ASPT Specimen Handling and Processing 3 — Questions and Answers
Question 1: A urine specimen for culture must be transported to the lab but will take 45 minutes. What is the correct action?
- Transport at room temperature without concern
- Refrigerate the specimen during transport (Correct answer)
- Add a preservative and store at room temperature
- Freeze the specimen immediately
Correct answer: Refrigerate the specimen during transport
Urine culture specimens must be refrigerated if transport time exceeds 30 minutes to prevent bacterial overgrowth that would alter results.
Question 2: Which of the following analytes requires a light-protected specimen container during transport?
- Glucose
- Potassium
- Bilirubin (Correct answer)
- Sodium
Correct answer: Bilirubin
Bilirubin is photosensitive and degrades when exposed to light, requiring amber or foil-wrapped tubes during collection and transport.
Question 3: What is the correct centrifugation speed range for most routine blood specimens?
- 500–800 × g
- 1,000–1,200 × g
- 1,500–2,500 × g (Correct answer)
- 3,000–4,000 × g
Correct answer: 1,500–2,500 × g
Most routine blood specimens are centrifuged at 1,500–2,500 × g for 10–15 minutes to adequately separate cellular components from plasma or serum.
Question 4: A plasma specimen is needed for STAT glucose testing. Which tube should be used?
- Red top (no additive)
- Light blue top (sodium citrate)
- Green top (heparin) (Correct answer)
- Yellow top (SPS)
Correct answer: Green top (heparin)
Lithium heparin (green top) tubes provide plasma immediately after centrifugation without a clotting wait time, making them ideal for STAT testing.
Question 5: Which condition would cause a specimen to be rejected by the laboratory?
- Specimen collected in the correct tube
- Specimen labeled at the bedside after collection
- Specimen with clots in an EDTA tube (Correct answer)
- Specimen that arrived within 30 minutes of collection
Correct answer: Specimen with clots in an EDTA tube
Clots in an EDTA tube indicate improper mixing and will interfere with cell counts and other hematology tests, requiring specimen rejection.
Question 6: What is the purpose of a blood culture bottle's aerobic and anaerobic pairing?
- To test for fungal infections only
- To detect both oxygen-requiring and oxygen-sensitive organisms (Correct answer)
- To allow longer specimen storage
- To increase the volume of blood collected
Correct answer: To detect both oxygen-requiring and oxygen-sensitive organisms
Aerobic bottles support oxygen-requiring bacteria while anaerobic bottles support organisms that are inhibited or killed by oxygen, providing complete pathogen detection.
Question 7: How should a specimen be handled if it cannot be tested within the recommended stability window?
- Run the test anyway and note the delay
- Freeze the specimen at –20°C or lower
- Add a chemical preservative to extend stability
- Discard and recollect if possible (Correct answer)
Correct answer: Discard and recollect if possible
When a specimen exceeds stability limits, the preferred action is recollection because testing an unstable specimen produces unreliable results that could harm patient care.
ASPT Specimen Handling and Processing 3
A urine specimen for culture must be transported to the lab but will take 45 minutes.
What is the correct action?