3.1 Infection Control and Standard Precautions

The Chain of Infection

Infection prevention is the largest single safety topic on the California Certified Nursing Assistant (CNA) exam, so you must understand HOW infection spreads before you can stop it. The Centers for Disease Control and Prevention (CDC) describes the spread of disease as a chain of infection with six links:

1. Infectious agent — the pathogen (bacteria, virus, fungus, or parasite) that causes disease.
2. Reservoir — where the pathogen lives and grows: people, animals, food, water, soil, or contaminated equipment.
3. Portal of exit — how the pathogen leaves the reservoir (nose, mouth, broken skin, blood, stool, drainage).
4. Mode of transmission — how it travels: direct contact, indirect contact (touching a contaminated object), droplet, or airborne.
5. Portal of entry — how it enters a new host (broken skin, mucous membranes, respiratory tract, catheters and tubes).
6. Susceptible host — a person at risk. The elderly, the very young, and people who are immunocompromised or have invasive devices are most vulnerable.

The key exam concept: if you break any single link, the infection cannot spread. Hand hygiene breaks the mode of transmission link, which is why it matters most.

Medical Asepsis and Hand Hygiene

Medical asepsis, also called clean technique, is the practice of reducing the number of pathogens and preventing their spread. Routine CNA tasks — bathing, feeding, bed making, vital signs — use medical asepsis. (Surgical asepsis, or sterile technique, makes an area completely free of all microorganisms and is used for invasive procedures; it is generally outside the CNA scope.)

Hand hygiene is the single most important way to prevent the spread of infection. Wash your hands:

• Before and after every resident contact
• Before putting on and after removing gloves
• After using the restroom, coughing, or sneezing
• Whenever hands are visibly soiled

Handwashing technique tested on the exam:

Alcohol-based hand sanitizer is acceptable when hands are not visibly soiled, but you must use soap and water when hands are visibly dirty and after caring for a resident with Clostridioides difficile (C. diff), because alcohol does not kill its spores.

Standard Precautions and PPE

Standard Precautions are used with EVERY resident, every time, regardless of diagnosis. They assume that the blood, all body fluids (except sweat), non-intact skin, and mucous membranes of every person may carry infection. Standard Precautions include hand hygiene, personal protective equipment (PPE), safe handling of sharps and linens, and respiratory hygiene (cough etiquette).

When to use each PPE item:

• Gloves — whenever you may touch blood, body fluids, mucous membranes, non-intact skin, or contaminated items (perineal care, emptying a bedpan, oral care).
• Gown — when clothing may be soiled or splashed by body fluids.
• Mask and goggles/face shield — when splashing or spraying of fluids to the face is likely (suctioning, irrigation).

Donning (Putting On) and Doffing (Removing) Order

The CDC sequence is heavily tested. Memorize both directions:

Hand hygiene is performed before donning and again as the LAST step after doffing. Gloves come off first when removing PPE because they are the most contaminated item. Never reuse gloves between residents, and never wash and reuse a single pair — change gloves and wash hands between tasks even on the same resident if you move from a dirty area to a clean one.

Glove Removal, Nosocomial Infections, and Common Traps

Removing gloves correctly keeps the contaminated outside from touching your skin. Grasp the outside of one glove at the palm and peel it down so it turns inside out; hold that balled-up glove in your still-gloved hand. Then slide the bare fingers of your free hand under the cuff of the remaining glove and peel it off over the first glove, so both end up inside out. Drop them in the proper container and wash your hands.

A healthcare-associated infection (HAI), sometimes called a nosocomial infection, is one a resident acquires while receiving care in a facility. Many HAIs are caused by multidrug-resistant organisms such as MRSA (methicillin-resistant Staphylococcus aureus) and VRE. CNAs prevent HAIs through diligent hand hygiene, correct PPE use, and clean technique.

Common exam traps to avoid:

• Wearing the same gloves to care for more than one resident — never do this.
• Touching your face, hair, phone, or a clean surface while wearing contaminated gloves.
• Thinking gloves replace handwashing — you still wash before and after wearing them.
• Forgetting that hand hygiene is the first and last step around any PPE.

Remember the guiding principle: a CNA's clean hands and consistent technique break the chain of infection more reliably than any other single action on the unit.