lymphostasis
    • C.Petechiae
    • D.Iatrogenic anemia✓ Answer

    Removing large or frequent blood volumes faster than the body can replace red cells depletes the patient's blood supply, producing iatrogenic (treatment-caused) anemia, which is a particular risk for infants and long-term inpatients.

    Source: NHA CPT Test Plan — Iatrogenic anemiaReport a problem with this question

18. 18. Small red or purple spots (petechiae) appearing on the skin after tourniquet application most likely indicate what?

    • A.A possible coagulation or capillary/platelet problem, and a warning of prolonged bleeding✓ Answer
    • B.That the alcohol was not dry
    • C.That the needle gauge was too large
    • D.A normal, expected reaction requiring no attention

    Petechiae are tiny hemorrhages from capillaries and can signal a platelet or coagulation abnormality, alerting the phlebotomist that the patient may bleed longer than usual and the site will need extended pressure.

    Source: NHA CPT Test Plan — Petechiae significanceReport a problem with this question

19. 19. During needle insertion the patient reports a sharp, shooting, electric-like pain radiating down the arm. What should the phlebotomist do?

    • A.Remove the needle immediately, as this suggests nerve involvement✓ Answer
    • B.Ignore it and continue since pain is expected
    • C.Push the needle deeper to reach the vein
    • D.Rotate the needle in place until the pain stops

    Sharp, radiating, electric pain indicates the needle has contacted or irritated a nerve, so it must be withdrawn at once to prevent lasting nerve injury; continuing or repositioning would worsen the damage.

    Source: NHA CPT Test Plan — Nerve injury recognitionReport a problem with this question

20. 20. The blood entering the tube is bright red and appears to pulse or spurt. What has most likely happened and what is the correct response?

    • A.The tube additive caused the color; keep drawing
    • B.It is normal venous blood; continue as usual
    • C.An artery was punctured; remove the needle and apply firm pressure for an extended time✓ Answer
    • D.Hemolysis occurred; shake the tube to mix

    Bright red, pulsating blood signals inadvertent arterial puncture; the needle must be removed and firm pressure held for an extended period (often 5 minutes or more) because arteries bleed under high pressure and can form large hematomas.

    Source: NHA CPT Test Plan — Inadvertent arterial punctureReport a problem with this question

21. 21. When and where should blood collection tubes be labeled?

    • A.At the bedside, in the patient's presence, immediately after collection✓ Answer
    • B.Before the draw, once the requisition is printed
    • C.At the nurses' station after leaving the room
    • D.In the laboratory when the specimens arrive

    Tubes are labeled at the bedside in the patient's presence right after the draw so the specimen can be positively matched to the verified patient; labeling elsewhere or beforehand creates a risk of mislabeling and misidentification.

    Source: CLSI GP41 — Specimen labeling at point of collectionReport a problem with this question

22. 22. The needle is in but no blood is flowing. Which is an appropriate corrective action?

    • A.Push the needle in to the hub immediately
    • B.Probe aggressively side to side until a vein is hit
    • C.Make unlimited attempts in the same site
    • D.Slightly reposition the needle or try a new tube, and limit to two attempts before asking another phlebotomist✓ Answer

    Small adjustments such as gently advancing, withdrawing slightly, or changing the tube can restore flow, but attempts should be limited (generally to two) and then handed off, because repeated blind probing causes pain, nerve injury, and hematoma.

    Source: NHA CPT Test Plan — Failure to obtain blood; two-attempt limitReport a problem with this question

23. 23. A test requires a fasting specimen. What does 'fasting' typically require of the patient beforehand?

    • A.A large meal one hour before the draw
    • B.No water of any kind for 24 hours
    • C.Nothing special; fasting has no effect on results
    • D.No food or caloric drinks, only water, for about 8 to 12 hours before the draw✓ Answer

    Fasting typically means no food or caloric beverages for roughly 8 to 12 hours, with water allowed, because recent food intake raises glucose and lipids and would skew tests such as glucose and lipid panels.

    Source: NHA CPT Test Plan — Fasting requirements (8–12 hours)Report a problem with this question

Concept-focused practice questions based on CLSI GP41 (venous blood collection), the CLSI order of draw, and the OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030). Not affiliated with the NHA, ASCP, or CLSI, and not medical advice. Facility protocols and current CLSI standards take precedence — always follow your employer's procedures. About the CPT exam →