Certified Phlebotomy Technician Exam Special Specimen Collections 3 — Questions and Answers
Question 1: Which specimen collection technique is used for a PKU (phenylketonuria) newborn screen?
- Venipuncture into an EDTA tube
- Heel stick spotted onto filter paper cards (Correct answer)
- Midstream clean-catch urine
- Nasopharyngeal swab
Correct answer: Heel stick spotted onto filter paper cards
Newborn screening for PKU uses a heel stick with blood drops spotted onto specialized filter paper (Guthrie cards) and allowed to dry.
Question 2: When performing a capillary puncture on an infant, which part of the heel is the correct puncture site?
- The central plantar surface of the heel
- The medial or lateral plantar surface of the heel (Correct answer)
- The posterior curvature of the heel
- The arch of the foot
Correct answer: The medial or lateral plantar surface of the heel
The medial or lateral plantar surface of the heel is the safe zone for infant heel sticks, avoiding the posterior curve where the calcaneus is closest to the skin.
Question 3: A patient requires a fasting lipid panel. Which of the following foods/drinks is acceptable before the draw?
- Black coffee
- Orange juice
- A small piece of toast
- Water (Correct answer)
Correct answer: Water
Only plain water is permitted during a fasting period; coffee, juice, and food can alter lipid and glucose values.
Question 4: What additive is found in the gray-top tube used for glucose testing?
- EDTA and sodium fluoride
- Sodium fluoride and potassium oxalate (Correct answer)
- Lithium heparin
- Sodium citrate
Correct answer: Sodium fluoride and potassium oxalate
Gray-top tubes contain sodium fluoride (glycolytic inhibitor) and potassium oxalate (anticoagulant) to preserve glucose levels in the specimen.
Question 5: When is a cold agglutinin specimen collection required?
- When testing for autoimmune hemolytic anemia caused by cold-reactive antibodies (Correct answer)
- Whenever a patient has a fever above 103°F
- For all blood bank crossmatch specimens
- For cryoglobulin testing only
Correct answer: When testing for autoimmune hemolytic anemia caused by cold-reactive antibodies
Cold agglutinins are antibodies that bind red blood cells at low temperatures; the specimen must be kept warm (37°C) from collection to separation to prevent in vitro agglutination.
Question 6: Which of the following best describes a midstream clean-catch urine collection?
- The first portion of the urine stream is collected
- The urethral area is cleaned, the first portion discarded, and the middle portion collected (Correct answer)
- The entire void is collected into a sterile container
- A catheter is inserted to obtain the specimen
Correct answer: The urethral area is cleaned, the first portion discarded, and the middle portion collected
A clean-catch midstream collection involves cleansing the urethral area, discarding the initial stream (which flushes contaminants), and collecting the midstream portion.
Question 7: For a sweat chloride test used to diagnose cystic fibrosis, how is sweat stimulated?
- The patient exercises vigorously for 30 minutes
- Pilocarpine iontophoresis is applied to the skin (Correct answer)
- A heating pad is placed on the forearm
- Intravenous saline causes perspiration
Correct answer: Pilocarpine iontophoresis is applied to the skin
Pilocarpine iontophoresis uses a mild electric current to drive the sweat-stimulating drug pilocarpine into the skin, producing a localized sweat sample.
Certified Phlebotomy Technician Exam Special Specimen Collections 3
Which specimen collection technique is used for a PKU (phenylketonuria) newborn screen?