CT(IAC) Exam key terms

The proportion of people exposed to an infectious agent who become ill during a defined period, calculated as new cases divided by the population at risk. Used in outbreak settings to compare risk across exposure groups.

A standard set of clinical, laboratory, and epidemiologic criteria used to decide whether a person counts as having a particular condition. It must be applied consistently so cases can be counted and compared.

The number of new cases of a condition arising in a population over a specified time, divided by the population at risk. It measures how quickly new infections appear rather than how many exist overall.

The total number of existing cases of a condition in a population at a given point or period, divided by the population. It reflects burden of disease and is influenced by both new cases and duration.

Ongoing, systematic collection, analysis, interpretation, and dissemination of health data used to plan, implement, and evaluate public health or infection prevention practice. Data must be acted upon to be meaningful.

A summary measure comparing the number of observed infections to the number predicted from national baseline data, adjusted for risk factors. A value above 1.0 indicates more infections than predicted.

The number of device days divided by the number of patient days for a given device such as a central line or urinary catheter. It helps interpret infection rates because device exposure drives risk.

A structured process of confirming an excess of cases, verifying the diagnosis, constructing a case definition, identifying and interviewing cases, generating hypotheses, and applying control measures. Steps may overlap and control should not wait for complete analysis.

A graph plotting the number of cases over time by date of onset. Its shape helps distinguish a point source, continuous common source, or propagated exposure and can suggest the incubation period.

The interval between exposure to an infectious agent and the appearance of the first symptoms or signs. It guides post-exposure monitoring periods and helps interpret epidemic curves.

The time during which an infected person can transmit the agent to others. It determines how long isolation or exclusion from work may be needed and differs from the incubation period.

A model describing the sequence needed for transmission: a pathogen, a reservoir, a portal of exit, a mode of transmission, a portal of entry, and a susceptible host. Breaking any link prevents infection.

The route by which an infectious agent moves from a source to a host, such as contact, droplet, airborne, vector-borne, or common vehicle. The route determines which precautions are required.

Infection control practices applied to every patient regardless of diagnosis, including hand hygiene, gloves, gowns, masks, eye protection as indicated, safe injection practice, and safe handling of contaminated equipment and linen.

Additional precautions beyond standard precautions used for patients with known or suspected pathogens spread by contact, droplet, or airborne routes. They specify room type, personal protective equipment, and visitor and transport rules.

Measures used for pathogens spread by direct or indirect contact, typically requiring gloves and gown for room entry, a private room or cohorting, and dedicated equipment. Examples include methicillin-resistant Staphylococcus aureus and Clostridioides difficile.

Measures for pathogens spread by large respiratory droplets generated during coughing, sneezing, or talking, requiring a mask for room entry and often a private room. Examples include influenza and pertussis.

Measures for pathogens carried on small particles that remain infectious over distance and time, requiring an airborne infection isolation room with negative pressure and respiratory protection such as an N95 respirator. Examples include tuberculosis and measles.

A single-patient room engineered with negative pressure relative to surrounding areas, directed airflow, and a defined number of air changes per hour to contain infectious aerosols. Exhaust air is typically filtered or discharged safely.

Cleaning hands with soap and water or an alcohol-based hand rub at the correct moments to remove or kill transient organisms. It is the single most effective routine measure for preventing healthcare-associated transmission.

Barriers such as gloves, gowns, masks, respirators, and eye protection worn to prevent exposure to infectious material. It must be donned and removed in a safe sequence with hand hygiene before and after.

Use of a fit-tested, seal-checked respirator such as an N95 filtering facepiece to reduce inhalation of infectious aerosols. It differs from a surgical mask, which mainly limits droplet emission and splash.

A formal procedure verifying that a specific respirator model and size forms an adequate seal on an individual wearer. It is required before use and repeated at defined intervals or after facial changes.

Grouping patients with the same confirmed or suspected pathogen in a shared area, or assigning staff to care only for such patients, to limit transmission. It is used when private rooms are limited during outbreaks.

Separating a patient with a known or suspected communicable infection from others to prevent spread. Precautions and duration are based on the pathogen and its mode of transmission.

An infection that a patient acquires during care in a healthcare setting and that was not present or incubating at admission. Surveillance definitions often use specific time windows and device criteria.

An infection occurring at or near an incision within a defined postoperative window, classified as superficial incisional, deep incisional, or organ space. Prevention relies on appropriate antimicrobial prophylaxis, glucose control, and asepsis.

A primary bloodstream infection in a patient with a central venous catheter in place during a defined window, not explained by another source. Prevention bundles emphasize insertion asepsis, site selection, and daily necessity review.

A urinary tract infection meeting surveillance criteria in a patient with an indwelling urinary catheter in place during a defined window. Limiting catheter use and duration is the main preventive strategy.

A surveillance definition for worsening respiratory status in a mechanically ventilated patient, including ventilator-associated pneumonia as a subcategory. It uses objective criteria such as oxygen and pressure changes rather than subjective interpretation.

A small set of evidence-based practices that, when performed together reliably, produce better outcomes than individual measures alone. Compliance is usually measured as all-or-none for the full set.

Practices that keep pathogens away from a site, including sterile technique for invasive procedures and clean technique for routine care. Aseptic technique protects both patients and staff.

Reducing skin flora before an invasive procedure using an appropriate antiseptic agent applied with friction and adequate contact time. It targets transient and resident organisms on the patient's skin and the hands of the procedural team.

A validated process that destroys all microbial life, including bacterial spores, on an item. Common methods include steam under pressure, ethylene oxide, hydrogen peroxide plasma, and dry heat.

A process that destroys all microorganisms except high numbers of bacterial spores, used for semi-critical items such as endoscopes. It requires cleaning first, correct concentration, temperature, and contact time.

A scheme categorizing medical items as critical, semi-critical, or noncritical based on the risk of infection if contaminated. The category determines whether sterilization, high-level disinfection, or low-level disinfection is required.

A prepared population of resistant microorganisms, usually bacterial spores, used to verify that a sterilization process achieved the required lethality. It is the most accepted means of routinely monitoring sterilizer efficacy.

A written program required for workplaces with exposure risk that describes engineering controls, work practice controls, personal protective equipment, hepatitis B vaccination, post-exposure evaluation, and training. It is reviewed and updated regularly.

Treatment given after a potential exposure to reduce the chance of infection, such as antiretroviral therapy after HIV exposure or vaccine and immunoglobulin after hepatitis B or measles exposure. It should begin as soon as possible after risk assessment.

The service and programs protecting healthcare personnel from work-related illness and injury, including immunization, exposure follow-up, respiratory protection, and return-to-work evaluation. It partners closely with infection prevention.

Measures that contain respiratory secretions, such as covering the mouth and nose, using tissues, performing hand hygiene, and offering masks to coughing patients. These reduce droplet and contact spread at the point of entry to care.

A structured, data-driven cycle of identifying a gap, testing changes, measuring results, and sustaining gains. Common frameworks include Plan-Do-Study-Act and root cause analysis for adverse events.

A systematic team method for finding underlying system failures that contributed to an adverse event, rather than blaming individuals. Findings should lead to redesign of processes and measurable follow-up.

The ability to appraise study design, bias, and evidence quality and to translate findings into practice and staff education. It supports choosing interventions that are effective rather than merely popular.

Skills for leading infection prevention programs, including policy development, committee reporting, regulatory compliance, conflict resolution, and clear communication during outbreaks. Effective programs require visible leadership support and feedback of data to frontline staff.

The physical and operational conditions of a healthcare facility, including construction and renovation barriers, water systems, ventilation, and surface cleanliness, that influence infection risk. Risk assessment during construction is a core activity.

Physical removal of soil and organic material from surfaces or items, usually with detergent and friction. It must precede disinfection or sterilization because soil reduces the effectiveness of antimicrobial agents.