ASCP Molecular Diagnostics 3

Question 1

Reverse transcriptase PCR (RT-PCR) begins with which enzymatic step?

Accepted Answer

Conversion of mRNA to complementary DNA (cDNA) by reverse transcriptase

Answer

DNA denaturation by helicase

Answer

Direct PCR amplification of RNA

Answer

Restriction enzyme digestion of mRNA

Question 2

Loss of heterozygosity (LOH) at a tumor suppressor gene locus typically indicates:

Accepted Answer

Deletion or mitotic recombination eliminating the wild-type allele

Answer

Gene amplification

Answer

Increased transcription factor binding

Answer

RNA splicing abnormality

Question 3

Which oncogene mutation is found in more than 90% of pancreatic adenocarcinomas?

Accepted Answer

KRAS (most commonly G12D)

Answer

BRAF V600E

Answer

ABL1 fusion

Answer

ALK rearrangement

Question 4

The International Sensitivity Index (ISI) is used to calculate the INR. What is its purpose?

Accepted Answer

To standardize PT results across different laboratories using different thromboplastin reagents

Answer

To adjust for patient hematocrit differences

Answer

To correct for heparin contamination

Answer

To measure fibrinogen concentration

Question 5

Which molecular technique provides the highest resolution for HLA allele-level typing?

Accepted Answer

Next-generation sequencing (NGS)

Answer

Serological HLA typing

Answer

Sequence-specific oligonucleotide probes (SSO) only

Answer

Complement-dependent cytotoxicity (CDC) crossmatch

Question 6

Digital PCR (dPCR) differs from real-time qPCR primarily in that dPCR:

Accepted Answer

Partitions samples into thousands of individual reactions to provide absolute copy number without a standard curve

Answer

Requires a standard curve for absolute quantification

Answer

Cannot detect rare mutations below 5% allele frequency

Answer

Uses Southern blot for final detection