AAMI PB70 barrier levels: what each number means
AAMI PB70 grades surgical gowns into four levels of fluid resistance, and the level is the single most important number on a gown specification. Level 1 resists light fluid and is meant for minimal-risk contact. Level 2 resists splash and light spray, which covers most routine care. Level 3 resists heavier fluid exposure and is the common choice for surgery and high-fluid procedures. Level 4 resists viral penetration under pressure and is reserved for the highest-risk, high-fluid surgical work. The level is not a quality score β it is a match to the procedure, so a Level 1 gown is not 'worse' than a Level 4 gown, it is simply specified for a lower-risk task.
- Level 1: minimal fluid risk, light contact
- Level 2: splash and light spray, routine care
- Level 3: heavier fluid exposure, surgery
- Level 4: viral penetration resistance under pressure



