Medical Technologist Test Medical Technologist General Information 5 — Questions and Answers
Question 1: Which chain of custody procedure is MOST critical when handling forensic or medicolegal specimens?
- Processing specimens faster than routine samples
- Documenting every person who handled the specimen with time and date (Correct answer)
- Storing specimens at -80°C immediately upon receipt
- Running duplicate testing on all forensic samples
Correct answer: Documenting every person who handled the specimen with time and date
Chain of custody requires continuous documentation of every individual who handled the specimen to ensure legal admissibility of results.
Question 2: A laboratory's accuracy is BEST evaluated by:
- Calculating the coefficient of variation from repeated measurements
- Participating in external proficiency testing programs (Correct answer)
- Performing duplicate testing on 10% of all specimens
- Comparing results to internal QC mean values
Correct answer: Participating in external proficiency testing programs
External proficiency testing (PT) compares a laboratory's results to peer laboratories and reference values, providing an objective assessment of accuracy.
Question 3: Pre-analytical variables that can affect laboratory test results include all of the following EXCEPT:
- Patient fasting status
- Specimen transport temperature
- Instrument calibration frequency (Correct answer)
- Tourniquet application time
Correct answer: Instrument calibration frequency
Instrument calibration is an analytical variable occurring within the laboratory; patient status, transport, and collection technique are pre-analytical variables.
Question 4: Which of the following correctly describes the difference between sensitivity and specificity of a laboratory test?
- Sensitivity = ability to detect true negatives; specificity = ability to detect true positives
- Sensitivity = ability to detect true positives (diseased); specificity = ability to detect true negatives (healthy) (Correct answer)
- Sensitivity measures precision; specificity measures accuracy
- Sensitivity applies to qualitative tests; specificity applies to quantitative tests
Correct answer: Sensitivity = ability to detect true positives (diseased); specificity = ability to detect true negatives (healthy)
Sensitivity (true positive rate) reflects a test's ability to correctly identify diseased individuals; specificity (true negative rate) reflects identification of healthy individuals.
Question 5: The principle of atomic absorption spectrophotometry (AAS) is based on:
- Emission of light by excited atoms returning to ground state
- Absorption of specific wavelengths of light by ground-state atoms (Correct answer)
- Scattering of light by particles in suspension
- Fluorescence emission after ultraviolet excitation
Correct answer: Absorption of specific wavelengths of light by ground-state atoms
AAS measures the amount of light absorbed by free ground-state atoms at a wavelength specific to each element, enabling quantification of metals like lead or copper.
Question 6: When a laboratory implements a new test, which validation step confirms the test's ability to detect low concentrations of analyte?
- Linearity verification
- Limit of detection (LoD) determination (Correct answer)
- Interference testing
- Reference interval transference
Correct answer: Limit of detection (LoD) determination
The limit of detection (LoD) establishes the lowest analyte concentration reliably distinguished from blank/noise with a defined statistical confidence.
Question 7: According to OSHA's Bloodborne Pathogen Standard, which of the following is required for laboratory personnel?
- Annual fit-testing for N95 respirators
- Hepatitis B vaccination offered at no cost to the employee (Correct answer)
- Mandatory HIV testing after employment begins
- Wearing full PPE for all clerical tasks in the laboratory
Correct answer: Hepatitis B vaccination offered at no cost to the employee
OSHA's Bloodborne Pathogens Standard (29 CFR 1910.1030) requires employers to offer Hepatitis B vaccination at no cost to all at-risk employees.
Medical Technologist Test Medical Technologist General Information 5
Which chain of custody procedure is MOST critical when handling forensic or medicolegal specimens?