AACC Laboratory Instrumentation & Technology Flashcards

Which detector is most commonly used in high-performance liquid chromatography (HPLC) for measuring UV-absorbing analytes in clinical chemistry?

Answer: UV-Vis spectrophotometric detector

UV-Vis spectrophotometric detectors are the most widely used in HPLC for clinical analytes that absorb ultraviolet or visible light.

What is the primary purpose of an internal standard in mass spectrometry-based clinical assays?

Answer: To correct for ion suppression and instrument variability

Internal standards compensate for matrix effects such as ion suppression and variations in instrument response, improving quantitative accuracy.

In a clinical chemistry analyzer, what does a reagent blank correct for?

Answer: Absorbance contributed by the reagent itself

A reagent blank measures the absorbance of reagents without sample, allowing the analyzer to subtract this background from patient readings.

Which ionization technique is considered 'soft' and is commonly used for large biomolecules in clinical mass spectrometry?

Answer: Electrospray ionization (ESI)

Electrospray ionization is a soft ionization method that produces intact molecular ions, making it ideal for proteins, peptides, and other large biomolecules.

What is carryover in automated clinical analyzers?

Answer: Contamination of one sample by a preceding high-concentration sample

Carryover occurs when residual analyte from a high-concentration sample contaminates the subsequent sample, causing falsely elevated results.

In flow cytometry used in clinical laboratories, what physical property is measured by the side scatter (SSC) signal?

Answer: Cell granularity and internal complexity

Side scatter reflects light at approximately 90° and correlates with the internal complexity and granularity of a cell.