Instrumentation & Technology Applications Flashcards

A clinical laboratory implementing a new multiplex immunoassay panel for respiratory pathogens must establish which performance characteristic to ensure the assay does not misidentify a co-infection as a single pathogen?

Answer: Analytical specificity and cross-reactivity profile among panel targets

Multiplexed assays must demonstrate adequate analytical specificity, confirming that each target's signal channel does not cross-react with other panel organisms or common respiratory pathogens.

In a clinical laboratory using tandem mass spectrometry for newborn screening, the measurement of acylcarnitine profiles relies on which ionization method?

Answer: Electrospray ionization (ESI)

Electrospray ionization is the standard ionization method for newborn screening acylcarnitine profiling because it is a soft ionization technique compatible with dried blood spot extracts and produces multiply charged ions suitable for triple-quadrupole MS.

A laboratory consultant reviewing delta check failures observes a pattern of specimen mix-ups between patient samples. Which LIS configuration BEST prevents this error type?

Answer: Automated specimen identity verification using barcode scanning at every pre-analytical step

Barcode-based specimen verification at each pre-analytical step (accession, aliquot, load) closes the identification gap that allows mix-ups to occur before the analyzer flags discordant results.

Which type of electrode is used in most modern blood gas analyzers to measure pH?

Answer: Glass pH electrode with a silver/silver chloride reference electrode

Blood gas analyzers use a glass pH electrode, which generates a potential difference proportional to hydrogen ion activity, referenced against a silver/silver chloride electrode.

A laboratory has acquired a MALDI-TOF mass spectrometer for microbial identification. The system identifies organisms by:

Answer: Matching the unique protein spectral fingerprint of the organism to a reference database

MALDI-TOF generates a unique mass spectrum (primarily from ribosomal proteins) for each organism, which is compared against a database of reference spectra to identify the microorganism.

When a laboratory consultant evaluates carryover in a continuous-flow chemistry analyzer, which sample sequence is used for the classic carryover experiment?

Answer: Three high-concentration samples followed by three low-concentration samples of the same analyte

The standard carryover experiment uses three high-concentration specimens (H1, H2, H3) immediately followed by three low-concentration specimens (L1, L2, L3) to calculate carry-over as (L1−L3)/(H3−L3) × 100%.

In laboratory robotics, a 'gripper' system for tube handling must be validated for which critical parameter specific to specimen integrity?

Answer: Applied grip force to prevent tube cracking or sample hemolysis from mechanical stress

Excessive grip force on primary tubes can crack or crush the tube, while inadequate force causes drops; mechanical stress can also induce hemolysis, compromising specimen integrity.