CPC Specimen Collection Procedures & Chain of Custody 2 — Questions and Answers
Question 1: Which additive in a lavender-top (EDTA) tube is primarily used for hematology testing?
- Sodium citrate
- Ethylenediaminetetraacetic acid (EDTA) (Correct answer)
- Lithium heparin
- Sodium fluoride
Correct answer: Ethylenediaminetetraacetic acid (EDTA)
EDTA chelates calcium ions to prevent blood from clotting, making it ideal for hematology studies such as CBC.
Question 2: When collecting a urine specimen for a chain-of-custody drug screen, what is the minimum required volume typically specified?
- 15 mL
- 30 mL (Correct answer)
- 45 mL
- 60 mL
Correct answer: 30 mL
Federal workplace drug testing guidelines require a minimum of 30 mL for a urine specimen to allow for split-sample testing.
Question 3: A collector notices the donor's urine temperature reads 94°F (34.4°C) immediately after collection. What is the correct action?
- Accept the specimen as valid (Correct answer)
- Discard and have the donor provide another specimen
- Document the temperature and proceed normally
- Report to the MRO immediately and discard
Correct answer: Accept the specimen as valid
Acceptable urine temperature range is 90–100°F (32–38°C), so 94°F falls within this range and the specimen should be accepted.
Question 4: What is the purpose of the 'split specimen' procedure in federal workplace drug testing?
- To test for a wider panel of drugs simultaneously
- To allow the donor to request a retest of the same collection at a different lab (Correct answer)
- To divide the sample for immediate and future analysis
- To reduce laboratory processing time
Correct answer: To allow the donor to request a retest of the same collection at a different lab
The split specimen (Bottle B) is sealed and stored; if the donor challenges a positive result, Bottle B is sent to another certified lab for confirmation.
Question 5: Which of the following actions is REQUIRED before sealing a forensic urine specimen under chain of custody?
- Centrifuging the specimen
- Having the donor initial the tamper-evident seal over the bottle cap (Correct answer)
- Adding a preservative to the specimen
- Measuring the specific gravity
Correct answer: Having the donor initial the tamper-evident seal over the bottle cap
The donor must initial the tamper-evident seal in the collector's presence to establish the chain of custody and prevent tampering allegations.
Question 6: When performing a venipuncture, what is the correct order of draw when collecting both a gray-top and a green-top tube?
- Gray-top first, then green-top
- Green-top first, then gray-top (Correct answer)
- Either order is acceptable
- Order depends on the patient's diagnosis
Correct answer: Green-top first, then gray-top
Per CLSI guidelines, lithium heparin (green) is drawn before sodium fluoride/potassium oxalate (gray) to prevent additive cross-contamination affecting glucose results.
Question 7: A chain-of-custody form must accompany a specimen throughout the entire testing process primarily to:
- Ensure the specimen is processed within 24 hours
- Document every person who handled the specimen and maintain legal defensibility (Correct answer)
- Identify the type of analysis to be performed
- Record the patient's medical history
Correct answer: Document every person who handled the specimen and maintain legal defensibility
The chain-of-custody form creates an unbroken documentary record of all individuals who handled the specimen, which is essential for legal and evidentiary purposes.
CPC Specimen Collection Procedures & Chain of Custody 2
Which additive in a lavender-top (EDTA) tube is primarily used for hematology testing?