AACC AACC Instrumentation & Technology 2 — Questions and Answers
Question 1: Which technology is the gold standard for measuring HbA1c in a clinical laboratory due to its high specificity and ability to separate hemoglobin variants?
- Immunoassay
- Boronate affinity chromatography
- High-performance liquid chromatography (HPLC) (Correct answer)
- Turbidimetry
Correct answer: High-performance liquid chromatography (HPLC)
HPLC is considered the gold standard for HbA1c measurement because it separates and quantifies individual hemoglobin fractions with high accuracy, including variant detection.
Question 2: In clinical laboratory automation, what is a 'track system'?
- A software module for tracking reagent expiration dates
- A conveyor-based transport system that connects multiple instruments to automate specimen routing (Correct answer)
- A bar-code verification system for patient identification
- A protocol for tracking proficiency testing shipments
Correct answer: A conveyor-based transport system that connects multiple instruments to automate specimen routing
A track system (total laboratory automation) uses conveyor belts and robotics to transport specimens between pre-analytical, analytical, and post-analytical workstations without manual handling.
Question 3: Point-of-care (POC) testing devices must meet which regulatory requirement before being used for patient testing in a US hospital?
- FDA clearance or approval for clinical use (Correct answer)
- DEA registration
- EPA environmental safety certification
- NIH research protocol approval
Correct answer: FDA clearance or approval for clinical use
POC testing devices used for clinical patient testing must be FDA-cleared or approved to demonstrate safety and effectiveness for their intended use.
Question 4: What principle does nephelometry use to measure analyte concentration in immunology and protein assays?
- Absorption of transmitted light at a fixed wavelength
- Measurement of light scattered by antigen-antibody complexes at an angle to the incident beam (Correct answer)
- Detection of emitted fluorescent light after excitation
- Measurement of electrical conductance changes
Correct answer: Measurement of light scattered by antigen-antibody complexes at an angle to the incident beam
Nephelometry quantifies antigen-antibody immune complexes by measuring the intensity of light scattered at an angle (usually 70–90°) from the incident beam.
Question 5: Which pre-analytical variable is most commonly responsible for falsely elevated serum potassium results?
- Lipemia in the sample
- Hemolysis due to improper specimen collection or handling (Correct answer)
- Prolonged sample refrigeration
- Use of a serum separator tube
Correct answer: Hemolysis due to improper specimen collection or handling
Hemolysis releases intracellular potassium from red blood cells into the serum, causing a falsely elevated potassium result that does not reflect the patient's true status.
Question 6: What is the purpose of a two-level quality control program in a clinical laboratory?
- To verify instrument maintenance schedules
- To detect both random and systematic errors by testing normal and abnormal concentration levels (Correct answer)
- To compare results between morning and afternoon shifts
- To confirm reagent lot compatibility
Correct answer: To detect both random and systematic errors by testing normal and abnormal concentration levels
Running QC at two levels (normal and abnormal) increases error detection by assessing performance across the reportable range and in clinically critical decision zones.
AACC AACC Instrumentation & Technology 2
Which technology is the gold standard for measuring HbA1c in a clinical laboratory due to its high specificity and ability to separate hemoglobin variants?