Laboratory Safety
What this domain tests
Laboratory safety questions ask you to apply standard precautions, chemical handling, fire response and biomedical waste segregation in a small clinical laboratory. Expect scenario items, not just definitions.
Core rules
- Treat every blood and body-fluid sample as infectious. Wear gloves, a lab coat and eye protection; tie back hair; wear closed footwear. Do not eat, drink, smoke or mouth-pipette in the laboratory.
- Segregate waste at the point of generation. Soiled absorbent material and blood-contaminated disposable items go into the yellow infectious-waste stream; contaminated recyclable plastic such as tubing goes into red; needles and blades go into a puncture-proof white sharps container; broken glass goes into blue.
- For a chemical splash, flush with running water for at least 15 minutes and use the eyewash or safety shower. Read the safety data sheet before handling a new reagent.
- For fire, raise the alarm, evacuate, and use a PASS extinguisher only if trained: Pull the pin, Aim at the base, Squeeze, Sweep.
- Clean blood spills by absorbing the bulk, covering the area with 1% sodium hypochlorite for about 10 minutes, then wiping and discarding the absorbent as infectious waste.
Worked example
A tube breaks on the bench and 2 mL of blood spreads. Put on gloves and eye protection, restrict the area, absorb the liquid with paper towels, cover the spot with 1% hypochlorite for 10 minutes, wipe from the outside inward, discard the towels as yellow waste, and disinfect the bench again. Reasoning: the spill is both infectious and sharps-contaminated; alcohol alone evaporates too quickly and fixes protein, so hypochlorite is preferred for blood.
Traps
- Using 70% alcohol as the only blood-spill disinfectant.
- Putting needles into a red bag or recapping them by hand.
- Treating autoclave tape as proof of sterilization; it only shows the load was processed.
- Adding water to concentrated acid instead of acid to water.