How to Evaluate and Select Isolation Gowns

Isolation gowns are among the most frequently used types of personal protective equipment in healthcare environments. Their primary purpose is to protect the wearer from exposure to infectious diseases when coming in contact with body fluids.

However, not all isolation gowns are created equal. Distinguishing the different properties, protection levels, and intended purposes is critical to maintaining a proper infection control strategy.

General Information

Isolation gowns have several alternative names such as medical gown, procedural gown, and nursing gown, all of which refer to a gown-like medical garment made of synthetic materials. These gowns are mainly designed to shield the wearer against exposure to bodily fluids and solids that can potentially transmit pathogens.

All types of isolation gowns generally protect only the front of the body, including the arms and most of the legs, leaving the back exposed. Gowns differ from isolation coveralls, which provide front and back coverage for high-risk contamination areas.

Isolation Gowns

Protective Capabilities

The FDA recognizes the protection levels introduced by ANSI/AAMI PB70, a consensus standard jointly created by the American National Standards Institute (ANSI) and the Association for the Advancement of Medical Instrumentation (AAMI).

According to the standards outlined under ANSI/AAMI PB70, there are four levels of protection for isolation gowns, ranked by risk level:

  • Level 1 (Minimal protection)
  • Level 2 (Low protection)
  • Level 3 (Moderate protection)
  • Level 4 (High protection)

Only Levels 3 and 4 are considered suitable for use as surgical gowns. Levels 1 and 2 are only appropriate as non-surgical isolation gowns for low-risk situations.

Level 1 isolation gowns

A Level 1 isolation gown provides the lowest level of protection against fluid penetration. This protection level is suitable for minimal-risk, general healthcare applications, such as basic care, standard medical units, nursing home care, or medical facility visitors.

A level 1 gown is often made of lightweight chlorinated polyethylene (CPE), a synthetic material similar to polyethylene. Although thin, Level 1 CPE gowns offer protection against water, blood, and microbial exposure in low-risk environments.

Like other personal protective equipment, level 1 gowns are disposable and should not be washed or reused.

AAMI Level 1 performance requirements (4% AQL):

  • Water spray impact penetration: equal or less than 4.5 grams

Level 2 isolation gowns

Level 2 gowns employ heavier synthetic fabrics, providing additional pathogen resistance and making them suitable for low-risk healthcare applications, such as suturing, pathology labs, blood drawing, or intensive care unit (ICU) work.

Like their Level 1 counterparts, most Level 2 isolation gowns are disposable and available in multiple plastic materials, such as CPE, polypropylene (PP), or polyethylene (PE).

A gown advertised as SMS fabric is made of polypropylene fabricated using the spun-bond/melt-blown/spun-bond (SMS) process, similar to the fabric used in face masks. SMS fabric is breathable yet provides adequate protection against fluid projections.

AAMI Level 2 performance requirements (4% AQL):

  • Water spray impact penetration: equal or less than 1 gram
  • Hydrostatic pressure resistance: equal or less than 20 cm

Level 3 surgical gowns

Level 3 gowns are the lowest protection level considered suitable for surgical applications, offering a high level of protection against the transfer of microorganisms.

Level 3 gowns are ideal for use in the emergency room (ER) and other critical care units such as trauma and burn. They are also suitable for arterial blood drawing, intravenous insertions, and other operations with a moderate risk of heavy blood splatters.

Level 3 surgical gowns may be disposable or reusable, although the latter types are only reusable to a certain extent.

Disposable Level 3 gowns use similar materials to their Level 1 and 2 counterparts but are constructed with a higher material density to provide a higher protection level. This makes them heavier to wear.

Reusable isolation gowns do not employ plastics like CPE, PP, or PE in their construction, instead featuring machine-washable cotton or polymer fibers, for example, polyester or poly-cotton.

However, a gown’s reusability is not unlimited. Each gown has a maximum wash cycle limit; in other words, you can only wash it up to a certain number of times. Once that number has been reached, further wash cycles may degrade the gown’s impermeability, no longer guaranteeing Level 3 protection.

AAMI Level 3 performance requirements (4% AQL):

  • Water spray impact penetration: equal or less than 1 gram
  • Hydrostatic pressure resistance: equal or less than 50 cm

Level 4 surgical gowns

Level 4 is the highest protection rating available for surgical gowns. They provide adequate protection against bloodborne pathogens in high-risk operations where blood spraying is highly likely or impossible to avoid, such as surgery.

AAMI standards require level 4 isolation gowns to undergo a barrier test with simulated, virus-contaminated blood. A surgical gown is eligible for Level 4 specification if it can prevent all fluid and virus penetration for a minimum duration of one hour.

Health care personnel rarely need Level 4 gowns; they are typically reserved for surgeons and their assistants. Like their Level 3 equivalents, disposable and reusable gowns are available, and the reusable models have a maximum wash cycle limit.

AAMI Level 4 performance requirements (4% AQL):

  • Surrogate blood spray impact penetration: no penetration at 2 psi for at least one hour
  • Viral penetration test (Bacteriophage Phi-X174): no penetration at 2 psi for at least one hour

Additional Properties

Although protection level is a critical element of an isolation gown, there are other properties you may need to look for, depending on the intended applications.

Clean vs. sterile

A clean isolation gown may be free of dirt, grime, stains, and other visible forms of soiling, but it may still contain trace amounts of microorganisms. A clean gown is suitable for general use and protection from pathogens. However, it may not be sufficient for health care personnel operating in high-risk environments like the surgery room because they risk contaminating their patients.

A sterile isolation gown is not just free of stains but also sterilized of all bacteria, viruses, and other potentially pathogen-carrying microorganisms capable of reproducing and spreading. Sterile gowns are a requirement for surgery, intensive care, or any other environment requiring a high level of infection control.

Ease of use

It is critical to select a gown model that is easy to put on and remove, as improper donning and doffing can put staff at a higher risk of contamination. A gown model that is difficult to take off by yourself may be frustrating to remove and expose you to any pathogens sprayed on the gown’s surface.


Ideally, your facility should have access to an adequate number of gowns in as many protection levels and sizes as needed by your staff members.

Gown sizes too large for your personnel may limit their freedom of movement and hinder their ability to perform tasks. However, sizes too small may not provide enough coverage, exposing them to infection.

Protect Yourself Against Pathogens With ICU Production, Inc.

Although all isolation gowns are essential PPE, distinguishing between each type’s protection level and properties is vital to assign the correct gowns to the right personnel.

ICU Productions, Inc. is a leading provider of premium-quality personal protective equipment, approved by the FDA and the CDC. Browse our large selection of PPE, including isolation and surgical gowns (levels 1 to 4), coveralls, face masks, face shields, nitrile gloves, hand sanitizer, and child-safe PPE.