PPE CASE

Personal Protective Equipment Conformity Assessment Studies and Evaluations

Performance of Stockpiled Level 3 Surgical Gowns Sampled from 

Six Stockpile Facilities 

National Institute for Occupational Safety and Health (NIOSH)

National Personal Protective Technology Laboratory (NPPTL)

Lee A. Greenawald, Susan M. Moore, Selcen Kilinc-Balci, Patrick L. Yorio

October 19th, 2022 

This report details the results for spray impact and hydrostatic 

resistance performance for 1,040 Level 3 surgical gowns collected 

from six U.S. stockpile facilities, including one federal stockpile and 

five state stockpiles. Performance for stockpiled air-purifying 

respirators sampled from these same stockpile facilities can be found 

on NIOSH’s PPE CASE Reports website.

In the event of a national emergency, eighteen million U.S. healthcare 

workers may face high-consequence infectious disease exposures 

[NIOSH 2017a]. The use of personal protective equipment (PPE), such 

as gowns, gloves, goggles, and respirators, is an important measure within the infection prevention hierarchy of 

controls. Recent outbreaks—even those that occurred without extensive impact on US operations (e.g., 2009 

H1N1 pandemic, 2016 Ebola outbreak)—caused respirator shortages; when the first US fatality was reported 

during the Ebola outbreak, the PPE orders increased 10-200 fold [CDC 2021; DHHS 2012; NIOSH 2018]. To 

prepare for these surge demands, emergency planners stockpile large quantities of PPE at federal and state 

levels to support local supplies [Patel et al. 2017]. 

Due to the decision to stockpile PPE, stockpile personnel and decision makers have sought to explore the 

effectiveness of PPE after long-term storage (e.g., over five years). Use of gowns or other types of PPE past their 

designated shelf life is not recommended but has been observed in the US where there are surges in demand 

and the use of PPE past its shelf life is needed. Over the past decade the Strategic National Stockpile (SNS) and 

state and local stockpile personnel asked NIOSH to evaluate the performance of stockpiled PPE as well as to 

better understand storage conditions in U.S. stockpile facilities that store PPE; however, until recently this 

testing did not include respirators and was performed on only a small number of samples for face shields and 

gowns [NIOSH 2017b; NIOSH 2018]. 

In 2017, NIOSH established a PPE Stockpile Partnership consisting of 1) federal agencies and the SNS; 2) state, 

county, and city stockpiles; 3) hospital-related stockpile entities; and 4) a manufacturer trade association to 

inform the design and execution of an empirical study to evaluate stockpiled air-purifying respirators (APR) and 

End user protections will be 

enhanced by revisions to 

AAMI PB70 to define 

minimum critical zone 

boundaries and include 

guidance for post-market 

quality assurance sampling 

and data interpretation for 

third party entities.
2

surgical gowns from ten US stockpile facilities, where this study was conducted in accordance with the study 

design outlined in Greenawald et al. 2021. The APR performance results can be found on NIOSH’s PPE CASE 

Reports website. This report summarizes the performance testing results of two stockpiled Level 3 surgical 

gowns models including Medline Proxima Aurora and Cardinal Health Astound. A total of 1,040 Level 3 surgical 

gowns were sampled from six facilities. Being one level out of four (Level 1 being the least protective to Level 4 

being the most protective), Level 3 surgical gowns are worn by healthcare personnel during surgical procedures 

to protect both the patient and healthcare personnel from the transfer of microorganisms, body fluids, and 

particulate matter [FDA 2021]. 

How NIOSH Evaluated Surgical Gowns and Storage Conditions

Description of the Six Facilities

• From 2017 to 2019, NIOSH researchers visited six stockpile facilities, geographically dispersed across the 

US. These facilities included one federal stockpile and five state stockpiles. These facilities were in the 

Department of Health and Human Services (HHS) Regions 1, 2, 6, 9, and 10, and are shown in Figure 1. 

These facilities were selected based on their inventories and availability of Level 3 surgical gowns, disparate 

storage conditions, and type of facility. This methodology is further described in Greenawald et. al 2021.

Figure 1. Locations of the six collaborating stockpile facilities by HHS national regions. 

Assessment of Storage Conditions

• NIOSH, in conjunction with the PPE Partnership members, developed checklists to document site and 

packaging (i.e., pallet and case) conditions that may impact surgical gown performance. Example 

checklists can be found in Greenawald et al 2021. 

• NIOSH documented site storage conditions, including the presence of: 1) dust, moisture, fans, windows, 

doors, and ventilations systems; and 2) chemicals such as cleaning products, vermin traps, and pesticide 

treatment schedules—no indication of PPE product exposure was identified.
3

• NIOSH documented PPE pallet-specific storage conditions including: 1) the presence of dust, shrinkwrapping around the pallet, and moisture on the exterior packaging; 2) exposure to sunlight and direct 

light; 3) proximity to fans, windows, doors, and ventilation systems; 4) damage to shrink wrapping; and 

5) location of pallet on storage rack (e.g., top, bottom).

• NIOSH documented PPE case-specific storage conditions including: 1) the presence of dust and 

moisture; 2) exposure to sunlight and direct light; 3) proximity to fans, windows, doors, and ventilation 

systems; 4) damage to the case; and 5) location of case within the pallet (e.g., top/not load-bearing, 

bottom/load-bearing).

For stockpiles where temperature and percent relative humidity (%RH) were monitored, NIOSH reviewed 

data that were provided by the facility stockpile managers. Where data were not available, NIOSH collected 

temperature and %RH data by placing data loggers in the facility, collecting temperature and %RH data for 

eight to 12 months (specifics provided in a later section). The temperature and %RH data were collected 

within two years of the surgical gowns being tested.

Collection of Surgical Gown Samples

• Surgical gowns classified as Level 3 per the standard ANSI/AAMI PB70:2012 Liquid Barrier Performance 

and Classification of Protective Apparel and Drapes Intended for Use in Health Care Facilities (herein 

referred to as AAMI PB70)—were collected from six stockpile facilities in 2019. Specifically, two models 

were selected, because they were the only Level 3 surgical gown models available for sampling by these 

six facilities: 1) Medline Proxima Aurora model and 2) Cardinal Health Astound model.1

• The gowns collected were from 16 production lots, which were all manufactured in 2008. Of these 16 

sampled lots, 4 lots had shelf lives designated by Cardinal Health Astound on the product packaging at 

the time of testing—all of these lots exceeded their five-year shelf lives. No storage condition 

recommendations were on the product packaging.

• Where possible, at least two production lots were sampled for each gown model within a facility. These 

two lots (designated Lot A and Lot B) were sampled to evaluate and attempt to account for possible

inter-lot variation. One lot (designated Lot A) was sampled when there was only one lot available for 

sampling.

• NIOSH researchers visited each facility and collected gown products which were shipped to the NIOSH 

facility overnight to reduce exposure to non-climate-controlled conditions during transport. NIOSH 

tested the gowns at its facility or had them tested by a third-party laboratory accredited to run the test 

method. 

• A minimum of 64 gowns were sampled and tested from each production lot to cover the tests required 

by the AAMI PB70 standard for Level 3 surgical gowns.

• Non-stockpiled (used as a control) surgical gowns of the same model as those collected from the six 

facilities were purchased from the open market. Two lots of each non-stockpiled model were purchased. 

The Medline Proxima Aurora non-stockpiled gowns did not have expiration date or storage condition 

information on the packaging; all non-stockpiled gowns were manufactured in 2018.

2 The Cardinal 

Health Astound had five-year expiration dates on the packaging; no Cardinal Health-recommended

storage condition information was on the product packaging.

1 Level 4 surgical gowns were also collected, and results will be published in a separate report.

2 Medline stated that it does not provide specific shelf life recommendations for this model [Medline 2020].
4

Characteristics of Sampled Surgical Gowns

• Table 1 provides a summary of the Level 3 surgical gown models sampled from the six facilities. The 

table also includes relevant shelf life status information. Surgical gowns are cleared by the Food and 

Drug Administration (FDA). The FDA does not require manufacturers to designate a shelf life, although 

some may choose to do so. 

• Testing for the stockpiled gowns was completed in 2019 and samples were tested within one year of 

collection. 

Table 1. Characteristics of the Level 3 surgical gowns sampled from six of the ten collaborating stockpile 

facilities—the other four facilities participated in the APR testing but did not stockpile Level 3 surgical gowns.

Stockpile 

Facility #3 Model Lot #4 Mfr. Year # of Gowns 

Tested

Gown Age at 

Time of Testing 

(2019, years)

Shelf Life Status on 

Packaging5

1 

Medline Proxima Aurora A 2008 64 11 Not designated (ND)

B 2008 64 11 ND

Cardinal Health Astound 

A 2008 64 11 Exp. 11/2013; past 5-year 

shelf life

B 2008 64 11 Exp. 11/2013; past 5-year 

shelf life

2 Medline Proxima Aurora A 2008 506 11 ND

B 2008 64 11 ND

4 

Medline Proxima Aurora A 2008 64 11 ND

B 2008 64 11 ND

Cardinal Health Astound A 2008 64 11 ND

B 2008 64 11 ND

6 

Medline Proxima Aurora A 2008 64 11 ND

B 2008 64 11 ND

Cardinal Health Astound A 2008 807 11 Exp. 04/2013; past 5-year 

shelf life

7 Cardinal Health Astound A 2008 787 11 Exp. 12/2013; past 5-year 

shelf life

10 Medline Proxima Aurora A 2008 64 11 ND

B 2008 64 11 ND

Evaluation of Spray Impact Penetration and Hydrostatic Water Resistance Performance

• NIOSH followed the required testing as outlined in AAMI PB70 for both non-stockpiled and stockpiled 

gowns (Table 2). AAMI PB70 is a standard that defines liquid barrier performance and classification of 

protective apparel used in healthcare facilities [ANSI/AAMI PB70 2012]. This includes test methods from 

the American Association of Textile Chemists and Colorists (AATCC) and the American Society for Testing 

and Materials (ASTM), as outlined in Table 2. AAMI PB70 defines the critical zone of a surgical gown 

3 Stockpile facility numbering reflects the numbering used for all ten stockpile facilities in NIOSH’s research study: 

https://www.cdc.gov/niosh/npptl/ppecase.html 4 Where possible, at least two production lots were sampled for each gown model within a facility. Gowns sampled from “Lot A” came 

from one production lot; gowns sampled from “Lot B” came from a second production lot.

5 Testing was completed in 2019. ND=expiration date not designated on the product packaging. 6 Not enough gown units were available for sampling. 7 More than 64 gowns were tested from Lot A as only one lot was available for sampling; sample size was based on available gowns 

within the cases collected samples. More tie samples were tested for hydrostatic resistance as this was the more stringent test to 

evaluate performance compared to spray impact.
5

shall, at a minimum, comprise the front area of the gown from chest to knees and the sleeves from the 

cuff to above the elbow. Cardinal Health identified the sleeve seam, chest area, and point of 

attachments in the front of the gown (e.g., tie attachment) as the critical zones for surgical gowns in this 

study. Medline identified the chest and sleeve seams as critical zones (CZ), but the tie attachments are 

NOT designated by this manufacturer as a CZ. However, the tie attachments were evaluated as an 

exploratory effort as the tie attachment area has the potential to move into the front gown area CZ 

based on the size of the healthcare personnel; the tie attachments are herein referred to as “tie 

attachment samples” and the results of these Medline tie attachment samples are presented in 

separate tables. 

• Spray Impact (AATCC 42) indicates how well the fabric resists strikethrough when fluids splash or spray 

onto the fabric, whereas Hydrostatic Resistance (AATCC 127) indicates how well the fabric will resist 

strikethrough when water pressure is applied to the surface of the fabric. 

Table 2. Minimum performance requirements as outlined in AAMI PB70 used to evaluate Level 3 surgical gown 

performance8

Test Method

AAMI PB70 Pass/Fail Criteria for 

Critical Zones9 of the Level 3 

Surgical Gowns

AATCC 42: Spray Impact Penetration Blotter weight ≤ 1.0 g H2O 

AATCC 127: Hydrostatic Pressure Resistance ≥ 50 cm H2O 

Evaluation of Non-stockpiled Surgical Gowns

• A summary of the non-stockpiled gown testing that was performed is shown in Table 3. Testing for the 

non-stockpiled gowns was completed from 2018 to 2019. The non-stockpiled gowns were also tested in 

accordance with performance requirements outlined in AAMI PB70. 

• Table 3 displays the number of samples tested for each critical zone (CZ) and tie attachment samples 

tested from each lot.

Table 3: Summary of the Critical Zones (CZs) Tested from the Non-stockpiled Surgical Gowns 

Non-stockpiled

Model

Lot # (Mfr. 

Year) Total # of Gowns Tested Total Number of CZ SamplesTested for Spray Impact10

Total Number of CZ Samples

Tested for Hydrostatic Resistance

Medline Proxima 

Aurora

A (2018) 64 64 64

B (2018) 64 64 64

Cardinal Health 

Astound

A (2018) 64 96 96

B (2018) 64 96 96

8 Testing the entire front of the gown and the areas of sleeve outside of the critical zones to evaluate conformance to Level 1 was not 

included in the described test plan except for the Medline Proxima Aurora gowns, where Medline stated the tie attachments were not 

considered critical zones, and therefor Spray Impact was evaluated against the tie attachments to confirm Level 1 requirements were 

meant and hydrostatic resistance was not evaluated. 9 These pass/fail criteria were also used when evaluating the Medline tie attachment samples. 10 32 gowns were evaluated per test, per production lot. For Spray Impact, three critical zones were tested per gown for a total of 96 

critical zones evaluated per lot (i.e., 32 chest, 32 tie attachment, 32 sleeve seam). For Hydrostatic Resistance, three critical zones were 

tested per gown for a total of 96 critical zones evaluated per lot (i.e., 32 chest, 32 tie attachment, 32 sleeve seam) for the Cardinal Health 

Astound model, while two critical zones were tested per gown for a total of 64 critical zones evaluated per lot (i.e., 32 chest, 32 sleeve 

seam) and 32 tie attachment samples for the Medline Proxima Aurora Model.
6

Table 4: Summary of the Tie Attachment Samples (non-Critical Zones) Tested from the Non-stockpiled Surgical 

Gowns 

Non-stockpiled 

Model

Lot # (Mfr. 

Year) Total # of Gowns Tested

Total Number of Tie 

Attachment Samples Tested 

for Spray Impact11

Total Number of Tie Attachment 

Samples Tested for Hydrostatic 

Resistance

Medline Proxima 

Aurora

A (2018) 32 32 32 

B (2018) 32 32 32

Evaluation of Stockpiled Surgical Gowns

A summary of the stockpiled gown testing for the Medline and Cardinal Health critical zones that was performed 

is shown in Table 5. A summary of the stockpiled gown testing for the Medline tie attachment samples that 

was performed is shown in Table 6. 

11 32 gowns were evaluated per test, per production lot. For Spray Impact, three critical zones were tested per gown for a total of 96 

critical zones evaluated per lot (i.e., 32 chest, 32 tie attachment, 32 sleeve seam). For Hydrostatic Resistance, three critical zones were 

tested per gown for a total of 96 critical zones evaluated per lot (i.e., 32 chest, 32 tie attachment, 32 sleeve seam) for the Cardinal Health 

Astound model, while two critical zones were tested per gown for a total of 64 critical zones evaluated per lot (i.e., 32 chest, 32 sleeve 

seam) and 32 tie attachment samples for the Medline Proxima Aurora Model.
7

Table 5: Summary of the Testing Conducted on the Stockpiled Level 3 Surgical Gown Critical Zones. 

 

Stockpile 

Facility #12

Model Lot # Mfr. 

Year 

Total # of 

Gowns Tested Notes on CZ13 Sample Size for each Production Lot

1 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact CZs

32 chest, 32 sleeve seam

Hydrostatic CZs 

32 chest, 32 sleeve seam

B 2008 64 

Cardinal 

Health 

Astound

A 2008 64 Spray Impact CZs

32 chest, 32 tie attachment, 32 sleeve seam

Hydrostatic CZs 

32 chest, 32 tie attachments, 32 sleeve seam

B 2008 64 

2 

Medline 

Proxima 

Aurora

A 2008 5014

Stockpile did not have a sufficient number of gown samples to support 

the test plan. Testing for Hydrostatic Resistance is more stringent and 

prioritized over Spray Impact testing.

Spray Impact CZs

64 (32 chest, 32 sleeve seam)

Hydrostatic CZs 

32 chest, 32 sleeve seam

B 2008 64 

Spray Impact CZs

32 chest, 32 sleeve seam

Hydrostatic CZs

32 chest, 32 sleeve seam

4 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact CZs

32 chest, 32 sleeve seam

Hydrostatic CZs 

32 chest, 32 sleeve seam

B 2008 64 

Cardinal 

Health 

Astound

A 2008 64 Spray Impact CZs

32 chest, 32 tie attachments, 32 sleeve seam

Hydrostatic CZs 

32 chest, 32 tie attachments, 32 sleeve seam

B 2008 64 

6 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact CZs

32 chest, 32 sleeve seam

Hydrostatic CZs 

32 chest, 32 sleeve seam

B 2008 64 

Cardinal 

Health 

Astound

A 2008 80 

Stockpile only had one production lot available for sampling; therefore, 

additional samples were tested from this single production lot. 

Spray Impact CZs

128 (48 chest, 32 tie attachment, 48 sleeve seam)

Hydrostatic CZs 

144 (48 chest, 48 tie attachment, 48 sleeve seam)

7 

Cardinal 

Health 

Astound

A 2008 78

Stockpile only had one production lot available for sampling; therefore, 

additional samples were tested from this single production lot.

Spray Impact CZs

124 (46 chest, 32 tie attachment, 46 sleeve seam)

Hydrostatic CZs

138 (46 chest, 46 tie attachment, 46 sleeve seam)

10 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact CZs

32 chest, 32 sleeve seam

Hydrostatic CZs

32 chest, 32 sleeve seam

B 2008 64 

12 Stockpile facility numbering reflects the numbering used for all ten stockpile facilities in NIOSH’s research study. 

https://www.cdc.gov/niosh/npptl/ppecase.html 13 Medline does not consider the tie attachments as critical zones. 14 Not enough product cases were available for sampling. 
8

Table 6: Summary of the Testing Conducted on the Stockpiled Medline Proxima Aurora Surgical Gown Tie 

Attachment Samples.

Stockpile 

Facility #15 Model Lot # Mfr. 

Year

Total # of 

Gowns Tested Notes on Tie Attachment Sample Size for each Production Lot

1 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact 

32 tie attachments 

Hydrostatic

32 tie attachments

B 2008 64 

2 

Medline 

Proxima 

Aurora

A 2008 5016

Stockpile did not have a sufficient number of gown samples to support 

the test plan. Testing for Hydrostatic Resistance is more stringent and 

prioritized over Spray Impact testing.

Spray Impact17

18 tie attachment

Hydrostatic

32 tie attachments

B 2008 64 

Spray Impact

32 tie attachments

Hydrostatic

32 tie attachments

4 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact

32 tie attachments

Hydrostatic 

32 tie attachments

B 2008 64

B 2008 64

6 

Medline 

Proxima 

Aurora

A 2008 64 Spray Impact

32 tie attachments

Hydrostatic

32 tie attachments

B 2008 64 

10 

Medline 

Proxima 

Aurora

A 2008 64 

Spray Impact

32 tie attachments

Hydrostatic

32 tie attachments

What NIOSH Found Through Inspection, Testing, and Evaluation 

Storage Conditions

• Facility-specific findings—such as site and pallet storage conditions—can be found in the series of 

individual PPE CASE Reports developed to document the APR testing results for each of the six facilities 

[Greenawald et al. 2020a-f]. 

• A brief synopsis of storage conditions found at each of the six facilities where surgical gowns were 

sampled is presented in Table 5. PPE manufacturers may recommend temperature and %RH storage 

recommendations over the life of the product to minimize loss of performance.

15 Stockpile facility numbering reflects the numbering used for all ten stockpile facilities in NIOSH’s research study. 

https://www.cdc.gov/niosh/npptl/ppecase.html 16 Not enough cases were available for sampling. 17 Since only one tie attachment sample is available per gown, conducting hydrostatic resistance testing for tie attachments was

prioritized over conducting spray impact testing for tie attachments. 
9

• Temperature and %RH data were available/obtained for the following lengths of time for each facility:

o Facility 1: 2 years 11 months (facility-generated data; 2014 - 2017) 

o Facility 2: 2 years 11 months (facility-generated data; 2014 - 2017) 

o Facility 4: 1 year (NIOSH data logger-generated data; 2017 - 2018) 

o Facility 6: 3 years 10 months (facility-generated data; 2013 - 2017) 

o Facility 7: 1 year (NIOSH data logger-generated data; 2017 - 2018) 

o Facility 10: 5 years (facility-generated data; 2014 - 2019) 

• Figures 2 and 3 show the minimum, maximum, and average temperature and %RH, respectively, for 

each of the six collaborating stockpiles across the specified time frame. Facility-specific temperature and 

%RH data plots over time can be found in the series of six PPE CASE reports that were completed for the 

APRs tested from these facilities [Greenawald et al. 2020a-f].
10

Table 7: Summary of the Storage Characteristics at the Six Stockpile Ffacilities. 

Stockpile 

Facility

Level 3 

Gown 

Models

Storage Characteristics

Environmental 

Controls and 

Monitoring

Visual Inspection 

Concerns for

Cases or Gowns

1 

Medline 

Proxima 

Aurora

Cardinal 

Health 

Astound

Lighting off when unoccupied; no evidence of excess 

moisture or chemical spills; no windows allowing 

sunlight; pallets shrink wrapped on pallet sides but not 

top or bottom; some pallets were stacked two pallets 

high on the topmost rack, causing some weight to be 

applied to the bottom pallet

Temperature 

controlled; 

temperature and 

%RH monitored

Cases: 4 cases with 

slight crushing, 

puncture, or tears

Gowns: None

2 

Medline 

Proxima 

Aurora

Warehouse shared with another entity; lighting off when 

unoccupied; no evidence of excess moisture or chemical 

spills; no windows allowing sunlight; pallets shrink 

wrapped on pallet sides but not top or bottom; pallets 

separated by metal rack

Temperature 

controlled; 

temperature and 

%RH monitored

Cases: 1 case with 2 

small punctures/tears

Gowns: None

4 

Medline 

Proxima 

Aurora

Cardinal 

Health 

Astound

Lighting off when unoccupied; small ceiling vents 

allowed sunlight to enter facility; no evidence of excess 

moisture or chemical spills; pallets shrink wrapped on 

pallet sides but not top or bottom; some pallets were 

stacked two pallets high on the top most rack, causing 

some weight to be applied to the bottom pallet

Temperature 

controlled; 

temperature and 

%RH not 

monitored

Cases: 8 cases with 

slight to moderate 

tears/punctures

Gowns: None

6 

Medline 

Proxima 

Aurora

Cardinal 

Health 

Astound

Lighting off when unoccupied; no evidence of excess 

moisture or chemical spills; no windows allowing 

sunlight; ceiling fans circulated air; pallets shrink 

wrapped on pallets sides and the top; pallets separated 

by metal rack

Temperature and 

%RH controlled; 

temperature and 

%RH 

intermittently 

monitored

Cases: 2 cases with 

slight to large 

tears/punctures

Gowns: None

7 

Cardinal 

Health 

Astound

Lighting off when unoccupied; no evidence of chemical 

spills; evidence of mitigated moisture damage on 

facilities walls; some windows allowed indirect sunlight; 

pallets shrink wrapped on sides and a plastic covering 

was placed on the top; pallets separated by metal rack

No controls or 

monitoring

Cases: 2 cases with 

slight crushing on one 

side

Gowns: None

10 

Medline 

Proxima 

Aurora

Lighting off when unoccupied; no evidence of excess 

moisture or chemical spills; no windows allowing 

sunlight; pallets shrink wrapped on sides but not top or 

bottom; pallets separated by metal rack

Temperature 

controlled; 

temperature and 

%RH monitored

Cases: 3 cases with 

slight tear/puncture 

to side and crushing 

to corner

Gowns: None
11

Figure 2: Average, minimum, and maximum temperature for the six stockpile facilities visited in this study. HHS 

regions for each facility are also depicted; refer to Figure 1 for the HHS region locations.

Figure 3: Average, minimum, and maximum %RH for the six stockpile facilities visited in this study. HHS regions 

for each facility are also depicted; refer to Figure 1 for the HHS region locations.
12

• Case and Gown Visual Inspections—Visual inspection concerns were recorded for factors that may affect 

surgical gown performance. These included damage to the gown case (e.g., crushing, open cases) and

damage to the gown, such as rips, tears, or cuts to the gown, as well as any appearance of mold and 

odor. Examples of visual inspection concerns to the product cases are shown in Figure 4. Overall, 1,040 

stockpiled Level 3 gowns were sampled from 48 cases; 20 cases (41.7%) showed some level of damage 

(e.g., crushing, tearing). A summary of these results can be seen in Table 5. As part of the visual 

inspection, seal leak detection of the packaging was evaluated using ASTM F1929: Detecting Seal Leaks 

in Porous Medical Packing by Dye Penetration. Method B (Edge Dip Method) was used. A pictorial

example of this method is shown in Figure 5. No individual gown visual inspection concerns were noted

(e.g., odor, holes), nor any gown packaging/seal leak issues.

 

Figure 4: Examples of visual inspection concerns to the surgical gown cases including crushing and ripping to the 

product packaging.
13

Figure 5: Example of the ASTM F1929 seal leak test conducted for each non-stockpiled and stockpiled 

surgical gown.

As part of an exploratory effort, a total of 320 Medline Proxima Aurora tie attachment samples were evaluated. 

Medline did not consider the tie attachment to be in the critical zone, but were evaluated by NIOSH in the event 

these attachments moved to the front area of the gown if incorrectly sized or improper size selection occurred

These results will be presented in the subsequent section.

Level 3 Surgical Gown Performance by Critical Zone (Medline Proxima Aurora and Cardinal Health Astound)

• In total, 1,040 stockpiled Level 3 gowns were sampled. A total of 2,888 critical zones were tested from 

these gowns for spray impact and hydrostatic resistance. The AAMI PB70 standard requires 

manufacturers to implement a quality system that rejects lots with a failure rate greater than or equal to 

20% at least 90% of the time (β=0.10). This is known as the rejectable quality level (RQL), which defines 

the fraction defective of a lot that will have a small probability of being accepted [ANSI/AAMI PB70 

2012]. When using the sample size example provided in the standard of 32 gowns tested per production 

lot per test, the allowable failure rate must be adjusted to give a 90% confidence interval. With a 90% 

confidence interval, a lot with 20% or more of failures has up to a 10% chance of being accepted. With 

that condition, a maximum of 3 failures out of 32 tests (i.e., 9.4%) are permitted within a critical zone. 

• AAMI PB70 is primarily designed to be used by device manufacturers in qualifying, classifying, and 

labeling the performance of their products so healthcare personnel “can make informed decisions when 

selecting the appropriate product for the anticipated task at hand”, and quality assurance (e.g., to verify 

production lot quality when received) is specifically an exclusion of this standard [ANSI/AAMI PB70 

2012]. This standard allows a manufacturer to evaluate production quality in a continuous manner.

Production lot size was not available. Therefore, the data in this study cannot be used to definitively 

determine whether the production lots evaluated should be “rejected” or “accepted.” The data in this 

study may only be used to determine whether evidence supports that a quality issue may exist and 

warrants further exploration by the manufacturer. Therefore, AAMI PB70 was used as a general guide to 

interpret the findings within each critical zone type (i.e., chest, tie, and seam) of the set of 32 critical 

zone samples tested (i.e., one set of critical zones per gown sampled). 
14

• To simplify the interpretation, NIOSH created a red/yellow/green “stoplight analogy” based on the RQL 

and levels of concern, which is shown in Table 8 [adapted from NIOSH 2017b; NIOSH 2018]. Green is for 

critical zones that have failure rates well below the RQL; yellow is an intermediate status where 

additional testing may be advisable; and red is for a failure rate potentially higher than the RQL, 

indicating the gowns may not provide the expected level of protection. This analogy was applied to

samples within a critical zone type. For an evaluation of 32 samples within a critical zone (e.g., chest 

area), NIOSH considered 0-2 failures (i.e., failure rate <6.3%) as green, 3 failures (i.e., failure rate=9.4%) 

as yellow, and >4 failures (i.e., failure rate >12.5%) as red. 

• For several test groups, more than 32 samples were tested within a critical zone. The number of failures 

corresponding to each color in the stoplight analogy was adjusted based on the total samples tested. 

Table 8: Red/yellow/green criteria selected for sets of 32 critical zones (CZ) at 20% RQL per AATCC test

method

CZ Failure Rate

# of Failures 

within a Single 

CZ Type

CZ Interpretation

Red

Potentially higher 

than RQL, β=0.1 

(i.e., sample failure 

rate >12.5%)

>4 of 32 CZ

STRONGLY INDICATES QUALITY ISSUES 

MAY EXIST AND RESAMPLING MAY BE 

NECESSARY

Yellow

Intermediate 

condition

(i.e., sample failure 

rate=9.4%)

3 of 32 CZ INDICATES QUALITY ISSUES MAY EXIST 

AND RESAMPLING MAY BE BENEFICIAL

Green

Significantly lower 

than RQL β=0.1

(i.e., sample failure 

rate ≤6.25%)

0-2 of 32 CZ DOES NOT INDICATE QUALITY ISSUES 

• Spray Impact (AATCC 42)

o Non-stockpiled gowns—A summary of the spray impact testing results for the non-stockpiled

Level 3 surgical gowns can be seen in Table 9. A total of 128 chest, 64 tie attachments, and 128 

sleeve seam non-stockpiled critical zone samples were tested. 

 All sample sets from each of the four non-stockpiled gown production lots met the 

AAMI PB70 performance requirements—i.e., no more than three critical zone samples

failed within each critical zone type and within each production lot.
15

Table 9: Summary of Spray Impact (AATCC 42) Test Results for Non-stockpiled (Control) Level 3 Surgical Gowns

by Critical Zone (CZ)

Spray Impact: Non-stockpiled Gowns (Controls)

Gown Model CZ Total Tested # CZ Failing Test 

Criteria in Table 2

CZ Interpretation

Based on # of CZ 

Failures

Medline Proxima Aurora

Lot A (Mfr. 01/2018)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

Lot B (Mfr. 03/2018)

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

Lot A (Mfr. 04/2018)

Chest 32 0 Green

Tie 32 2 Green

Seam 32 0 Green

Cardinal Health Astound

Lot B (Mfr. 05/2018)

Chest 32 0 Green

Tie 32 0 Green

Seam 32 0 Green

o Stockpiled Gowns—A summary of the spray impact testing results for the stockpiled Level 3 

surgical gowns can be seen in Table 10. 

 A total of 542 chest, 192 tie attachments18, and 542 sleeve seam critical zones were 

tested. 

 No quality issues were indicated among the sample sets tested from the 16 stockpiled 

production lots—i.e., no more than three failures within each critical zone type 

occurred within each production lot. However, the results for AATCC 127 (hydrostatic 

resistance, data provided below) must be considered in the final determination for the 

production lot. 

18 Since only one tie attachment is available per gown, conducting hydrostatic resistance testing for tie attachments was prioritized over 

conducting spray impact testing for tie attachments.
16

Table 10: Summary of Spray Impact (AATCC 42) Test Results for Stockpiled Level 3 Surgical Gowns by Critical Zone 

(CZ). 

Spray Impact: Stockpiled Gowns

Stockpile/Gown Model CZ Total Tested # CZ Samples Failing 

Test Criteria in Table 2

CZ Interpretation Based 

on # of CZ Failures

Medline Proxima Aurora

SP 1 Lot A (Mfr. 11/2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 1 Lot B (Mfr. 08/2008)

Chest 32 1 Green

Seam 32 0 Green

Cardinal Health Astound

SP 1 Lot A (Mfr. 2008)

Chest 32 0 Green

Tie 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 1 Lot B (Mfr. 2008)

Chest 32 0 Green

Tie 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 2 Lot A (Mfr. 11/2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 2 Lot B (Mfr. 07/2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 4 Lot A (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 4 Lot B (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 4 Lot A (Mfr. 2008)

Chest 32 0 Green

Tie 32 1 Green

Seam 32 0 Green

Cardinal Health Astound

SP 4 Lot B (Mfr. 2008)

Chest 32 0 Green

Tie 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 6 Lot A (Mfr. 06/2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 6 Lot B (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 6 Lot A (Mfr. 2008)

Chest 48 0 Green

Tie 32 0 Green

Seam 48 0 Green

Cardinal Health Astound

SP 7 Lot A (Mfr. 2008)

Chest 46 0 Green

Tie 32 0 Green

Seam 46 0 Green

Medline Proxima Aurora

SP 10 Lot A (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 10 Lot B (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

• Hydrostatic Resistance (AATCC 127)

o Non-stockpiled Gowns—A summary of the hydrostatic resistance testing results for the nonstockpiled Level 3 surgical gowns can be seen in Table 11. A total of 128 chest CZ, 64 tie 

attachments CZ, and 128 sleeve seams non-stockpiled CZ samples were tested. Testing for one 

production lot strongly indicated quality issues (9 seam failures), and testing for a second 
17

production lot indicated quality issues may exist (3 seam failures). Testing for the remaining 

two production lots did not indicate any quality issues.

o The failure rates for both the Medline Proxima Aurora and Cardinal Health Astound nonstockpiled and stockpiled models when tested against AATCC 42 are shown in Figures 6 and 7, 

respectively. Additionally, Tables A1 and A2 in the Appendix provide more detail on the failure 

rates for these models.

Table 11: Summary of Hydrostatic Resistance (AATCC 127) Test Results for Non-stockpiled (Control) Level 3 

Surgical Gowns by Critical Zone (CZ). 

Hydrostatic Resistance: Non-Stockpiled Gowns

Gown Model CZ Total Tested # CZ Samples Failing Test 

Criteria in Table 2

CZ Interpretation Based 

on # of CZ Failures

Medline Proxima Aurora

Lot A (Mfr. 01/2018)

Chest 32 0 Green

Seam 32 1 Green

Medline Proxima Aurora

Lot B (Mfr. 03/2018)

Chest 32 0 Green

Seam 32 9 Red

Cardinal Health Astound

Lot A (Mfr. 04/2018)

Chest 32 1 Green

Tie 32 1 Green

Seam 32 0 Green

Cardinal Health Astound

Lot B (Mfr. 05/2018)

Chest 32 1 Green

Tie 32 2 Green

Seam 32 3 Yellow

o Stockpiled Gowns—A summary of the hydrostatic resistance testing results for the stockpiled 

Level 3 surgical gowns can be seen in Table 12. 

 A total of 542 chest, 222 tie attachments, and 542 sleeve seam critical zones were 

tested. 

 Testing for 1 of the 16 stockpiled production lots strongly indicated that quality issues 

exist (8 chest failures). The remaining production lots tested did not indicate any 

quality issues. 

 The percent failure rates for both the Medline Proxima Aurora and Cardinal Health 

Astound non-stockpiled and stockpiled models when tested against AATCC 127 are 

shown in Figures 6 and 7, respectively. Additionally, Tables A3 and A4 in the Appendix 

provide more detail on the percent failure rates for these models. The percent critical 

zones not meeting AATCC 127 criteria are shown in comparison to the failure rate of

12.5% as the threshold of strongly indicating a quality issue based on 4+ critical zone

failures out of 32 within one critical zone type. 
18

Table 12: Summary of Hydrostatic Resistance (AATCC 127) Test Results for Level 3 Stockpiled Surgical Gowns by 

Critical Zone (CZ). 

Hydrostatic Resistance: Stockpiled Gowns

Stockpile/Gown Model CZ Total Tested # CZ Samples Failing 

Test Criteria in Table 2

Interpretation Based 

on # of CZ Sample

Failures

Medline Proxima Aurora

SP 1 Lot A (Mfr. 11/2008)19

Chest 32 2 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 1 Lot B (Mfr. 08/2008)

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 1 Lot A (Mfr. 2008)

Chest 32 8 Red

Tie 32 1 Green

Seam 32 0 Green

Cardinal Health Astound

SP 1 Lot B (Mfr. 2008)

Chest 32 0 Green

Tie 32 1 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 2 Lot A (Mfr. 11/2008)

Chest 32 0 Green

Seam 32 1 Green

Medline Proxima Aurora

SP 2 Lot B (Mfr. 07/2008)

Chest 32 0 Green

Seam 32 2 Green

Medline Proxima Aurora

SP 4 Lot A

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 4 Lot B

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 4 Lot A

Chest 32 0 Green

Tie 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 4 Lot B

Chest 32 1 Green

Tie 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 6 Lot A (Mfr. 06/2008)

Chest 32 2 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 6 Lot B

Chest 32 0 Green

Seam 32 0 Green

Cardinal Health Astound

SP 6 Lot A20

Chest 48 0 Green

Tie 48 5 Green

Seam 48 0 Green

Cardinal Health Astound

SP 7 Lot A (Mfr. 2008)14

Chest 46 2 Green

Tie 46 2 Green

Seam 46 0 Green

Medline Proxima Aurora

SP 10 Lot A (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

Medline Proxima Aurora

SP 10 Lot B (Mfr. 2008)

Chest 32 0 Green

Seam 32 0 Green

19 Medline Proxima Aurora Lot A from SP 1 and SP 2 are the same production lot.

20 NIOSH’s stoplight analogy was adjusted for these lots with an increased sample size. With a sample size of 48 CZ samples within a CZ 

type, <5 CZ failures are permitted within an RQL of 20% (β=0.1). With a sample size of 46 CZ samples within a CZ type, up to <5 CZ failures 

are permitted within an RQL of 20% (β=0.1). 
19

Figure 6: Percent of Medline Proxima Aurora critical zone samples failing hydrostatic resistance test criteria in 

Table 2.
20

Figure 7: Percent of Cardinal Health Astound critical zone samples failing hydrostatic resistance test criteria in 

Table 2. *See footnote 21.

Tie Attachment Sample Performance (Medline Proxima Aurora) 

o Non-stockpiled gowns—A summary of the spray impact testing results for the non-stockpiled

Medline Proxima Aurora surgical gown tie attachment samples can be seen in Table 13. A total 

of 64 non-stockpiled tie attachment samples were tested. 

 All sample sets from each of the four non-stockpiled gown production lots met the 

AAMI PB70 performance requirements—i.e., no more than three critical zone samples

failed within each critical zone type and within each production lot.

Table 13: Summary of Spray Impact (AATCC 42) Test Results for Non-stockpiled (reference) Medline Proxima 

Aurora Surgical Gown Tie Attachment Samples 

Spray Impact: Non-stockpiled Gowns (Controls)

Gown Model Sample Total Tested

# Tie Attachment 

Samples Failing 

Test Criteria in 

Table 2

Interpretation 

Based on # of 

Sample Failures

Medline Proxima Aurora

Lot A (Mfr. 01/2018) Tie 32 0 Green

Medline Proxima Aurora

Lot B (Mfr. 03/2018) Tie 32 1 Green

 

9.4% (3 samples): Indicates 

quality issues may exist and 

resampling may be beneficial; 

difficult to interpret.
21

o Stockpiled Gowns—A summary of the spray impact testing results for the stockpiled Medline 

Proxima Aurora surgical gown tie attachment samples can be seen in Table 14. 

 A total of 320 tie attachments samples21 were tested. 

 No quality issues were indicated among the sample sets tested from the 10 stockpiled 

production lots—i.e., no more than three failures within each critical zone type 

occurred within each production lot. However, the results for AATCC 127 (hydrostatic 

resistance, data provided below) must be considered in the final determination for the 

production lot.

Table 14: Summary of Spray Impact (AATCC 42) Test Results for Stockpiled Medline Proxima Aurora Surgical Gown

Tie Attachment Samples. 

Spray Impact: Stockpiled Gowns

Stockpile/Gown Model Sample Total Tested

# Tie Attachment 

Samples Failing Test 

Criteria in Table 2

Interpretation Based on 

# of Sample Failures

Medline Proxima Aurora

SP 1 Lot A (Mfr. 11/2008) Tie 32 0 Green

Medline Proxima Aurora

SP 1 Lot B (Mfr. 08/2008) Tie 32 0 Green

Medline Proxima Aurora

SP 2 Lot A (Mfr. 11/2008) Tie 32 0 Green

Medline Proxima Aurora

SP 2 Lot B (Mfr. 07/2008) Tie 32 0 Green

Medline Proxima Aurora

SP 4 Lot A (Mfr. 2008) Tie 32 0 Green

Medline Proxima Aurora

SP 4 Lot B (Mfr. 2008) Tie 32 0 Green

Medline Proxima Aurora

SP 6 Lot A (Mfr. 06/2008) Tie 32 0 Green

Medline Proxima Aurora

SP 6 Lot B (Mfr. 2008) Tie 32 0 Green

Medline Proxima Aurora

SP 10 Lot A (Mfr. 2008) Tie 32 0 Green

Medline Proxima Aurora

SP 10 Lot B (Mfr. 2008) Tie 32 0 Green

• Hydrostatic Resistance (AATCC 127)

o Non-stockpiled Gowns—A summary of the hydrostatic resistance testing results for the nonstockpiled Medline Proxima Aurora surgical gown tie attachment samples can be seen in Table 

15. A total of 64 tie attachments samples were tested. No quality issues were indicated among 

the sample sets tested from the 10 stockpiled production lots—i.e., no more than three

failures within each critical zone type occurred within each production lot. 

21 Since only one tie attachment is available per gown, conducting hydrostatic resistance testing for tie attachments was prioritized over 

conducting spray impact testing for tie attachments.
22

Table 15: Summary of Hydrostatic Resistance (AATCC 127) Test Results for Medline Proxima Aurora Surgical 

Gowns Tie Attachment Samples. 

Hydrostatic Resistance: Non-Stockpiled Gowns

Gown Model Sample Total Tested

# Tie Attachment 

Samples Failing Test 

Criteria in Table 2

Interpretation Based on 

# of Tie Attachment

Sample Failures

Medline Proxima Aurora

Lot A (Mfr. 01/2018) Tie 32 0 Green

Medline Proxima Aurora

Lot B (Mfr. 03/2018) Tie 32 2 Green

o Stockpiled Gowns—A summary of the hydrostatic resistance testing results for the stockpiled 

Level 3 surgical gowns can be seen in Table 16. 

 A total of 320 tie attachment samples were tested. 

 Testing for 5 of the 10 (50%) stockpiled production lots strongly indicated that quality 

issues exist (see all “red” critical zone interpretations). The remaining 50% of the 

production lots tested did not indicate any quality issues. 

 The percent failure rates for the Medline Proxima Aurora non-stockpiled and stockpiled 

tie attachment samples when tested against AATCC 127 are shown in Figure 8.

Additionally, Tables A3 and A4 in the Appendix provide more detail on the percent

failure rates for these models. The percent critical zones not meeting AATCC 127 criteria 

are shown in comparison to the failure rate of 12.5% as the threshold of strongly 

indicating a quality issue based on 4+ critical zone failures out of 32 within one critical 

zone type.
23

Table 16: Summary of Hydrostatic Resistance (AATCC 127) Test Results for Medline Proxima Aurora Surgical 

Gowns Tie Attachment Samples. 

Hydrostatic Resistance: Stockpiled Gowns

Stockpile/Gown Model Sample Total Tested

# Tie Attachment 

Samples Failing Test 

Criteria in Table 2

Interpretation Based 

on # of Sample Failures

Medline Proxima Aurora

SP 1 Lot A (Mfr. 11/2008)22

Tie

Attachment 32 10 Red

Medline Proxima Aurora

SP 1 Lot B (Mfr. 08/2008)

Tie 

Attachment 32 4 Red

Medline Proxima Aurora

SP 2 Lot A (Mfr. 11/2008)

Tie 

Attachment 32 16 Red

Medline Proxima Aurora

SP 2 Lot B (Mfr. 07/2008)

Tie 

Attachment 32 9 Red

Medline Proxima Aurora

SP 4 Lot A

Tie 

Attachment 32 12 Red

Medline Proxima Aurora

SP 4 Lot B

Tie 

Attachment 32 0 Green

Medline Proxima Aurora

SP 6 Lot A (Mfr. 06/2008)

Tie 

Attachment 32 1 Green

Medline Proxima Aurora

SP 6 Lot B

Tie 

Attachment 32 0 Green

Medline Proxima Aurora

SP 10 Lot A (Mfr. 2008)

Tie 

Attachment 32 1 Green

Medline Proxima Aurora

SP 10 Lot B (Mfr. 2008)

Tie 

Attachment 32 0 Green

22 Medline Proxima Aurora Lot A from SP 1 and SP 2 are the same production lot.
24

Figure 8: Percent of Medline Proxima Aurora tie attachment samples failing hydrostatic resistance test criteria in 

Table 2.
25

CASE Findings

NIOSH evaluated a total of 1,040 Level 3 surgical gowns from six U.S. stockpile facilities. These gowns came from 

16 production lots from 2 surgical gown models: Medline Proxima Aurora and Cardinal Health Astound. All 

gowns were manufactured in 2008; only some lots had a 5-year expiration date information on the packaging at 

the time of sampling. 

Samples were taken from three critical zones on the gowns (i.e., the chest area, the tie attachment, and the 

sleeve seam) and were tested to two standard test methods per AAMI PB70 requirements: AATCC 42 (Spray 

Impact) and AATCC 127 (Hydrostatic Resistance). The critical zones defined in AAMI PB70 were considered for 

testing. For Cardinal Astound surgical gowns, critical zones included three areas (chest, sleeve seams, and tie 

attachments). For the Medline Aurora gowns, the manufacturer only considered the chest and sleeve seams as 

CZ. However, the tie attachments were still evaluated as an exploratory effort in the event these attachments 

moved to the front area of the gown if incorrectly sized or improper size selection occurred. A total of 3,208 

stockpiled gown critical zones or tie attachment samples were tested. Additionally, 256 non-stockpiled gowns 

(768 critical zone or tie attachment samples) were tested.

AAMI PB70 was the only barrier classification standard identified for surgical gowns in the United States [NIOSH 

2017b; NIOSH 2018]. Although it is possible for a third-party entity (e.g., federal or state stockpiles, hospitals) to 

use the barrier performance test methods outlined in AAMI PB70 (i.e., ASTM and AATCC test methods) in a postmarket application as was done in this study, it is difficult to draw conclusions related to quality since the 

current standard is not designed for that application as indicated by specific language that excludes using this 

standard for quality assurance interpretation (refer to Section 1.3 Exclusions, J of the standard). For this reason, 

NIOSH (and any other entity that desires post-market quality assurance information) was/is only able to 

determine if there is indication that a quality issue may exist – while additional sampling may increase 

confidence in any post-market decisions that are made by a third-party entity (e.g., federal, state, and local 

hospitals), no increase in sampling can result in that entity making a pass/fail determination for the larger 

population of product that this third-party received/purchased based on the samples tested. 

Findings for Gown and Case Visual Inspections 

• Overall, no individual surgical gown bags had visual inspection concerns nor any bag seal leak issues. 

Visual inspection concerns were noted for 20 of the 48 sampled cases, including crushing, punctures, 

and tears. No signs of mold or water damage to the gowns or gown cases were observed. 

Findings for the Medline Proxima Aurora Model

Chest and Seam Critical Zone Samples: Samples of this model were collected from five stockpiles. In total, 1,536

stockpiled (1,280) and non-stockpiled (256) critical zones samples were tested for spray impact and hydrostatic 

resistance. No stockpiled surgical gowns tested for spray impact (AATCC 42) or hydrostatic pressures (AATCC

127) indicated quality issues. However, one non-stockpiled (control) lot indicated quality issues when tested 

for hydrostatic pressure (AATCC 127). 

Tie Attachment Samples: In total, 1,768 stockpiled and non-stockpiled tie attachment samples were tested for 

spray impact and hydrostatic resistance. As part of this exploratory effort, the barrier performance of five of 

the 10 stockpiled surgical gown lots did not meet the requirements specified in the AAMI PB70 standard for 

hydrostatic resistance (AATCC 127). This may pose issues in the event of the tie attachment area moving to the 

front of the gown during improper size selection. 
26

Findings for the Cardinal Health Astound Model

• Samples of this model were collected from three stockpiles. In total, 1,686 stockpiled (1,302) and nonstockpiled (384) critical zone samples were tested for spray impact and hydrostatic resistance. Testing 

for spray impact (AATCC 42) did not indicate quality issues. However, when tested for hydrostatic 

pressure (AATCC 127), testing for 1 of the 6 (17%) stockpiled Cardinal Health Astound model 

production lots strongly indicated that quality issues exist, and one non-stockpiled lot strongly 

indicated quality issues. The barrier performance of the stockpiled surgical gowns did not meet the 

requirements specified in the AAMI PB70 standard which may be due to quality issues.

Additional Recommendations and Limitations

AAMI PB70 is designed to allow a manufacturer to evaluate production quality in a continuous manner, and 

quality assurance is specifically excluded in this standard (Section 1.3 Exclusions, J). Due to this limitation and 

limited number of production lots available for sampling from the stockpiles, NIOSH does not have enough 

information to definitively know the level of protection that may be provided by all stockpiled surgical gowns 

that 1) are stored for prolonged periods of times; 2) are stored under various storage conditions; or 3) have 

exceeded the manufacturer’s designated shelf life (if applicable). Meaning, the results are not generalizable 

across all stockpiled gowns from different models. 

Despite this limitation, the data shows instances where both the stockpiled (Cardinal Health Astound) and nonstockpiled (Medline Proxima Aurora) Level 3 surgical gowns sampled strongly indicate the potential for quality 

issues and the gowns may not offer the expected level of protection. A small number of reference gowns were 

evaluated.

Gowns of the same model sampled within the same stockpile facility showed inter-lot variability which may be 

related to quality control issues. For example, gowns sampled from select production lots of a particular model 

demonstrated a higher number of failures compared to units from a different lot of the same model, stored in 

the same facility. Furthermore, select models demonstrated a statistically significantly higher number of failures

when sampled from one facility but not from another with similar conditions and years of storage. 

Some of the non-stockpiled and stockpiled gowns evaluated in this study strongly suggested that a production 

quality issue may exist. Additionally, AAMI PB70 does not provide guidance for determining whether a new 

gown or a gown that has exceeded its shelf life will perform as expected. Therefore, NIOSH recommends that 

AAMI PB70 be expanded to include guidance for post-market quality assurance sampling and data interpretation 

for third party entities (e.g., stockpiles, hospitals, those conducting post-market surveillance activities to inform 

conformity assessment decision-makers, researchers, and entities attempting to identify potential counterfeit 

products). This expanded language should be designed to allow third party entities to objectively assess the 

conformance of the surgical gowns. The sampling plan specified in AAMI PB70 is not a standalone plan and is 

used in other standards (e.g., ISO 2859, ISO Z1.4); specifically, updates to AAMI PB70 should provide more 

sampling options and interpretation guidance for entities that may not know the entire production lot size for 

their surgical gowns. Further, revisions to AAMI PB70 to define minimum critical zone boundaries and include 

guidance for post-market quality assurance sampling and data interpretation for third party entities will enhance 

end user protections

Users that are provided any Level 3 surgical gowns that have been stored for prolonged periods (e.g., 5+ years) 

or are past their shelf life should be forewarned to avoid a false sense of confidence. Furthermore, these 

products should be considered to not be used for high-risk procedures that involve high amount of body fluids. 

As observed in this study, quality issues have also been previously reported for other “new/non-stockpiled” 

Level 3 and Level 4 surgical gowns [NIOSH 2017, NIOSH 2018] and isolation gowns [NIOSH 2015]. 
27

NIOSH does not recommend the use of gowns past their shelf life during routine, conventional use (i.e., where 

there are no supply shortages). We recommend contacting the manufacturers of the gowns in the stockpile with 

specific questions regarding the shelf life if it is not clearly visible on the product packaging and any potential use 

of the product past its shelf life during public health emergencies when extreme gown shortages may occur. For 

contingency capacity strategies during anticipated gown shortages, consideration can be given to using gowns 

past their manufacturer-designated shelf life for training purposes [CDC 2020]. ASTM F2407-20—a surgical gown 

standard updated in 2020 which establishes requirements for the performance, documentation, and labeling of 

surgical gowns in healthcare settings—specifies that surgical gown packages should include the use-by date 

[ASTM 2020]. 

What Can Stockpile Personnel and the PPE Community Do?

• Stockpile personnel should work with the manufacturers of the stockpiled products to address specific 

questions regarding shelf life and the use of product past its shelf life. The risks of using surgical gowns 

that have reached their shelf lives in an emergency should be evaluated and communicated to end 

users. If the stockpiled surgical gowns do not meet the relevant performance requirements, 

consideration can be given to relabeling and using these gowns for lower risk activities. The assessment 

of risk must be hazard-specific. 

• Because no consensus standard currently exists that enables third-party post-market evaluation and 

quality interpretation of surgical gowns to provide purchasers confidence in their expected 

performance, members of the PPE community should engage with standards development organizations 

to elevate the need to resolve this issue within these organizations. These organizations may include 

ANSI/AAMI, ASTM, and AATCC.

• The PPE community should consider how these findings should be integrated into the portfolio of 

surgical gown standards. 

• Proper size selection is important for surgical gowns to ensure non-critical zone areas of the gown are 

not moved into the critical zone areas during patient care. 

• To share experiences with or provide input to AAMI PB70, email ppeconcerns@cdc.gov as a coauthor is 

a NIOSH representative on this standard.

• Sign up for NPPTL’s Listserv at https://www.cdc.gov/niosh/npptl/sub-NPPTL.html to receive email 

notifications relevant to PPE, including webinar announcements, updated guidance releases, alerting 

users to an issue with a NIOSH Approved® respirator, and publication of federal register notices. 

For more information related to personal protective equipment, visit the NIOSH NPPTL website at 

https://www.cdc.gov/niosh/npptl/ 
28

Get More Information

Find NIOSH products and get answers to workplace safety and health questions:

1-800-CDC-INFO (1-800-232-4636) | TTY: 1-888-232-6348

CDC/NIOSH INFO: cdc.gov/info | cdc.gov/niosh

Monthly NIOSH eNews: cdc.gov/niosh/eNews

NIOSH Approved® is a registered certification mark of the U.S. Department of Health and Human Services (HHS).

All photos courtesy of NIOSH NPPTL.

Disclaimer 

The recommendations in this report are made based on the findings at the stockpiles evaluated and may not be applicable

to other stockpile facilities.

Mention of any company or product does not constitute endorsement by the National Institute for Occupational Safety and 

Health (NIOSH). In addition, citations to websites external to NIOSH do not constitute NIOSH endorsement of the

sponsoring organizations or their programs or products. Furthermore, NIOSH is not responsible for the content of these

websites. All web addresses referenced in this document were accessible as of the publication date.

Acknowledgements

The authors would like to acknowledge Dana Rottach for his assistance with the study design, interpretation of results, and 

statistical support related to AAMI PB70. The authors would also like to acknowledge Jim Harris, Christian Coby, Andrew

(Vlad) Wilson, and Brian Barker for their testing and evaluation support.

Suggested Citation 

NIOSH PPE CASE: Performance of Stockpiled Level 3 Surgical Gowns Sampled from Six Stockpile Facilities. By Lee A. 

Greenawald, Susan M. Moore, Selcen Kilinc-Balci, Patrick L Yorio. Pittsburgh, PA U.S. Department of Health and Human 

Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, NPPTL Report 

Number P2022-0101.

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31

Appendix

Table A1: Percent fail rates by lot for the Medline Proxima Aurora when tested against AATCC 42

Medline Proxima Aurora: Spray Impact (AATCC 42) % Fail Rates within a Lot

Non-stockpiled Stockpile 1 Stockpile 2 Stockpile 4 Stockpile 6 Stockpile 10

Lot # Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B

Chest CZ

# of 

Failures

0 0 0 1 0 0 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 0.00% 0.00% 0.00% 3.13% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Seam CZ

# of 

Failures

0 0 0 0 0 0 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Tie

Attachm

ent 

Samples

# of 

Failures

0 1 0 0 0 0 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 0.00% 3.13% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Table A2: Percent fail rates by lot for the Cardinal Health Astound when tested against AATCC 42

Cardinal Health Astound: Spray Impact (AATCC 42) % Fail Rates within a Lot

Non-stockpiled Stockpile 1 Stockpile 4 Stockpile 6 Stockpile 7

Lot # Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot A

Chest CZ

# of Failures 0 0 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 48 46

Fail Rate 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Seam CZ

# of Failures 0 0 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 48 46

Fail Rate 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Tie CZ

# of Failures 2 0 0 0 1 0 0 0

# of Tests 32 32 32 32 32 32 32 32

Fail Rate 6.25% 0.00% 0.00% 0.00% 3.13% 0.00% 0.00% 0.00%

Table A3: Percent fail rates by lot for the Medline Proxima Aurora when tested against AATCC 127

Medline Proxima Aurora: Hydrostatic Resistance (AATCC 127) % Fail Rates within a Lot1,2

Non-stockpiled Stockpile 1 Stockpile 2 Stockpile 4 Stockpile 6 Stockpile 10

Lot # Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot B

Chest CZ

# of 

Failures

0 0 2 0 0 0 0 0 0 2 0 0

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 0.00% 0.00% 6.25% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 6.25% 0.00% 0.00%

Seam CZ

# of 

Failures

1 9 0 0 2 1 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 3.13% 28.13% 0.00% 0.00% 6.25% 3.13% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Tie 

Attachm

ent 

Samples

# of 

Failures

0 2 10 4 9 16 12 0 0 1 0 2

# of Tests 32 32 32 32 32 32 32 32 32 32 32 32

Fail Rate 0.00% 6.25% 31.25% 12.50% 28.13% 50.00% 37.50% 0.00% 0.00% 3.13% 0.00% 6.25%
32

Table A4: Percent fail rates by lot for the Cardinal Health Astound when tested against AATCC 127

Cardinal Health Astound: Hydrostatic Resistance (AATCC 127) % Fail Rates within a Lot1,2

Non-stockpiled Stockpile 1 Stockpile 4 Stockpile 6 Stockpile 7

Lot # Lot A Lot B Lot A Lot B Lot A Lot B Lot A Lot A

Chest

CZ

# of Failures 1 1 8 0 0 1 0 2

# of Tests 32 32 32 32 32 32 48 46

Fail Rate 3.13% 3.13% 25.00% 0.00% 0.00% 3.13% 0.00% 4.35%

Seam

CZ

# of Failures 0 3 0 0 0 0 0 0

# of Tests 32 32 32 32 32 32 48 46

Fail Rate 0.00% 9.38% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00%

Tie CZ

# of Failures 1 2 1 1 0 0 5 2

# of Tests 32 32 32 32 32 32 48 46

Fail Rate 3.13% 6.25% 3.13% 3.13% 0.00% 0.00% 10.4% 4.35%