NHI Phlebotomy and Lab Procedures 3 — Questions and Answers
Question 1: What is the recommended angle of needle insertion for standard venipuncture?
- 5–10 degrees
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 70–90 degrees
Correct answer: 15–30 degrees
A 15–30 degree angle allows the needle to enter the vein smoothly without passing through the posterior wall.
Question 2: Which evacuated tube color is used for serum chemistry tests and contains a clot activator?
- Lavender
- Light blue
- Green
- Gold/Red-gray SST (Correct answer)
Correct answer: Gold/Red-gray SST
Gold or red-gray serum separator tubes (SSTs) contain silica particles that activate clotting and a gel that separates serum from the clot after centrifugation.
Question 3: A specimen labeled 'QNS' has been rejected by the laboratory. What does QNS mean?
- Quality Not Sufficient
- Quantity Not Sufficient (Correct answer)
- Quench No Sample
- Queue Not Started
Correct answer: Quantity Not Sufficient
QNS means 'Quantity Not Sufficient,' indicating the specimen volume is inadequate to perform the ordered tests.
Question 4: When performing capillary puncture on an infant's heel, which area should be AVOIDED?
- Lateral plantar surface
- Medial plantar surface
- Central posterior curvature of the heel (Correct answer)
- Lateral heel surface
Correct answer: Central posterior curvature of the heel
The central posterior curvature of the heel is too close to the calcaneus bone, risking osteomyelitis (bone infection) in infants.
Question 5: Which type of specimen collection is used for blood cultures to detect systemic infection?
- One venipuncture into a single aerobic bottle
- Two separate venipunctures, each yielding aerobic and anaerobic bottles (Correct answer)
- A fingerstick into a microtube
- A central line draw into lavender tubes
Correct answer: Two separate venipunctures, each yielding aerobic and anaerobic bottles
Blood cultures require two separate venipuncture sites to reduce false positives from contamination, each yielding aerobic and anaerobic culture bottles.
Question 6: What is the correct action if a patient faints (syncope) during blood collection?
- Continue collection quickly to finish before the patient wakes
- Remove the needle, lower the patient's head, and call for assistance (Correct answer)
- Apply smelling salts and restart immediately
- Elevate the patient's feet while keeping the needle in place
Correct answer: Remove the needle, lower the patient's head, and call for assistance
The needle must be removed immediately for safety, the patient's head lowered to restore cerebral blood flow, and assistance summoned.
Question 7: Which laboratory test requires a light blue (sodium citrate) tube and a 9:1 blood-to-additive ratio?
- Complete blood count (CBC)
- Prothrombin time (PT/INR) (Correct answer)
- Comprehensive metabolic panel
- Thyroid-stimulating hormone (TSH)
Correct answer: Prothrombin time (PT/INR)
Coagulation tests like PT/INR use light blue tubes with sodium citrate, and the 9:1 ratio is critical for accurate coagulation results.
NHI Phlebotomy and Lab Procedures 3
What is the recommended angle of needle insertion for standard venipuncture?