Medical Laboratory Technician Exam Medical Laboratory Technician Laboratory Operations and Safety 1 — Questions and Answers
Question 1: Which color-coded biohazard bag is universally used in clinical laboratories for the disposal of regulated medical waste that may contain bloodborne pathogens?
- Blue bag with white lettering
- Red or orange bag with the biohazard symbol (Correct answer)
- Yellow bag with a radiation trefoil
- Clear bag with a chemical hazard label
Correct answer: Red or orange bag with the biohazard symbol
Red or orange bags bearing the biohazard symbol are required by OSHA's Bloodborne Pathogen Standard (29 CFR 1910.1030) for disposal of regulated medical waste such as contaminated gloves, gauze, and culture materials that may contain bloodborne pathogens.
Question 2: A laboratory employee accidentally splashes an unknown chemical reagent into their eyes. What is the immediate first action that should be taken?
- Consult the Safety Data Sheet to identify the chemical before acting
- Notify the supervisor and wait for instructions
- Flush the eyes at the eyewash station with water for at least 15 minutes (Correct answer)
- Apply a neutralizing solution recommended by the chemical manufacturer
Correct answer: Flush the eyes at the eyewash station with water for at least 15 minutes
Immediate, continuous flushing of the eyes with water for a minimum of 15 minutes at an eyewash station is the correct first response to a chemical eye splash. Delaying action to consult an SDS or await instructions can worsen injury.
Question 3: Which type of fire extinguisher is appropriate for a Class B fire involving flammable liquids such as ethanol or acetone in a laboratory?
- Class A water extinguisher
- Class C carbon dioxide extinguisher only
- Class ABC dry chemical or Class BC carbon dioxide extinguisher (Correct answer)
- Class D dry powder extinguisher
Correct answer: Class ABC dry chemical or Class BC carbon dioxide extinguisher
Class B fires involve flammable liquids. A Class ABC dry chemical extinguisher or a Class BC carbon dioxide (CO₂) extinguisher are appropriate for these fires. A water extinguisher (Class A) can spread flammable liquids, and a Class D extinguisher is reserved for combustible metals.
Question 4: In a clinical laboratory, the Globally Harmonized System (GHS) requires that chemical containers be labeled with which standardized pictogram to indicate an acute toxic hazard?
- Flame over a circle
- Skull and crossbones (Correct answer)
- Exclamation mark
- Health hazard (silhouette with starburst on chest)
Correct answer: Skull and crossbones
Under the GHS (adopted by OSHA as the Hazard Communication Standard), the skull and crossbones pictogram indicates acute toxicity (Categories 1–3), warning of substances that are fatal or toxic in small quantities. The exclamation mark is used for lower-level hazards such as skin or eye irritants.
Question 5: A laboratory technician prepares to centrifuge a sample and notices a small crack in the centrifuge tube. What is the correct action?
- Reinforce the crack with laboratory tape before centrifuging
- Reduce centrifuge speed by 50% to minimize stress on the tube
- Replace the cracked tube with an intact tube before centrifuging (Correct answer)
- Proceed only if the crack is less than 2 mm in length
Correct answer: Replace the cracked tube with an intact tube before centrifuging
A cracked centrifuge tube must be discarded and replaced before use. Centrifugation generates enormous mechanical forces; a cracked tube can shatter, creating an aerosol of potentially infectious or hazardous material and damaging the centrifuge rotor.
Question 6: Under OSHA's Hazard Communication Standard, employees who work with hazardous chemicals must receive training on SDS interpretation and proper chemical handling. How frequently must this training be repeated when a new chemical hazard is introduced to the workplace?
- Annually, regardless of new chemical introductions
- Only at the time of initial employment
- Before the employee works with or is potentially exposed to the new hazardous chemical (Correct answer)
- Within 30 days after the new chemical is introduced to the work area
Correct answer: Before the employee works with or is potentially exposed to the new hazardous chemical
OSHA's Hazard Communication Standard (29 CFR 1910.1200) requires that employees receive training before they work with or are potentially exposed to any new chemical hazard introduced to the workplace. Waiting up to 30 days or limiting training to initial hire would leave employees unprotected.
