Infection Control, Sterilization and Safety
This domain tests how infections spread in a health facility, how to break the chain, how sterilization differs from disinfection, and the safety rules for sharps, waste, spills and fire.
Core rules
- Chain of infection: infectious agent → reservoir → portal of exit → mode of transmission → portal of entry → susceptible host. Break any one link and transmission stops.
- Standard precautions apply to every patient: hand hygiene, gloves, gown, mask and eye protection, safe injection practice, sharps disposal, spill management.
- Hand hygiene: soap and water or alcohol rub for 20–30 seconds; WHO five moments - before patient contact, before an aseptic task, after body-fluid exposure risk, after patient contact, after touching patient surroundings.
- Disinfection kills most pathogens but not necessarily spores; sterilization kills all micro-organisms including spores.
- Autoclave: 121 °C at 15 psi for 15–20 minutes (moist heat). Hot-air oven: 160 °C for 2 hours. 2% glutaraldehyde for heat-sensitive items.
- Biomedical waste colour coding: yellow - human anatomical and soiled waste; red - contaminated recyclable plastic; white translucent - sharps; blue - glass and metallic implants. Fill sharps containers to three-quarters only.
- Needlestick injury: wash with soap and water (do not squeeze or milk the wound), apply antiseptic, report at once, start post-exposure prophylaxis within 2 hours, baseline HIV/HBV/HCV testing.
- Fire: RACE (rescue, alarm, confine, extinguish) and PASS for the extinguisher.
Worked example
A nurse sustains a needlestick from a patient known to be hepatitis-B positive. Reasoning: the wound is washed, not squeezed, antiseptic applied; the incident is reported immediately because hepatitis-B prophylaxis is time-critical; baseline bloods are taken and the injured worker is followed up through occupational health.
Traps that cost marks
Recapping needles; calling disinfection sterilization; expecting alcohol to kill spores; putting IV tubing into the yellow bag instead of red; using sterile packs past their expiry date.