Medical Laboratory Technician Laboratory Operations and Safety Questions and Answers — Questions and Answers
Question 1: A medical laboratory technician accidentally drops and breaks a culture plate of Mycobacterium tuberculosis on the floor outside of a biological safety cabinet. What is the FIRST and most critical action to take?
- Immediately cover the spill with paper towels.
- Pour a 10% bleach solution directly onto the spill.
- Evacuate the room and notify the supervisor. (Correct answer)
- Begin cleaning the spill with a tuberculocidal disinfectant.
Correct answer: Evacuate the room and notify the supervisor.
The primary hazard from a Mycobacterium tuberculosis spill is the generation of infectious aerosols. The most critical first step is to remove all personnel from the area to prevent inhalation. The room should be closed off and the supervisor notified so that proper BSL-3 spill response procedures can be initiated, which includes allowing aerosols to settle for at least 30 minutes before re-entry and cleanup.
Question 2: When reviewing a Levey-Jennings chart for a quality control material, a technician notes that the last seven consecutive data points are all on the same side of the mean. This pattern is best described as a:
- Shift (Correct answer)
- Trend
- Random error
- 1_3s violation
Correct answer: Shift
A 'shift' is a type of systematic error observed on a Levey-Jennings chart when six or more consecutive control values fall on the same side of the mean. This indicates an abrupt change in the testing system, such as a new lot of reagents or a change in instrument calibration.
Question 3: Which of the following is a key requirement of the OSHA Bloodborne Pathogens Standard that employers must provide to at-risk laboratory employees?
- Annual proficiency testing for all performed tests.
- A detailed Chemical Hygiene Plan for the laboratory.
- The Hepatitis B vaccine at no cost to the employee. (Correct answer)
- Classification of all laboratory tests into complexity categories.
Correct answer: The Hepatitis B vaccine at no cost to the employee.
The OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030) mandates that employers must make the Hepatitis B vaccination series available, free of charge, to all employees who have occupational exposure to blood or other potentially infectious materials. The Chemical Hygiene Plan is required by the OSHA Laboratory Standard, while proficiency testing and test complexity are governed by CLIA.
Question 4: A phlebotomist needs to draw specimens for coagulation studies (light blue top), a complete blood count (lavender top), and a chemistry panel requiring serum (gold top SST). According to CLSI guidelines, what is the correct order of draw?
- Light blue, Gold, Lavender (Correct answer)
- Gold, Lavender, Light blue
- Lavender, Light blue, Gold
- Light blue, Lavender, Gold
Correct answer: Light blue, Gold, Lavender
The correct CLSI order of draw for these tubes is: 1) Light blue (sodium citrate) for coagulation tests, 2) Gold/SST (serum tube with clot activator/gel), and 3) Lavender (EDTA). This order prevents contamination of the coagulation sample with clot activators or anticoagulants like EDTA, which would severely compromise the test results.
Question 5: The National Fire Protection Association (NFPA) 704 diamond provides a rapid visual representation of a chemical's hazards. What type of hazard is indicated by the blue quadrant?
- Flammability
- Health (Correct answer)
- Instability/Reactivity
- Special Hazard
Correct answer: Health
The NFPA 704 diamond is color-coded for specific hazards: the blue quadrant represents health hazards, red indicates flammability, yellow denotes instability (reactivity), and the white quadrant is used for special hazards (e.g., water-reactive, oxidizer).
Question 6: A technologist must prepare a 1:5 dilution of a patient's serum in saline to perform a test. If the final volume needed is 1.0 mL (1000 µL), how much patient serum should be used?
- 100 µL
- 500 µL
- 800 µL
- 200 µL (Correct answer)
Correct answer: 200 µL
A 1:5 dilution means 1 part solute (serum) plus 4 parts diluent (saline) for a total of 5 parts. To calculate the amount of serum needed, divide the final volume by the dilution factor: 1000 µL / 5 = 200 µL. The technologist would then add 800 µL of saline to the 200 µL of serum to achieve the final volume of 1000 µL.
Medical Laboratory Technician Laboratory Operations and Safety Questions and Answers
A medical laboratory technician accidentally drops and breaks a culture plate of Mycobacterium tuberculosis on the floor outside of a biological safety cabinet.
What is the FIRST and most critical action to take?