Universal precautions were introduced by the Centers for Disease Control (CDC) in 1985, mostly in response to the human immunodeficiency virus (HIV) epidemic. [1][2][3]Universal precautions are a standard set of guidelines aimed at preventing the transmission of bloodborne pathogens from exposure to blood and other potentially infectious materials (OPIM). OPIM is defined by the Occupational Safety and Health Administration (OSHA) as:

• The following human body fluids: semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, pericardial fluid, peritoneal fluid, amniotic fluid, saliva in dental procedures, any body fluid that is visibly contaminated with blood, and all body fluids in situations where it is difficult or impossible to differentiate between body fluids;
• Any unfixed tissue or organ (other than intact skin) from a human (living or dead); and
• HIV-containing cell or tissue cultures, organ cultures, and HIV- or HBV-containing culture medium or other solutions; and blood, organs, or other tissues from experimental animals infected with HIV or HBV.

Universal precautions do not apply to sputum, feces, sweat, vomit, tears, urine, or nasal secretions unless they are visibly contaminated with blood because their transmission of Hepatitis B or HIV is extremely low or non-existent.

In 1987, the CDC introduced another set of guidelines termed Body Substance Isolation. These guidelines advocated the avoidance of direct physical contact with “all moist and potentially infectious body substances,” even if blood is not visible. A limitation of this guideline was that it emphasized handwashing after removal of gloves only if the hands were visibly soiled.

In 1996, the CDC Guideline for Isolation Precautions in Hospitals, prepared by the Healthcare Infection Control Practices Advisory Committee (HICPAC), combined the major features for Universal Precaution and Body Substance Isolation into what is now referred to as Standard Precautions. These guidelines also introduced three transmission-based precautions: airborne, droplet, and contact. All transmission-based precautions are to be used in conjunction with standard precautions.[4][5][6]

Standard Precautions

Standard precautions apply to the care of all patients, irrespective of their disease state. These precautions apply when there is a risk of potential exposure to (1) blood; (2) all body fluids, secretions, and excretions, except sweat, regardless of whether or not they contain visible blood; (3) non-intact skin, and (4) mucous membranes. This includes the use of hand hygiene and personal protective equipment (PPE), with hand hygiene being the single most important means to prevent transmission of disease.[7][8][9][10]

Personal protective equipment is used as a barrier to protect skin, mucous membranes, airway, and clothing, and includes gowns, gloves, masks, and face shields or goggles.

The following list of standard precautions is not all-inclusive, and contains some of the most commonly used recommendations for healthcare workers.

Hand Hygiene

Hand washing with soap and water for at least 40 to 60 seconds, making sure not to use clean hands to turn off the faucet, must be performed if hands are visibly soiled, after using the restroom, or if potential exposure to spore-forming organisms.

Hand rubbing with alcohol applied generously to cover hands completely should be performed and hands rubbed until dry.

Hand Hygiene Indications

• Before and after any direct patient contact and between patients, whether or not gloves are worn.
• Immediately after gloves are removed.
• Before handling an invasive device.
• After touching blood, body fluids, secretions, excretions, non-intact skin, and contaminated items, even if gloves are worn.
• During patient care, when moving from a contaminated to a clean body site of the patient.
• After contact with inanimate objects in the immediate vicinity of the patient.

Gloves

Must be worn when touching blood, body fluids, secretions, excretions, mucous membranes, or non-intact skin. Change when there is contact with potentially infected material in the same patient to avoid cross-contamination. Remove before touching surfaces and clean items. Wearing gloves does not mitigate the need for proper hand hygiene.

Mask, Goggles/Eye Visor, and/or Face Shield

Wear a mask and eye protection or face shield during procedures that may spray or splash blood, body fluids, secretions, or excretions.

Gown

Wear to protect skin or clothing during procedures that may spray or splash blood, body fluids, secretions, or excretions.

Needles and Other Sharps

Do not break, bow, or directly manipulate used needles. Recapping is not recommended, but if necessary, “use a one-handed scoop technique only.” Discard all used sharps in appropriate puncture-resistant containers.

Transmission-based Precautions

Airborne Precautions

These precautions are used in patients with known or suspected infection with pathogens that are spread by airborne transmission, i.e., “airborne droplet nuclei (small-particle residue {5 um or smaller in size} of evaporated droplets that may remain suspended in the air for long periods of time) or dust particles containing the infectious agent.”

Patient Placement

Patients should be placed in a negative pressure isolation room that allows a minimum of 6 to 12 air changes per hour. Patients with the active infection with the same pathogen, and no other infection, may be roomed together (cohorting). Doors to the room must remain closed at all times. “When a private room is not available, and cohorting is not desirable, consultation with infection control professionals is advised before patient placement.”

PPE

Respirators that filter at least 95% of airborne particles must be worn over the nose and mouth, i.e., N95 respirator or powered air-purifying respirator (PAPR) with a high-efficiency particular air (HEPA) filter.

Transport

When necessary, patients being transported out of their rooms should wear a surgical mask.

Droplet Precautions

These precautions are used in patients with known or suspected infection with pathogens that are spread by droplet transmission. “Droplets are particles of respiratory secretions +/- 5 microns. Droplets remain suspended in the air for limited periods. Transmission is associated with exposure within three to six feet (one to two meters) of the source.”

Patient Placement

Private rooms are preferred; however, they may be placed in a semi-private room with another patient having the same active infection, and no other infection (cohorting). When a private room or cohorting is not available, the infected patient should be placed at least 3 feet away from other patients and visitors. The doors to the room may be left open, and no special air handling is required 

PPE

Surgical masks should be worn while within 6 feet of the patient.

Transport

When necessary, patients being transported out of their rooms should wear a surgical mask.

Contact Precautions

These precautions are used in patients with known or suspected infection or colonization with pathogens that are spread by direct and indirect patient contact. Indirect patient contact occurs when physical contact is made with items or surfaces in the patient’s environment.

Patient Placement

Private rooms are preferred; however, they may be placed in a semi-private room with another patient having the same active infection, and no other infection (cohorting). “When a private room is not available, and cohorting is not achievable, consider the epidemiology of the microorganism and the patient population when determining patient placement. Consultation with infection control professionals is advised before patient placement.”

PPE

Gloves and gowns should be donned prior to entering the patient's room, and removed before leaving. Hand hygiene should be performed immediately afterward. Care should be taken not to touch any potentially contaminated surface upon leaving the room.[11][12]

Transport

Maintain contact precautions at all times.

Patient Equipment

When possible, patients should have dedicated equipment that remains in the room with them, e.g., single-patient-use blood pressure cuff. If single-patient-use items are not available, then they should be cleaned and disinfected before use on another patient.

Airborne precautions should be used for the following infections and conditions for the minimum duration listed:

• Aspergillosis if “massive soft tissue infection with copious drainage and repeated irrigations required.”
• Herpes Zoster that is disseminated or in immunocompromised patients (duration of illness).
• Measles (duration of 4 days after onset of rash in immunocompotent host; duration of illness in immunocompromised).
• Monkeypox (duration is until diagnosis is confirmed and smallpox has been excluded).
• Severe acute respiratory syndrome (duration of illness plus 10 days after fever and respiratory symptoms have resolved or improved).
• Smallpox (duration of illness).
• Tuberculosis: pulmonary or laryngeal (duration until improving clinically on effective therapy with three negative sputum smears on consecutive days).
• Tuberculosis: extrapulmonary, draining lesions (duration until clinically improving and drainage has stopped or there are consecutively three negative cultures).
• Varicella Zoster (duration until the lesions crust and dry).

Droplet precautions should be used for the following infections and conditions for the duration listed:[13]

• Adenovirus: pneumonia (duration of illness).
• Diphtheria: pharyngeal (duration is until completion and antibiotics and 2 negative cultures 24 hours apart).
• Haemophilus influenzae type b: epiglottitis or meningitis (duration is until 24 hours after initiating effective therapy).
• Influenza, pandemic
• Neisseria meningitidis: meningitis, sepsis, or pneumonia (duration is until 24 hours after initiating effective therapy).
• Mumps (duration is 5 days after onset).
• Mycoplasma pneumonia (duration of illness).
• Parvovirus B19 (duration is 7 days in acute disease, duration of hospitalization in chronic disease of immunocompromised host).
• Pertussis (duration is 5 days).
• Yersinia pestis: pneumonic plague (duration is 48 hours).
• Group A Streptococcus: pneumonia, pharyngitis, scarlet fever, serious invasive disease (duration is until 24 hours after initiating effective therapy).
• Rhinovirus (duration of illness).
• Rubella (duration is until 7 days after rash onset).
• Severe acute respiratory syndrome (duration of illness plus 10 days after fever and respiratory symptoms have resolved or improved).
• Ebola, Marburg, Crimean-Congo, and Lassa fever viruses: viral hemorrhagic fevers (duration of illness).

Contact precautions should be used for the following infections and conditions for the duration listed:

• Abscess, major draining (duration of illness, until cessation of drainage).
• Adenovirus: pneumonia (duration of illness).
• Burkholderia cepacia in Cystic Fibrosis patients.
• Bronchiolitis (duration of illness).
• Clostridium difficile (duration of illness).
• Congenital rubella (duration is until 1 year of age, or urine and nasopharyngeal cultures consistently negative after 3 months of age).
• Conjunctivitis, viral (duration of illness).
• Diphtheria: cutaneous (duration is until completion and antibiotics and 2 negative cultures 24 hours apart).
• Staphylococcal furunculosis (duration of illness).
• Rotatvirus (duration of illness).
• Hepatitis A (duration is age specific in incontinent patients: children < 3 years old is duration of hospitalization; 3-14 years old is 2 weeks after onset; > 14 years old is 1 week after onset).
• Herpes simplex: neonatal, disseminated, severe, or mucocutaneous (duration is until lesions dry and crust).
• Herpes zoster: disseminated (duration of illness).
• Human metapneumovirus (duration of illness).
• Impetigo (duration is until 24 hours after initiating effective therapy).
• Lice: head (duration is until 24 hours after initiating effective therapy).
• Monkeypox (duration is until lesions crust).
• Multidrug-resistant organisms infection or colonization (duration is while evidence of ongoing or increased risk of transmission, or while there are wounds that cannot be covered).
• Parainfluenza virus (duration of illness).
• Poliomyelitis (duration of illness).
• Pressure ulcer, major infected (duration of illness).
• Respiratory syncytial virus: infants, young children, and immunocompromised adults (duration of illness).
• Staphylococcal scalded skin syndrome, Ritter’s disease (duration of illness).
• Scabies.
• Severe acute respiratory syndrome (duration of illness plus 10 days after fever and respiratory symptoms have resolved or improved).
• Smallpox (duration of illness).
• Staphylococcus aureus skin infection, major (duration of illness).
• Group A streptococcus skin infection, major (duration is until 24 hours after initiating effective therapy).
• Tuberculosis: extrapulmonary, draining lesions (duration is until clinically improving and drainage has stopped or there are consecutively three negative cultures).
• Vaccinia (duration is until lesions crust and dry).
• Varicella zoster (duration is until lesions crust and dry).
• Ebola, Marburg, Crimean-Congo, and Lassa fever viruses: viral hemorrhagic fevers (duration of illness).
• Wound infections, major (duration of illness).

Occupational exposure to blood and other potentially infectious materials (OPIM) is of such great concern that multiple government agencies have instituted guidelines and regulations regarding universal precautions. Knowledge and implementation of standard precautions are vital to limiting the spread of infectious disease.[14][15] Their use requires the healthcare provider to be proactive in anticipating the types of exposure they may encounter with each patient, e.g., a trauma patient with arterial bleeding would require donning gloves, mask with face shield, and gown. In regards to transmission-based precautions, the healthcare provider should be aware that some diseases require more than one type of transmission-based precautions, e.g., disseminated herpes zoster requires contact, airborne, and standard precautions.

Proper Donning and Removal of PPE

Donning of PPE

The CDC recommends that PPE be donned in following sequence: (1) gown, (2) mask or respirator, (3) goggles or face shield, and (4) gloves.

Removal of PPE

The safe removal of PPE also follows a specific sequence that requires special attention to areas that are now considered contaminated: (1) gloves should be removed by first grasping the palm of the other hand and peeling off the first glove, keep hold of the removed glove in the gloved hand, slide the fingers of the ungloved hand under the remaining glove and peel it off over the first glove, (2) goggles or face shield should be removed by lifting from behind the head, (3) gowns should untied and removed by pulling away from the neck and shoulders, turning the gown inside out and only touching the inside, (4) mask or respirator should be removed by reaching behind the head and grasping the bottom ties then the top ties, and removing without touching the front. Alternatively, the gloves and gown may be removed at the same time by grasping the gown from the front and pulling away from the body, rolling the gown into a bundle, and removing the gloves at the same time using the inside of the gown. Hand hygiene should be performed after removal of all PPE, and anytime during removal if they become contaminated.