PCR Specimen Collection & Handling 5

Question 1

Before collecting a saliva specimen for PCR, what should the patient avoid for at least 30 minutes?

Accepted Answer

Eating, drinking, smoking, or brushing teeth

Answer

Food, drink, and oral products can dilute the sample or introduce PCR inhibitors.

Question 2

A VTM tube arrives with the specimen leaked into the transport bag. What is the appropriate action?

Accepted Answer

Reject the specimen and request recollection

Answer

Leaked specimens pose contamination and safety risks and may have compromised volume or integrity.

Question 3

Which documentation is essential for buccal swabs collected for legal paternity testing?

Accepted Answer

A chain-of-custody form

Answer

Chain of custody documents every transfer so the results are legally defensible.

Question 4

Why should buccal swabs be air-dried before packaging when no transport medium is used?

Accepted Answer

To prevent bacterial and mold growth that can degrade DNA

Answer

Moisture in a sealed package promotes microbial growth that degrades DNA.

Question 5

Which blood component is a well-recognized PCR inhibitor if carried through extraction?

Accepted Answer

Heme

Answer

Heme from hemoglobin inhibits DNA polymerase, so hemolyzed samples can be problematic.

PCR - Polymerase Chain Reaction Certification Practice Test