NHA Certified Phlebotomy Technician (CPT)Collection RoutineHard
A phlebotomy technician is performing a venipuncture and notices that the blood flow into the vacuum tube stops abruptly after a small amount of blood has been collected. The needle is still in the vein. Which of the following is the most likely cause?
- AThe vacuum in the tube has been lost.
- BThe tourniquet was removed too soon.
- CThe needle has gone completely through the vein.
- DThe patient has a vasovagal reaction.
Show answer & explanationAnswer & explanation
Correct answer: C. The needle has gone completely through the vein.
If blood flow stops abruptly after a small amount has been collected, and the needle is still in the vein, a common cause is that the needle has gone completely through the vein. This creates a new opening in the vein wall, causing blood to leak into the surrounding tissue (hematoma formation) instead of entering the tube.
Why the other options are wrong
- A. Loss of vacuum in the tube would prevent any blood from entering, not just stop it after a small amount.
- B. Removing the tourniquet too soon would cause a gradual decrease in flow, not an abrupt stop.
- D. A vasovagal reaction typically causes fainting or lightheadedness, not an abrupt stop in blood flow from the needle.
Abrupt Blood Flow Cessation
Sudden stopping of blood flow into a collection tube during venipuncture despite the needle appearing to be in the vein.
- Common cause: needle goes through the vein.
- Blood leaks into surrounding tissue (hematoma).
- Can also be caused by bevel against vein wall or collapsed vein.
Memory trick: Flow Stops? Check the Needle's Plot!