NCCT - National Certified Phlebotomy Technician Collection Complications and Corrections Questions and Answers 1 — Questions and Answers
Question 1: A phlebotomist applies a tourniquet and is momentarily distracted, leaving it on the patient's arm for nearly three minutes before performing the venipuncture. This delay is most likely to cause what type of preanalytical error?
- Specimen contamination
- Hemoconcentration (Correct answer)
- Vein collapse
- Hemolysis
Correct answer: Hemoconcentration
Leaving a tourniquet on for longer than one minute causes venous stasis, where plasma is forced out of the vein into the surrounding tissue. This results in an increased concentration of non-filterable analytes like proteins, enzymes, and cells in the blood specimen, a condition known as hemoconcentration.
Question 2: Which of the following procedural errors is a common cause of hemolysis, the rupture of red blood cells, in a blood specimen?
- Using a 23-gauge needle on a small, fragile vein
- Anchoring the vein firmly below the puncture site
- Vigorously shaking the collection tube after the draw (Correct answer)
- Allowing the tube to fill completely until the vacuum is exhausted
Correct answer: Vigorously shaking the collection tube after the draw
Vigorously shaking a tube creates mechanical trauma that can rupture red blood cells, leading to hemolysis. Tubes with additives should be gently inverted the specified number of times to ensure proper mixing without damaging the cells.
Question 3: During a venipuncture on a patient with small veins, the phlebotomist observes that the blood flow into the evacuated tube stops after only a small amount has been collected and the vein appears to flatten. What is the most likely cause of this complication?
- The bevel of the needle is resting against the vein wall
- The vacuum of the evacuated tube is too strong for the vein (Correct answer)
- The tourniquet was not applied tightly enough
- The needle has passed completely through the vein
Correct answer: The vacuum of the evacuated tube is too strong for the vein
A collapsed vein occurs when the pressure exerted by the evacuated tube's vacuum is greater than the pressure of the blood flowing through the vein, causing the vein walls to draw together and stop the flow. This is more common in patients with small or fragile veins.
Question 4: A phlebotomist performing a venipuncture in the antecubital area notices the blood in the collection tube is bright red and filling rapidly with a pulsating flow. What is the phlebotomist's most appropriate immediate action?
- Complete the draw and label the specimen as a 'possible arterial sample'
- Pull the needle back slightly to see if it re-enters the vein
- Continue filling the tube, as this indicates good blood flow
- End the draw, remove the needle, and apply firm pressure for at least 5-10 minutes (Correct answer)
Correct answer: End the draw, remove the needle, and apply firm pressure for at least 5-10 minutes
Bright red, pulsating blood is a clear sign of an inadvertent arterial puncture. Because arterial pressure is much higher than venous pressure, the immediate priority is to stop the procedure and apply significant, prolonged pressure to the site to prevent a large hematoma and control bleeding.
Question 5: After applying a tourniquet to a patient's arm, the phlebotomist observes small, non-raised red spots appearing on the skin below the tourniquet. What does this clinical sign indicate?
- The patient has sclerosed veins unsuitable for puncture
- The tourniquet is not tight enough to engorge the veins
- The formation of petechiae, suggesting capillary fragility (Correct answer)
- An allergic reaction to the latex in the tourniquet
Correct answer: The formation of petechiae, suggesting capillary fragility
The appearance of small red spots, or petechiae, after tourniquet application indicates minor hemorrhage from fragile capillaries. This can be a sign of a low platelet count or other coagulation issues, and the phlebotomist should be prepared to apply extra pressure to the site after the draw to ensure bleeding stops.
Question 6: A phlebotomist is assessing a patient's arms for a suitable venipuncture site and notes that the right arm appears swollen and the skin is taut and shiny. Why should this edematous site be avoided for blood collection?
- Puncturing an edematous site is significantly more painful for the patient.
- The excess tissue fluid can contaminate the blood specimen and alter test results. (Correct answer)
- The veins in an edematous arm are typically thrombosed and will not yield blood.
- The tourniquet will not be effective and may cause further swelling.
Correct answer: The excess tissue fluid can contaminate the blood specimen and alter test results.
Edema is the accumulation of excess interstitial fluid in the tissues. Collecting a blood sample from an edematous area can lead to contamination and dilution of the specimen with this fluid, causing inaccurate test results. It can also be difficult to palpate a vein in such an area.
NCCT - National Certified Phlebotomy Technician Collection Complications and Corrections Questions and Answers 1
A phlebotomist applies a tourniquet and is momentarily distracted, leaving it on the patient's arm for nearly three minutes before performing the venipuncture.
This delay is most likely to cause what type of preanalytical error?