Infection Control Practice Test

Answer: D — Proper hand hygiene - either washing with soap and water for at least 20 seconds or using alcohol-based hand sanitizer - is recognized by the CDC and WHO as the single most effective measure to prevent healthcare-associated infections. While gloves, masks, and surface cleaning are important components of infection control, none of them replace the need for consistent and thorough hand hygiene. Hands are the primary vehicle for transmitting pathogens between residents, surfaces, and healthcare workers.

Answer: A — The CDC recommends scrubbing hands with soap and water for a minimum of 20 seconds - roughly the time it takes to sing the Happy Birthday song twice. This duration is necessary to physically remove and kill bacteria, viruses, and other pathogens from all surfaces of the hands including between fingers, under nails, and around the wrists. Shorter durations do not provide adequate microbial reduction. The full process (wet, lather, scrub 20 seconds, rinse, dry with paper towel) takes approximately 40-60 seconds total.

Answer: B — Alcohol-based hand sanitizer is effective for routine hand hygiene when hands are not visibly soiled, but it cannot penetrate through visible dirt, blood, or organic material. When hands are visibly dirty, contaminated with blood or body fluids, or after caring for a resident with C. difficile (whose spores are alcohol-resistant), soap and water must be used instead. The sanitizer should contain at least 60 percent alcohol and be rubbed over all hand surfaces until completely dry - approximately 20 seconds.

Answer: B — Hand hygiene must be performed at multiple critical points: before and after every resident contact, before and after performing any procedure, after removing gloves (gloves are not a substitute for handwashing as they can have microscopic tears), after contact with body fluids or contaminated surfaces, before handling food or medications, after using the restroom, and after coughing or sneezing. The WHO identifies these as the Five Moments for Hand Hygiene - a framework every healthcare worker should follow.

Answer: B — After washing, the CNA should use a clean paper towel to turn off the faucet because faucet handles are contaminated - they were touched with dirty hands before washing began. Touching the handles with clean bare hands would immediately recontaminate them, defeating the purpose of handwashing. The paper towel can also be used to open the door when exiting the bathroom. Some facilities have sensor-activated or foot-pedal faucets that eliminate this concern, but the paper towel method is the universal standard.

Answer: A — The correct CDC-recommended donning sequence is: (1) gown first (ties in back, covers the body), (2) mask or respirator (secure over nose and mouth, fit-check if N95), (3) eye protection such as goggles or face shield, and (4) gloves LAST (pulled over the cuffs of the gown to create a continuous barrier with no exposed skin at the wrists). This sequence ensures each piece builds upon the previous one for maximum coverage. Gloves go on last because they are the most likely to become contaminated first during care.

Answer: A — The correct CDC-recommended doffing sequence is: (1) gloves first (they are the most contaminated item - peel off carefully turning inside out), (2) gown (unfasten ties, pull away from body rolling it inside out so the contaminated outer surface is contained within), (3) exit the room, then (4) mask or respirator last (remove by the straps or ties only, never touching the front which is contaminated). Hand hygiene must be performed after removing gloves AND again after all PPE is removed.

Answer: C — A torn glove no longer provides a protective barrier - body fluids and pathogens can reach the skin through any opening, no matter how small. The CNA must stop what they are doing, carefully remove the torn glove (avoiding further contamination), perform thorough hand hygiene, and apply a fresh intact glove before resuming care. Continuing with a torn glove exposes both the CNA and the resident to cross-contamination. Double-gloving over a tear traps contaminants against the skin rather than removing them.

Answer: D — Gloves must be changed and hand hygiene performed between dirty and clean procedures on the same resident (for example, after perineal care and before oral care) AND between different residents. Wearing the same gloves from a dirty task to a clean task transfers pathogens from the contaminated area to the clean area - even on the same person. This concept of clean to dirty workflow is fundamental to infection control. Gloves should also be changed when they become torn, visibly soiled, or after prolonged use.

Answer: A — The chain of infection consists of six sequential links: (1) causative agent - the pathogen (bacteria, virus, fungus), (2) reservoir - where the pathogen lives and multiplies (human body, contaminated surfaces, water), (3) portal of exit - how it leaves the reservoir (respiratory secretions, blood, feces, wound drainage), (4) mode of transmission - how it travels (direct contact, droplet, airborne, vehicle), (5) portal of entry - how it enters a new host (mucous membranes, broken skin, respiratory tract), and (6) susceptible host. Hand hygiene and vaccination are methods to BREAK the chain, not links within it.

Answer: A — The mode of transmission is how pathogens travel from one host to another - breaking this link prevents the pathogen from reaching a new victim. Effective strategies include hand hygiene (removes pathogens from hands before they can be transferred), wearing appropriate PPE (creates a physical barrier against contact, droplet, and airborne transmission), environmental cleaning and disinfection (eliminates pathogens from surfaces), and proper waste disposal. These are the interventions most directly controlled by CNAs in their daily practice.

Answer: D — A susceptible host is an individual whose body defenses are weakened or compromised, making them more vulnerable to infection. Factors that increase susceptibility include advanced age, chronic diseases (diabetes, cancer, heart failure), immunosuppressive medications, malnutrition, recent surgery, invasive devices (catheters, IVs), skin breakdown, and stress. Most nursing home residents have multiple susceptibility factors, which is why strict infection control practices by CNAs are critical to protecting this highly vulnerable population.

Answer: B — The gastrointestinal (GI) tract is the portal of exit for pathogens that reside in the intestines and leave the body through feces. Examples include C. difficile, norovirus, E. coli, and Salmonella. This is why proper hand hygiene after toileting care, correct perineal cleaning technique, and careful handling of bedpans and soiled linens are essential infection control measures. Understanding portals of exit helps CNAs identify which infection control precautions are most important for specific types of infections.

Answer: B — Standard Precautions (formerly called Universal Precautions) are the baseline level of infection control that must be used with EVERY resident during EVERY encounter, regardless of whether they have a known infection or not. This is because many infections are contagious before symptoms appear, and many carriers show no symptoms at all. Standard Precautions include hand hygiene, use of PPE when exposure to blood or body fluids is anticipated, safe injection practices, respiratory hygiene, and proper handling of contaminated equipment and linens.

Answer: B — Contact Precautions are required for infections transmitted through direct physical contact with the infected person or indirect contact with contaminated surfaces, equipment, and objects in their environment. Examples include MRSA, VRE, C. difficile, scabies, and norovirus. Required PPE includes gown and gloves, which must be donned before entering the room and removed before leaving. Dedicated equipment (stethoscope, blood pressure cuff) should remain in the room to prevent cross-contamination.

Answer: C — Droplet Precautions require a surgical mask when working within 3 to 6 feet of the resident because droplets (produced by coughing, sneezing, talking) are larger particles that travel short distances and fall to the ground quickly - they do not remain suspended in the air. Examples of droplet-transmitted infections include influenza, pertussis (whooping cough), and certain types of meningitis. A surgical mask is sufficient because droplets are too large to be inhaled deeply into the lungs. An N95 respirator is only required for Airborne Precautions.

Answer: D — Airborne Precautions are the highest level of respiratory protection and require an N95 respirator (or powered air-purifying respirator/PAPR) that has been individually fit-tested to ensure a tight seal against the face. This is necessary because airborne pathogens (tuberculosis, measles, chickenpox, COVID-19 in certain procedures) produce tiny particles called droplet nuclei that remain suspended in the air for hours, travel long distances, and can be inhaled deep into the lungs. The resident must be placed in an Airborne Infection Isolation Room (AIIR) with negative air pressure.

Answer: A — Contact Precautions for MRSA require the CNA to don a gown and gloves before entering the room. The gown protects clothing and exposed skin from contact with the contaminated environment, and gloves protect the hands from direct contact with the pathogen. A mask is not required for Contact Precautions unless the resident also has a respiratory infection requiring additional precautions. Both gown and gloves must be removed inside the room (or at the doorway) before exiting, followed by immediate hand hygiene.

Answer: C — Isolation precaution requirements apply to EVERY entry into the room - there is no exception for brief visits. Even a one-minute exposure within 3 to 6 feet of a resident on Droplet Precautions is enough time to inhale infectious respiratory droplets produced by coughing, sneezing, or even talking. The CNA must don a surgical mask before entering regardless of the duration of the visit. Leaving the tray outside forces a potentially weak or unsteady resident to retrieve it unsafely, and asking an untrained staff member to enter violates safety protocols.

Answer: B — Used needles, lancets, razor blades, and other sharps must be immediately disposed of in a designated puncture-resistant sharps container located at or near the point of use. Sharps containers are rigid, leak-proof, clearly labeled with the biohazard symbol, and designed to prevent needlestick injuries. Needles should NEVER be recapped, bent, broken, or removed from syringes before disposal. Needlestick injuries expose healthcare workers to bloodborne pathogens including HIV, Hepatitis B, and Hepatitis C.

Answer: D — Soiled linens should be handled as little as possible, never shaken (shaking releases pathogens into the air), held away from the CNA uniform and body, rolled with the most soiled area to the inside, and placed directly into the designated linen bag or hamper at the point of use. Soiled linens should never be placed on the floor, carried against the body, sorted at the bedside, or transported through hallways without being bagged. These precautions prevent the spread of pathogens through airborne particles, direct contact, and environmental contamination.

Answer: C — Items saturated or dripping with blood or other potentially infectious materials (OPIM) must be disposed of in red biohazard bags or containers that are clearly marked with the universal biohazard symbol. This includes heavily soiled dressings, blood-soaked materials, and items contaminated with body fluids. These containers are specially handled, transported, and incinerated or treated according to regulatory standards. Placing biohazardous waste in regular trash exposes housekeeping staff, waste handlers, and the community to dangerous pathogens.

Answer: C — A sterile field is a designated area that is completely free from all microorganisms - including bacteria, viruses, fungi, and spores. It is created using sterilized supplies (autoclaved instruments, sterile drapes, sterile gloves) and must be maintained through strict technique to prevent contamination. Any item or area that has been touched by a non-sterile surface is considered contaminated and can no longer be used in the sterile field. Sterile technique is used during wound care, catheter insertion, and other invasive procedures.

Answer: C — Reaching across or over a sterile field with non-sterile hands, arms, or clothing is one of the most common causes of contamination - microorganisms can fall from skin, hair, or clothing onto the sterile surface below. If an item is needed on the far side of the sterile field, the CNA should walk around to the other side rather than reaching over. Other rules include never turning your back to a sterile field (you cannot monitor what you cannot see), keeping sterile items above waist level, and considering any item below the waist or table edge to be contaminated.

Answer: D — If a sterile package has any breach in its integrity - including tears, punctures, moisture, discoloration, or an expired sterilization date - the contents must be considered contaminated and the entire package must be discarded and replaced with a new one. Sterility cannot be guaranteed once the protective barrier has been compromised, even if the tear appears small or the inner contents look undamaged. Using a compromised sterile package during a procedure introduces microorganisms directly into a wound or body cavity, potentially causing serious infection.