AAMI PB70 is a four-level barrier classification: Level 1 (minimal risk, e.g., routine care), Level 2 (low risk, e.g., venipuncture), Level 3 (moderate risk, e.g., arterial blood draw), Level 4 (high risk, e.g., surgery with arterial fluid exposure). Higher levels resist more hydrostatic pressure and aerosol penetration.

Isolation gowns provide partial-back coverage for contact precautions and general patient care. Surgical gowns wrap fully around the back with reinforced critical zones for sterile procedures. Surgical gowns are sterile and meet Level 3–4; isolation gowns are typically non-sterile Level 1–3.

Chemo-rated gowns are tested for permeation resistance against hazardous drugs under ASTM F739 and D6978. They're required for compounding, administering, or disposing of chemotherapy and other hazardous drugs. Standard impervious gowns are not an adequate substitute.

Fluid-resistant SMS / SMMS gowns meet AAMI Level 1–3 and are appropriate for routine isolation and moderate fluid exposure. Impervious polyethylene or poly-coated gowns (typically Level 4) are required for high-risk fluid exposure, chemo, and arterial-pressure surgical work.

Disposable gowns are single-use and must be discarded after one patient encounter. Reusable polyester-blend gowns can be laundered and sterilized per facility reprocessing protocols, but require tracked reprocessing cycles and periodic barrier re-validation.