Surgical Insight’s

AAMI Levels

 The Association for the Advancement of Medical Instrumentation

Navigating AAMI Levels for Optimal Safety in Surgery

In the critical zones of gowns and drapes, where operating room teams come into direct contact with blood and bodily fluids, the “AAMI Standard” (ANSI/AAMI PB70:2012) establishes guidelines for liquid barrier performance.

Level 1: Basic Fluid Protection

  • It is ideal for non-surgical situations in hospitals or clinics, such as primary patient care, examinations, and minor non-invasive operations.
  • Typical Application: Handling simple patient care activities with little danger of fluid exposure. This includes changing bed linens, washing patients, and managing essential wound care in a non-surgical setting. It is not suggested for any surgical procedures in the operating room.

Level 2: Low Fluid Protection

  • Suitable for Minimally invasive surgeries and minor procedures with less danger of fluid splash or exposure.


  1. Dermatological procedures include the removal of skin lesions, minor excisions, and biopsies.
  2. Orthopedic operations include simple arthroscopy, modest closed fracture reductions, and casting for damaged bones.
  3. Ophthalmic surgeries include cataract surgery, pterygium excision, and other minor eye procedures.

Level 3: Moderate Fluid Protection

  • Appropriate for A wider variety of surgical procedures with moderate fluid exposure risk. Level 3 gowns are more fluid-resistant and ideal for a wide range of general operations.


  1. General surgery includes appendectomies, cholecystectomies, and hernia repairs.
  2. Obstetrics and Gynecology: Cesarean section, hysterectomy, and other gynecological procedures.
  3. Orthopedics: Most open fracture reductions, some joint replacements (depending on anticipated fluid exposure), and more sophisticated arthroscopic procedures.

Level 4: Maximum Fluid and Microbial Protection

  • Protects the most crucial surgeries with long durations, extensive fluid exposure, or a high risk of infection.


  1. Cardiothoracic surgery includes open-heart surgeries, lung resections, and other procedures that require extensive fluid exposure.
  2. Trauma and Emergency procedure: Procedures involving severe trauma, extensive blood loss, or when the length and complexity of the procedure raise the danger of fluid exposure.
  3. Severe orthopedic surgery includes complex joint replacements, spinal fusions, and severe fracture operations that provide a high risk of blood and fluid exposure.

Special Considerations

Use of Bone Cement: Used in operations such as joint replacements, bone cement generates heat and necessitates higher AAMI level gowns.

Use of Power Tools: Power tools are frequently used in orthopedic surgery, which can produce aerosols and spatter, necessitating higher AAMI level gowns.


ASTM F1671 / F1671M-13, Standard Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne Pathogens Using Phi-X174 Bacteriophage Penetration as a Test System, ASTM International, West Conshohocken, PA, 2013, <>

AAMI (2023, January). ANSI/AAMI PB70:2022, Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities.

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