AACC AACC Instrumentation & Technology

Question 1

Which detection principle is used in most automated clinical chemistry analyzers to measure the concentration of an analyte based on light absorption?

Accepted Answer

Spectrophotometry

Answer

Fluorometry

Answer

Nephelometry

Answer

Electrochemiluminescence

Question 2

In immunoassay analyzers, what does the term 'hook effect' (or 'high-dose hook effect') refer to?

Accepted Answer

A falsely low result caused by an extremely high concentration of analyte saturating both capture and detection antibodies

Answer

A mechanical failure in the probe arm

Answer

A cross-reactivity between two structurally similar analytes

Answer

An instrument error during pipetting of calibrators

Question 3

What is the purpose of a daily linearity check on a clinical chemistry analyzer?

Accepted Answer

To verify that the analyzer can accurately measure analyte concentrations across its full reportable range

Answer

To test the analyzer's pipetting speed

Answer

To confirm reagent lot compatibility

Answer

To assess analyzer downtime frequency

Question 4

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

Accepted Answer

Glass pH electrode

Answer

Clark electrode

Answer

Severinghaus electrode

Answer

Ion-selective electrode for sodium

Question 5

In mass spectrometry-based clinical assays (LC-MS/MS), what is the role of the internal standard?

Accepted Answer

To correct for variations in sample preparation, ionization efficiency, and instrument response

Answer

To calibrate the ion source voltage

Answer

To identify the molecular formula of unknown compounds

Answer

To measure total protein in the sample

Question 6

What does the term 'carry-over' mean in the context of automated analyzer performance?

Accepted Answer

Contamination of a sample by residual analyte from a previously analyzed high-concentration sample

Answer

Transferring patient results to the electronic health record

Answer

A repeat analysis triggered by a delta check flag

Answer

Moving samples between different analyzer modules