ISAC Laboratory Safety and Procedures 3 — Questions and Answers
Question 1: Which class of laser used in flow cytometers poses the greatest ocular risk from specular reflections even at low power?
- Class 1
- Class 2
- Class 3B (Correct answer)
- Class 4
Correct answer: Class 3B
Class 3B lasers can cause immediate eye injury from direct or specular (mirror-like) reflections and require appropriate laser safety eyewear at all times.
Question 2: When disposing of sharps used in flow cytometry sample preparation (e.g., needles for sample loading), what is the maximum fill level for a sharps container before it must be sealed?
- 50%
- 75% (Correct answer)
- 90%
- 100%
Correct answer: 75%
Sharps containers must be sealed and replaced when they reach the 75% fill line to prevent needle-stick injuries from overfilling.
Question 3: A cytometry technician is setting up a cell-sorting experiment with viable human tumor cells. Which additional safety measure is required compared to standard analytical cytometry?
- Double gloving only
- Use of a Class II Type A2 BSC and aerosol management system on the sorter (Correct answer)
- Wearing an N95 respirator in place of a surgical mask
- Performing all work in a Class III BSC
Correct answer: Use of a Class II Type A2 BSC and aerosol management system on the sorter
Cell sorting of viable human cells generates aerosols; ISAC guidelines require a Class II BSC enclosure or aerosol management system on the cell sorter.
Question 4: What does the term 'universal precautions' mean in the context of a clinical flow cytometry laboratory?
- Treating only known HIV-positive samples as infectious
- Treating all human blood and body fluid samples as potentially infectious (Correct answer)
- Wearing full PPE only when processing cancer patient samples
- Using BSL-3 practices for all patient specimens
Correct answer: Treating all human blood and body fluid samples as potentially infectious
Universal precautions require treating all human blood and body fluids as infectious regardless of the patient's known disease status.
Question 5: Which regulatory body in the United States sets the occupational exposure limits (OELs) for chemical hazards such as formaldehyde used in cytometry labs?
- CDC
- FDA
- OSHA (Correct answer)
- EPA
Correct answer: OSHA
OSHA establishes permissible exposure limits (PELs) for workplace chemicals including formaldehyde (1 ppm TWA, 2 ppm STEL).
Question 6: If a flow cytometry laboratory generates waste that is both chemically hazardous (contains methanol) and biologically contaminated, it should be managed as:
- Biohazardous waste only, with extra labeling
- Chemical waste only, sent to hazardous waste disposal
- Mixed waste requiring dual regulatory compliance (RCRA + biohazard regulations) (Correct answer)
- Regular trash if volume is under 1 liter
Correct answer: Mixed waste requiring dual regulatory compliance (RCRA + biohazard regulations)
Waste that is simultaneously chemically hazardous and biologically contaminated is classified as mixed waste and must comply with both RCRA chemical waste and biohazard disposal regulations.
Question 7: A new flow cytometer is installed in the lab. Before running patient samples, which document must operators review to understand instrument-specific laser and electrical hazards?
- The SDS for sheath fluid
- The instrument's IFU (Instructions for Use) and operator safety manual (Correct answer)
- The laboratory's general chemical hygiene plan only
- The ISAC data file standard documentation
Correct answer: The instrument's IFU (Instructions for Use) and operator safety manual
The manufacturer's IFU and operator safety manual contain instrument-specific hazard information including laser class, electrical ratings, and required PPE.
ISAC Laboratory Safety and Procedures 3
Which class of laser used in flow cytometers poses the greatest ocular risk from specular reflections even at low power?