Infection Control: Standard Precautions, Transmission-Based Precautions, and Hand Hygiene

Why Infection Control Matters

Healthcare-associated infections (HAIs) are infections that patients acquire while receiving care for another condition. They can prolong hospital stays, increase antimicrobial resistance, and cause serious harm. Many HAIs are preventable when every member of the care team consistently follows evidence-based practices.

The foundational U.S. guidance is the CDC and Healthcare Infection Control Practices Advisory Committee (HICPAC) Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings (2007, with later updates). It organizes precautions into two tiers: Standard Precautions, used for all patients, and Transmission-Based Precautions, added for patients known or suspected to be infected or colonized with certain pathogens.

Infection transmission is often described as a chain: an infectious agent, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Each precaution in this module is designed to break one or more links in that chain.

Standard Precautions

Standard Precautions are based on the principle that all blood, body fluids, secretions, excretions (except sweat), non-intact skin, and mucous membranes may contain transmissible infectious agents. They apply to every patient, in every setting, regardless of suspected or confirmed diagnosis. CDC lists the following core elements:

• Hand hygiene at the appropriate moments of care.
• Personal protective equipment (PPE) selected according to the anticipated exposure, such as gloves for contact with blood or body fluids, and gowns, masks, and eye protection when splashes or sprays are likely.
• Respiratory hygiene and cough etiquette, including covering coughs, offering masks to coughing patients, and spatial separation in waiting areas when possible.
• Safe injection practices: one needle, one syringe, one time; use single-dose vials for one patient only; never enter a vial with a used needle or syringe.
• Sharps safety, using engineering controls and never recapping used needles with a two-handed technique.
• Safe handling of potentially contaminated equipment and surfaces, including cleaning and disinfecting reusable equipment between patients.
• Environmental cleaning of high-touch surfaces using EPA-registered disinfectants according to label instructions.

Standard Precautions also include using masks for procedures such as lumbar punctures, where oropharyngeal droplets could contaminate a sterile field.

Hand Hygiene

Hand hygiene is the single most important measure for preventing the spread of infection in healthcare. CDC's Hand Hygiene in Healthcare Settings guidance and the World Health Organization's My 5 Moments for Hand Hygiene describe when to clean hands:

• Before touching a patient.
• Before a clean or aseptic procedure.
• After body fluid exposure risk.
• After touching a patient.
• After touching patient surroundings.

CDC also recommends hand hygiene after removing gloves. Gloves are not a substitute for hand hygiene.

Alcohol-based hand rub (ABHR) is the preferred method in most clinical situations because it is effective against many pathogens, is faster, and is generally gentler on skin. Apply enough product to cover all surfaces of the hands and rub until dry.

Soap and water should be used when hands are visibly soiled, before eating, after using the restroom, and when caring for patients with known or suspected infectious diarrhea such as Clostridioides difficile or norovirus, because alcohol is less effective against spores and some non-enveloped viruses. CDC instructs rubbing hands with soap for at least 15 seconds, rinsing, and drying with a disposable towel.

Keep natural nails short and avoid artificial nails when providing direct patient care, as recommended by CDC and WHO.

Transmission-Based Precautions

Transmission-Based Precautions are used in addition to Standard Precautions when a patient is known or suspected to be infected or colonized with agents that spread by specific routes.

• Contact Precautions are used for organisms spread by direct or indirect contact, such as many multidrug-resistant organisms and C. difficile. Wear a gown and gloves on room entry, use dedicated or disposable equipment when possible, and place the patient in a single room when available.
• Droplet Precautions are used for pathogens spread by respiratory droplets generated by coughing, sneezing, or talking, such as influenza and pertussis. Wear a facemask on room entry, place the patient in a single room when available, and have the patient wear a mask during transport.
• Airborne Precautions are used for agents that remain infectious over long distances when suspended in air, such as tuberculosis, measles, and varicella. Place the patient in an airborne infection isolation room (AIIR) with negative pressure, keep the door closed, and wear a fit-tested NIOSH-approved N95 or higher-level respirator.

Some pathogens require combined precautions; for example, CDC recommends Airborne plus Contact Precautions for disseminated varicella. Always follow your facility's isolation signage and infection prevention team.

Donning and Doffing PPE

CDC's PPE sequence guidance helps reduce self-contamination. Select PPE based on the anticipated exposure and the precautions in place.

Typical donning sequence:

• Gown
• Mask or respirator (perform a user seal check for respirators)
• Goggles or face shield
• Gloves, extended to cover the gown cuffs

Typical removal sequence:

• Gloves (the outside is considered most contaminated)
• Goggles or face shield, handled by the head band or ear pieces
• Gown, rolled inside-out away from the body
• Mask or respirator, removed by the ties or elastics without touching the front, after leaving the patient room when a respirator is used

CDC also describes an acceptable alternative in which the gown and gloves are removed together. In every approach, perform hand hygiene immediately after removing all PPE, and also any time hands become contaminated during removal.

Equipment, Environment, and Specimen Handling

The Spaulding classification, referenced in CDC's Guideline for Disinfection and Sterilization in Healthcare Facilities, guides reprocessing:

• Critical items that enter sterile tissue or the vascular system, such as surgical instruments, require sterilization.
• Semi-critical items that contact mucous membranes or non-intact skin, such as some endoscopes, require at least high-level disinfection.
• Non-critical items that contact intact skin, such as blood pressure cuffs, require low-level disinfection.

Follow the disinfectant's label for contact (wet) time. Laboratory and phlebotomy staff should transport specimens in leak-proof containers and follow the facility's biosafety practices. Clean and disinfect shared equipment, including phlebotomy trays and point-of-care devices, between patients.

Putting It Into Practice

Infection prevention is a team responsibility. Practical habits include:

• Checking isolation signage before entering any room.
• Keeping ABHR available at the point of care.
• Speaking up, respectfully, when you observe a missed hand hygiene opportunity.
• Staying home or following occupational health guidance when you are ill.
• Keeping recommended vaccinations, such as annual influenza vaccination, up to date per CDC recommendations for healthcare personnel.

For the most current guidance, consult CDC's Infection Control resources, your facility's infection prevention program, and applicable state health department requirements.