PCR PCR Applications & Clinical Diagnostics 2 — Questions and Answers
Question 1: Which PCR-based method is used to quantify viral load in HIV-positive patients to monitor antiretroviral therapy effectiveness?
- Quantitative RT-PCR (Correct answer)
- Nested PCR
- Digital droplet PCR only
- Colony PCR
Correct answer: Quantitative RT-PCR
Quantitative RT-PCR measures HIV RNA copies per milliliter of plasma, providing clinicians with data to monitor viral suppression during treatment.
Question 2: In tissue typing for organ transplantation, which PCR-based approach is used to determine HLA compatibility between donor and recipient?
- Sequence-specific primer PCR (PCR-SSP) (Correct answer)
- Inverse PCR
- Overlap extension PCR
- Emulsion PCR
Correct answer: Sequence-specific primer PCR (PCR-SSP)
PCR-SSP uses primer pairs designed to amplify only specific HLA alleles, enabling rapid and accurate HLA typing for transplant matching.
Question 3: Which application of digital PCR (dPCR) gives it an advantage over qPCR for rare mutation detection in liquid biopsy samples?
- Absolute quantification without a standard curve (Correct answer)
- Faster thermal cycling speed
- Larger sample volume capacity
- Lower reagent costs
Correct answer: Absolute quantification without a standard curve
dPCR partitions the reaction into thousands of droplets, allowing absolute quantification of rare mutations without relying on a standard curve, increasing sensitivity for liquid biopsy.
Question 4: Which PCR technique is used in newborn screening programs in the US to detect mutations causing conditions like spinal muscular atrophy (SMA)?
- Multiplex ligation-dependent probe amplification (MLPA) (Correct answer)
- Rolling circle amplification
- Inverse PCR
- Asymmetric PCR
Correct answer: Multiplex ligation-dependent probe amplification (MLPA)
MLPA uses PCR amplification of ligation products to detect copy number variations and point mutations, making it suitable for newborn screening panels.
Question 5: In infectious disease surveillance, which PCR approach enables point-of-care testing by completing amplification in under 30 minutes without a thermocycler?
- Loop-mediated isothermal amplification (LAMP) (Correct answer)
- Conventional PCR
- Touchdown PCR
- Nested PCR
Correct answer: Loop-mediated isothermal amplification (LAMP)
LAMP uses a strand-displacing polymerase at a constant temperature, eliminating the need for a thermocycler and enabling rapid point-of-care diagnostic use.
Question 6: Which PCR-based diagnostic test is used in US clinical labs to differentiate influenza A, influenza B, and RSV in respiratory specimens from a single sample?
- Multiplex real-time RT-PCR panel (Correct answer)
- Single-plex endpoint PCR
- Pyrosequencing
- Southern blot hybridization
Correct answer: Multiplex real-time RT-PCR panel
Multiplex real-time RT-PCR panels allow simultaneous detection and differentiation of multiple respiratory viruses from one specimen, improving turnaround time and resource efficiency.
PCR PCR Applications & Clinical Diagnostics 2
Which PCR-based method is used to quantify viral load in HIV-positive patients to monitor antiretroviral therapy effectiveness?