Look for an AAMI barrier level on a surgical gown's label. Level 3 and Level 4 are the two highest levels, and the gap between them matters more than it looks. This guide explains what each level is tested for, where each one is typically used, and what to check before you order a case. As examples it uses our two FDA 510(k) cleared gowns: the Bodygard SFS Surgical Gown Level 3 and the Bodygard SFS Surgical Gown Level 4.
What AAMI PB70 measures
ANSI/AAMI PB70, "Liquid barrier performance and classification of protective apparel and drapes intended for use in health care facilities", is the consensus standard FDA recognizes for rating gowns. It sorts protective apparel into four levels by how well the material stops liquid, and in the case of Level 4, liquid-borne pathogens. Level 1 is the lowest and Level 4 is the highest.
Two points are easy to miss:
- The level only measures liquid barrier. It does not measure strength, comfort or breathability, which are tested separately (tensile, tear and seam strength, lint, water-vapor transmission).
- The level applies to the critical zones. For a surgical gown, the critical zones are the front of the body from the top of the shoulders to the knees, and the arms from the cuff to above the elbow. The back of a surgical gown may be non-protective. If a gown says "Level 4", it is the critical zones that met Level 4.
The tests behind each level
| AAMI PB70 level | Test(s) | Pass criterion | Expected barrier |
|---|---|---|---|
| Level 1 | AATCC 42 water impact | <= 4.5 g | Minimal water resistance (some resistance to spray) |
| Level 2 | AATCC 42 water impact AATCC 127 hydrostatic pressure | <= 1.0 g >= 20 cm | Low water resistance |
| Level 3 | AATCC 42 water impact AATCC 127 hydrostatic pressure | <= 1.0 g >= 50 cm | Moderate water resistance (spray plus some resistance to soaking under pressure) |
| Level 4 | ASTM F1671 viral penetration (gowns) ASTM F1670 synthetic blood (drapes) | No penetration at 2 psi (13.8 kPa) | Blood and viral penetration resistance |
The step from Level 3 to Level 4 is the biggest in the scale. Levels 1 to 3 use water tests and differ in how hard the water is pushed. Level 4 changes the challenge itself. The material is exposed to simulated blood containing the bacteriophage Phi-X174, a virus surrogate, at 2 psi. If no virus comes through by the end of the test, the material passes.
Level 3 vs Level 4 at a glance
| Level 3 | Level 4 | |
|---|---|---|
| Risk level (AAMI) | Moderate | High |
| Key tests | AATCC 42 <= 1.0 g and AATCC 127 >= 50 cm | ASTM F1671, no viral penetration at 2 psi |
| Typical situations | Arterial blood draw, inserting an IV line, emergency room, trauma | Long, fluid-intense procedures and surgery; when pathogen resistance is needed or non-airborne infectious disease is suspected |
| Bodygard model | Bodygard SFS Surgical Gown Level 3 | Bodygard SFS Surgical Gown Level 4 |
| FDA 510(k) | K202845 | K221139 |
These examples come from the AAMI risk descriptions. They are not a rule. Which level a procedure needs is up to your facility's infection prevention team, who know the expected fluid volume, the procedure length and the patient population.
When Level 3 is enough, and when to step up
Our Level 3 gown is described as suitable for most procedures. It handles splash and a fair amount of fluid pressure on the chest and sleeves. Consider Level 4 when:
- the procedure is long and you expect heavy fluid exposure in the critical zones (for example, the forearms resting in a wet field);
- the team leans on the sterile field or has prolonged contact with soaked drapes;
- blood-borne pathogen exposure is a specific concern and your protocols ask for viral-penetration-tested apparel.
Level 4 testing is done on top of the Level 1-3 tests, so a Level 4 gown also meets the lower levels. The reverse is not true. If you stock both and assign them by procedure type, the higher-cost gown goes only where it is needed.
What both Bodygard SFS gowns have in common
The two Bodygard gowns are built on the same platform. According to their FDA 510(k) summaries, both are:
| Feature | Bodygard SFS Level 3 and Level 4 |
|---|---|
| Fabric | SFS: SMS nonwoven / film / SMS nonwoven |
| Style | Poly-reinforced |
| Basis weight | 60 g/m2 |
| Construction | Ultrasonic bonding |
| Sizes | M, L, XL, XXL |
| Sterilization | Ethylene oxide, SAL 10^-6 |
| Strength | Breaking > 30 N, tear > 20 N, seam > 50 N |
| Linting / flammability | ISO 9073-10 below log10 4; 16 CFR 1610 Class I |
| Biocompatibility | Non-cytotoxic, non-irritating, non-sensitizing (ISO 10993) |
The difference is barrier performance. The Level 4 gown passed ASTM F1671 with no detectable Phi-X174 transfer. Both gowns passed ASTM F1670 synthetic blood at 2 psi. The Level 4 summary also lists knit cuffs and a hook-and-loop closure. Full data is in the spec tables on each product page and in the surgical gowns overview.
Reading the label: three common mix-ups
"Reinforced" does not automatically mean Level 4. Gowns can be fabric-reinforced or poly-reinforced, and both kinds come in different levels. Read the AAMI level printed on the label, not the style name.
Product names are not standardized. "Isolation gown", "procedure gown", "cover gown" and "surgical gown" are used loosely. Look for labeling that states the intended use and the AAMI level.
Surgical gowns and surgical isolation gowns have different critical zones. A surgical gown protects the front and the sleeves. On a surgical isolation gown, everything except the bindings, cuffs and hems is a critical zone. Both are Class II devices that need a 510(k). Bodygard SFS gowns are cleared as surgical gowns (product code FYA).
Buying checklist for Level 3 and Level 4 gowns
Before you order in volume, check:
- AAMI level on the label, and that it matches what your protocol asks for.
- FDA 510(k) number. Look it up in the FDA database and make sure the trade name matches the product. Our guide What FDA 510(k) Clearance Means for Surgical Masks and Gowns shows how.
- Sterility. Method and SAL (Bodygard: EO, SAL 10^-6).
- Size mix. Bodygard SFS gowns come in M to XXL.
- Samples. Test the fit and glove-cuff interface with your own team before you switch.
Get a quote or samples
Bodyguard Advanced Materials LLC supplies Bodygard SFS Level 3 and Level 4 surgical gowns to US hospitals, surgery centers and distributors from Miami, FL. Request pricing or samples on the Level 3 or Level 4 product page, email sales@bodyguardus.com or call +1 (201) 881-2055. For more on Level 3, see What Is an AAMI Level 3 Surgical Gown?.
22 October 2026
