This question-specific review guide is tied to the answer reasoning for a PracticeTestVault item. Use it after you answer the question so the review stays focused on what the prompt actually tested.
What this question is testing
Objective: Specimen integrity
Prompt focus: Whole blood collected for molecular testing of nucleic acids is most appropriately collected in a tube containing which anticoagulant?
Why the correct answer works
EDTA, because heparin can inhibit downstream PCR amplification
Correct. EDTA is preferred for molecular testing because heparin is a PCR inhibitor that can interfere with amplification.
Why the tempting wrong answer fails
The tempting wrong answer usually loses because it skips the key condition, priority, or evidence in the prompt.
Plain-language takeaway
EDTA is the preferred anticoagulant for molecular testing because it chelates metal ions without interfering with PCR. Heparin is a known PCR inhibitor and can carry over into extracted nucleic acid, so heparinized tubes are generally avoided.
Simple analogy
Think of specimen integrity like following a short checklist: identify the clue, confirm the rule, and then make the move that fits this exact scenario.
How to review it before a retake
- Underline the command word and name what the question is asking before rereading the choices.
- Compare the correct answer against the closest distractor and write the exact detail that separates them.
- Retest this objective with a fresh question without looking at the rationale first.