Molecular Diagnostics Flashcards
7 cards from real CSMLS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Molecular Diagnostics flashcards as text
What is the purpose of an internal control in a molecular diagnostic assay?
Answer: To detect PCR inhibition and confirm successful nucleic acid extraction
An internal control is co-extracted and co-amplified with the clinical sample; if it fails to amplify, this indicates either extraction failure or PCR inhibition, preventing false-negative reporting.
High-resolution melt (HRM) analysis detects sequence variants by monitoring:
Answer: Changes in the melting profile of PCR products as they are heated
HRM monitors the decrease in fluorescence as double-stranded PCR product is denatured by increasing temperature; mutations alter base pairing and change the shape or temperature of the melt curve compared to wild-type.
Loop-mediated isothermal amplification (LAMP) is advantageous over PCR in resource-limited settings because:
Answer: It amplifies target DNA at a constant temperature without thermal cycling equipment
LAMP amplifies target DNA at a constant 60–65°C using 4–6 primers recognizing 6–8 target regions, eliminating the need for a thermocycler and making it suitable for point-of-care or field testing.
Multiplex PCR panels used in clinical microbiology laboratories are designed to:
Answer: Simultaneously detect multiple pathogens in a single reaction
Multiplex PCR includes multiple primer sets targeting different pathogens, allowing simultaneous detection of panels such as respiratory viruses or gastrointestinal pathogens from a single patient specimen.
In clinical transplantation, high-resolution HLA typing is most accurately performed by:
Answer: Sequence-based typing (SBT) or PCR-SSO
Sequence-based typing (SBT) and PCR with sequence-specific oligonucleotide probes (PCR-SSO) provide allele-level resolution of HLA genes, enabling precise matching of donors and recipients in transplantation.
Analytical sensitivity in a molecular diagnostic test refers to:
Answer: The lowest concentration of target nucleic acid reliably detected above background
Analytical sensitivity, often expressed as the limit of detection (LoD), is the smallest quantity of target that can be consistently detected; it is distinct from clinical sensitivity, which describes performance in the patient population.
The negative predictive value (NPV) of a molecular diagnostic test describes:
Answer: The probability that a negative result correctly means the patient is disease-free
NPV is the probability that a patient with a negative test result truly does not have the condition; it is influenced by both the specificity of the test and the prevalence of the disease in the tested population.