KOSA Kosa-med · Product Guidance
ASTM Level 1-4 Surgical Gown Selection Guide
Surgical and isolation gowns are rated AAMI/ANSI/AAMI PB70 (ASTM F2407) Levels 1-4 by liquid-barrier performance. Match the level to the procedure's fluid exposure: Level 1 for low risk, Level 4 for high-fluid and infectious-risk care.
Key Takeaways
- AAMI PB70 (ASTM F2407) defines Levels 1-4 by liquid-barrier performance, not fabric weight.
- Level 1 is for minimal-risk care; Level 4 adds a full viral barrier for high-fluid procedures.
- Higher levels require more barrier material — SMS, PE/PP film and reinforced zones.
- Match the level to expected fluid exposure, not to price.
- Follow your facility's infection-control protocol and the product's stated level.
What the AAMI levels mean
Under AAMI/ANSI/AAMI PB70 (referenced by ASTM F2407), surgical and isolation gowns are classified Level 1 to Level 4 by how well they resist liquid penetration. The level predicts protection in the operating room, ER and isolation care.
| Level | Typical use case | Barrier |
|---|---|---|
| Level 1 | Basic care, standard isolation, visitor/cover gowns | Minimal risk, low fluid |
| Level 2 | Blood draw, suturing, ICU, low-risk outpatient | Low risk, small fluid amount |
| Level 3 | Arterial blood draw, ER, trauma, moderate-fluid procedures | Moderate risk, larger fluid |
| Level 4 | Long, high-fluid surgery, infectious-risk care | High risk + viral barrier |
Material implications by level
Barrier rises with level. Level 1-2 often use light SMS or spunlace; Level 3 favours heavier SMS; Level 4 adds a PE/PP film or reinforced frontal zone for a sealed fluid and viral barrier.
- Level 1-2: breathable SMS or PP — comfort for low-risk, short tasks.
- Level 3: heavier SMS, sometimes film-backed chest panel.
- Level 4: full film or reinforced barrier with sealed seams to block fluid and pathogen penetration.
Selection checklist
1. What is the expected fluid exposure?
Minimal/low → Level 1-2; moderate → Level 3; high-fluid or infectious → Level 4.
2. How long is the procedure?
Extended wear favours breathable SMS where the level allows it.
3. Is a viral barrier required?
Only Level 4 provides a tested viral barrier — specify it for high-risk care.
4. Does the facility protocol mandate a level?
Follow the stated level and change frequency before comfort trade-offs.
Level guidance above is general. Always follow your facility's infection-control protocol and the product's stated AAMI PB70 level and test method.
Need a specification for your line?
Send your fluid, flow and hygiene class — we return a documented recommendation.
Contact KOSA Kosa-medFrequently asked questions
What do AAMI PB70 Levels 1-4 measure?
They classify gowns by liquid-barrier performance under standardized impact and hydrostatic-pressure tests, referenced by ASTM F2407. The level predicts how well the gown resists fluid penetration during care, independent of its fabric weight.
When should a Level 4 gown be used?
Level 4 is specified for high-fluid procedures and infectious-risk care where a full viral barrier is required — for example long surgeries with heavy irrigation or known contagious exposure. Lower levels do not provide that barrier.
Does a higher fabric weight mean a higher level?
No. The AAMI level is set by tested barrier performance and seam construction, not fabric weight alone. A light gown can rate Level 3, while a heavy one without a tested barrier may not.
How do I choose the right level in practice?
Match the level to expected fluid exposure: Level 1 for minimal-risk basic care, Level 2-3 for procedural and ER use, Level 4 for high-fluid or infectious-risk care, and confirm against your facility's protocol and the product's stated level.