NCMA Infection Control and Medical Asepsis 2 — Questions and Answers
Question 1: What is the difference between sterilization and disinfection in infection control?
- Sterilization destroys ALL microorganisms including spores; disinfection reduces or destroys most microorganisms but not necessarily spores (Correct answer)
- Disinfection destroys all microorganisms; sterilization only reduces bacterial counts
- Sterilization and disinfection are interchangeable terms
- Disinfection is used for surgical instruments; sterilization is used only for surfaces
Correct answer: Sterilization destroys ALL microorganisms including spores; disinfection reduces or destroys most microorganisms but not necessarily spores
Sterilization achieves complete destruction of all microorganisms, including spores, and is required for surgical instruments; disinfection kills most pathogens but may not eliminate heat-resistant spores, making it appropriate for non-critical surfaces.
The Spaulding Classification System divides items into three categories: critical (contact sterile tissue — must be sterilized), semi-critical (contact mucous membranes — high-level disinfection minimum), and non-critical (contact intact skin — low to intermediate disinfection). Autoclave steam sterilization (121°C at 15 psi for 15+ minutes) is the gold standard for critical items. Chemical sterilants (glutaraldehyde, hydrogen peroxide vapor) are used for heat-sensitive items.
Question 2: According to CDC hand hygiene guidelines, when is it MANDATORY to use soap and water rather than alcohol-based hand rub?
- When hands are visibly soiled or contaminated with blood, body fluids, or after caring for a patient with Clostridioides difficile (C. diff) (Correct answer)
- After every patient contact regardless of contamination
- Only when gloves are not available
- When entering the facility at the start of a shift
Correct answer: When hands are visibly soiled or contaminated with blood, body fluids, or after caring for a patient with Clostridioides difficile (C. diff)
Alcohol-based hand rubs are ineffective against C. difficile spores and do not remove visible organic matter; soap and water are required in these specific situations to mechanically remove organisms and contaminants.
C. difficile produces heat- and alcohol-resistant spores that require the mechanical action of soap and water to be removed from hands. Other situations requiring soap and water include: after norovirus exposure (alcohol has limited effectiveness against norovirus), after using the restroom, before eating, and when hands are visibly dirty. For all other patient contacts, WHO and CDC guidelines favor alcohol-based hand rub because it is faster, less damaging to skin, and more accessible than sinks.
Question 3: What personal protective equipment (PPE) combination is required when a medical assistant anticipates exposure to blood or body fluids during a procedure?
- Gloves at minimum; add mask/eye protection and gown when splashing or spraying is possible (Correct answer)
- No PPE is needed if the patient is not visibly ill
- Only a face mask is required for all procedures
- Gloves are optional if hands will be washed afterward
Correct answer: Gloves at minimum; add mask/eye protection and gown when splashing or spraying is possible
OSHA Bloodborne Pathogen Standard requires gloves for all procedures involving potential blood/body fluid contact, with mask, eye protection, and gown added when splashing or aerosolization is anticipated.
The hierarchy of PPE for body fluid exposure: gloves (always required for contact), plus masks and eye protection (goggles or face shield) when droplets or splashes may reach mucous membranes, plus fluid-resistant gowns when clothing is at risk of contamination. Medical assistants must don PPE before beginning the procedure (not after exposure begins), remove it in the correct sequence to prevent self-contamination (gloves off first, then gown, then face protection, then hand hygiene), and dispose of it as regulated medical waste.
Question 4: What is the purpose of the autoclave biological indicator (spore test)?
- To verify that the autoclave achieved conditions sufficient to kill the most resistant microorganisms (Geobacillus stearothermophilus spores) (Correct answer)
- To measure the temperature inside the autoclave during sterilization
- To indicate that the wrapping paper was the correct color after sterilization
- To count the number of instruments in each load
Correct answer: To verify that the autoclave achieved conditions sufficient to kill the most resistant microorganisms (Geobacillus stearothermophilus spores)
Biological indicators contain strips or vials of Geobacillus stearothermophilus spores — the most heat-resistant organisms used as a benchmark; if incubation after the cycle shows no growth, sterilization was successful.
Three types of indicators are used in sterilization monitoring: mechanical (gauges, time-temperature printouts), chemical (autoclave tape or chemical strips that change color when exposed to steam), and biological (spore tests). Only biological indicators directly test whether the sterilization process was lethal to the most resistant organisms. AAMI and CDC recommend running biological indicators at least weekly (many facilities run them with every load). A positive spore test means the load must be recalled.
Question 5: Which transmission-based precaution category is used for tuberculosis (TB)?
- Airborne precautions (N95 respirator, negative pressure room) (Correct answer)
- Droplet precautions (surgical mask, private room)
- Contact precautions (gown and gloves)
- Standard precautions only
Correct answer: Airborne precautions (N95 respirator, negative pressure room)
TB is transmitted via small airborne particles (droplet nuclei <5 microns) that remain suspended in air for extended periods; airborne precautions including N95 respirator and negative-pressure isolation room are required.
The three transmission-based precaution categories are: airborne (TB, measles, varicella — requires N95 respirator and negative-pressure room), droplet (influenza, COVID-19, pertussis — requires surgical mask within 3 feet), and contact (MRSA, C. diff, scabies — requires gown and gloves). Standard precautions apply to ALL patients regardless of diagnosis and include hand hygiene, PPE for body fluid exposure, respiratory hygiene, and safe sharps handling. Medical assistants must know when to apply each category.
Question 6: What does the term 'fomite' mean in the context of infection control?
- An inanimate object that can harbor and transmit infectious organisms (e.g., doorknobs, stethoscopes, examination tables) (Correct answer)
- A type of airborne pathogen
- A chemical used to disinfect surfaces
- A personal protective equipment item
Correct answer: An inanimate object that can harbor and transmit infectious organisms (e.g., doorknobs, stethoscopes, examination tables)
A fomite is any inanimate object (surface or equipment) that becomes contaminated with infectious agents and can serve as an indirect transmission vehicle between patients or between patients and healthcare workers.
Common healthcare fomites include: blood pressure cuffs, stethoscopes, examination table surfaces, computer keyboards, door handles, and mobile phones. Studies have shown MRSA, C. diff, and VRE surviving on inanimate surfaces for weeks to months. Infection control measures against fomite transmission include: cleaning and disinfecting all shared equipment between patients, using disposable covers on reusable equipment, and prohibiting personal mobile devices in clinical areas or disinfecting them regularly.
NCMA Infection Control and Medical Asepsis 2
What is the difference between sterilization and disinfection in infection control?