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Bates-Jensen Wound Assessment Tool (BWAT)

Bates-Jensen Wound Assessment Tool

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The Bates-Jensen Wound Assessment Tool (BWAT), formerly the Pressure Sore Status Tool (PSST), is a 15-item objective measure designed to assess wound status and track healing. It serves to assess the progression of[SC1]  wound healing. It is recommended that wounds are evaluated weekly or whenever a change is noted, and results can be plotted on the included Wound Status Continuum to monitor progress over time.

Acronym BWAT

Area of Assessment

General Health

Assessment Type



Not Free

Actual Cost


Key Descriptions

  • 15-items assessed by wound measurement and observations are performed. 13 scored items: size, depth, edges, undermining, necrotic tissue type and amount, exudate type and amount, skin color surrounding wound, peripheral tissue edema and induration, granulation tissue, and epithelialization. 2 non-scored items: location and shape of wound.
  • Item-level scores range from 1-5 on a modified Likert scale. Each item is scored for the wound characteristic it describes where 1 indicates least severe and 5 indicates most severe.
  • The 13 scored items are summed for a maximum total score of 65. Higher total scores indicate more severe wound status. The total score can be plotted on a linear “Wound Status Continuum” to track regeneration or degeneration of the wound over time. It is recommended that the BWAT be administered weekly to track wound status.
  • Detailed instructions are included for the provider with definitions of key terms and a description of assessment methods for each domain.

Number of Items

13 scored items

2 unscored items

Equipment Required

  • Measuring tape or ruler (in centimeters)
  • Long cottom swab
  • Paper form
  • Writing utensil
  • Transparent metric measuring guide with concentric circles divided into 4 (25%) pie-shaped quadrants (to determine the percent of wound involved by necrosis, exudate, epithelialization)

Time to Administer

5 minutes

98% of assessments completed within 5 minutes, with an average completion time of 1.6 minutes (Bates-Jensen et al., 2019).

Required Training

No Training

Instrument Reviewers

Original reviewers

Karen Coker, PT, DPT, CWS, FACCWS

Jennifer Burns, BA

Rachel Bond, BA


Updated in 2019 by 

Shawn Froelich, MS, MLS(ASCP)CM

Terri Beckwith, MPH, CCRP

Rochelle Bourassa, DPT, CLT-LANA, CWS

Body Part

Lower Extremity
Upper Extremity

ICF Domain

Body Structure
Body Function

Measurement Domain

General Health


The instrument was originally developed as the PSST in 1990 to assess pressure sores specifically. In 2001, it was renamed the BWAT to reflect its use assessing wounds of various etiologies. There were also some minor revisions in item scoring.

The tool has a one-page instruction sheet and item descriptions. A pictorial guide is available that includes 103 photographs of a variety of wound types and illustrates each descriptor of the BWAT items.

The BWAT, as noted with other tools of assessing wounds, should be utilized by individuals with adequate clinical experience, as validity and reliability can be compromised when the tool is administered by inexperienced users (Houghton et al., 2000).

A Turkish version has been validated  (Karahan et al., 2014)

Mixed Populations

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Cut-Off Scores

Pressure Ulcers: (Bates-Jensen et al, 2012)

  • BWAT Minimal Severity Scores 13-20
  • BWAT Mild Severity Scores 21-30
  • BWAT Moderate Severity Scores 31-40
  • BWAT Critical Severity Scores 41-65

Interrater/Intrarater Reliability

Mixed Population: (Bates-Jensen, Vredevoe & Brecht, 1992; n = 10; Mean Age = 67 [32-83]; Total Pressure Sores Assessed = 20; Retest Time = 1.5 hours; Medical-surgical patients in acute care hospital with pressure ulcers)

  • Excellent interrater reliability for total score (ICC = .91 at Time 1 and ICC = .92 at Time 2)
  • Excellent intrarater reliability for PSST total score (ICC = .99 for Rater 1 and .96 for Rater 2)


Mixed Population: (Bates-Jensen & McNees, 1995; n = 16)

  • Adequate interrater and intrarater reliability with pressure ulcers (ICC = 0.78 and 0.89) among a multidisciplinary group (PTs, LPNs, RNs) in the long-term care setting

Mixed population (Bates-Jensen et al., 2019; n = 1161 observations from nursing home residents, based on twelve wound assessment items)

  • Adequate interrater reliability for total BWAT item score, single observer (ICC = .58), ( .84 mean rating of observers)
  • Adequate interrater reliability for depth, single observer (ICC = .47), (.78 mean rating of observers)
  • Poor interrater reliability for edges, single observer (ICC = .38), (.71 mean rating of observers)
  • Adequate interrater reliability for undermining, single observer (ICC = .62), (.81 mean rating of observers)
  • Poor interrater reliability for necrotic tissue type, single observer (ICC = .38), (.71 mean rating of observers)
  • Poor interrater reliability for necrotic tissue amount, single observer (ICC = .37), (.70 mean rating of observers)
  • Adequate interrater reliability for exudate type, single observer (ICC = .44), (.76 mean rating of observers)
  • Adequate interrater reliability for exudate amount, single observer (ICC = .42), (.75 mean rating of observers)
  • Adequate interrater reliability for skin color surrounding wound, single observer (ICC = .54), (.83 mean  rating of observers)
  • Poor interrater reliability for peripheral tissue edema, single observer (ICC = .08), (.26 mean rating of observers)
  • Adequate interrater reliability for peripheral tissue induration, single observer (ICC = .42), (.75 mean rating of observers)
  • Adequate interrater reliability for granulation tissue, single observer (ICC = .47), (.78 mean rating of observers)
  • Adequate interrater reliability for epithelialization, single observer (ICC = .50), (.80 mean rating of observers)

Mixed Population (Karahan et al., 2014; Turkish sample)

  • Statistically significant relationship between wound care nurse experts and staff nurses (ꭕ2 = 1691.08; p < .001)

Internal Consistency

Pressure Ulcers: (Bates-Jensen, 1997; n = 113)

  • All 13 items on the PSST correlated with the total PSST.

Mixed population (Karahan et al., 2014; Turkish sample)

  • Excellent Cronbach’s alpha = .85

Criterion Validity (Predictive/Concurrent)

Concurrent validity:

Mixed Population: (Houghton et al, 2000; n = 46; Pressure and leg ulcers from patients in long-term care)

  • Excellent correlations of the 13-item PSST bedside assessment with the Photographic Wound Assessment Tool (PWAT) (r = 0.70)

Pressure Ulcers: (Bates-Jensen, 1997; n = 496 wounds assessed (Stage I [n = 23], Stage II [n = 211], Stage III [n = 195], Stage IV [n = 67]); Subset of individuals testing a computerized version of the PSST included in the WIS)

  • Adequate correlations between PSST total score and NPUAP stage score (r = 0.55, p = 0.001).

Pressure Ulcers: (Houghton et al, 2000; n = 46; Chronic ulcers)

  • High concurrent validity with the PWAT


Predictive validity


Mixed Population: (Bates-Jensen, 1998; n = 143 (partial thickness [n = 51], full thickness [n = 92]; Mean Age = 64.9 (18.03) years; Adults with at least three PSST assessments over a six-week period)

  • Excellent predictive validity for BWAT of 50% healing, as measured by surface area. Changes at 1 week in wound surface area were predictive of those wounds that achieved 50% healing during the six weeks monitored.
  • Excellent predictive validity for BWAT in 1-week net decrease (improvement) in score plus a decrease in surface area was the best predictor of time to 50% wound closure

Pressure Ulcers: (Bates-Jensen et al., 2019; n = 305 pressure ulcers from nursing home residents; Mean Age = 78 (14) years)

  • Initial BWAT score was a statistically significant predictor of pressure injury duration (less than 3 weeks vs. 3 weeks or greater) at the trunk (Wald ꭕ2 = 47.1, p < .001)
  • Initial BWAT score was a statistically significant predictor of resolved vs. persistent heel pressure injury damage (Wald ꭕ2 = 83.75, p < .001)


Construct Validity

Convergent Validity

Mixed Population: (Gardner, 2005; n = 32; Mean Age = 79.5 (15.60) years) 

  • Excellent convergent validity between the PSST and the Pressure Ulcer Scale for Healing (PUSH) at Week 1 (r = 0.72, n = 32), Week 2 (r = 0.76, n =32), Week 3 (r = 0.89, n = 26), Week 4 (r = 0.90, n = 24) and Week 5 (r = 0.95, n = 20)


Discriminant Validity

Pressure Ulcers: (Bates-Jensen & McNees, 1996; n = 15; Mean Years of Experience = 11.5)

  • Adequate ability to discriminate between partial and full-thickness NPUAP stage (r = 0.55)


Content Validity

Pressure Ulcers: (Bates-Jensen, 1992; n = 20; Chronic ulcers)

  • Items were selected based by a nine-member expert judge panel.
  • The content of validity index (0.91) and judges’ comments were used to modify two items on the PSST. Items were considered to be relevant and valid with a CVI of at least 0.78.

Pressure Ulcers (Karahan et al., 2014; Turkish sample)

  • Ten experts with experience in wound care evaluated BWAT items.
  • The content of validity index (0.82), based on agreement rate of expert ratings, led to revision of eight items. Items were declared appropriate and valid with a minimum item index of > 0.80.

Spinal Injuries

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Normative Data

Spinal Cord Injury: (Bates-Jensen et al., 2009; n = 24; Mean Age = 55.7 [31-77] years; Mean Time since SCI = 20.5; Mean Number of Ulcers = 1.21; Male veterans with spinal cord injury and recurrent pressure ulcers)

  • Mean Total Score = 33.63 (8.44)


Bates-Jensen, B. M. (1997). The Pressure Sore Status Tool a few thousand assessments later. Advances in Wound Care: The Journal for Prevention and Healing. 10(5): 65-73.

Bates-Jensen, B. M. (1998). “A quantitative analysis of wound characteristics as early predictors of healing in pressure sores.” Dissertation Abstracts International 59(11) Los Angeles, University of California.

Bates‐Jensen, B. M., McCreath, H. E., Harputlu, D., & Patlan, A. (2019). Reliability of the Bates‐Jensen wound assessment tool for pressure injury assessment: The pressure ulcer detection study. Wound Repair and Regeneration, 27(4), 386–395. doi: 10.1111/wrr.12714

Bates-Jensen, B., & McNees, P. (1995). Toward an intelligent wound assessment system. Ostomy/Wound Management, 41(7A Suppl), 80S-86S.


Bates-Jensen, B., & McNees, P. (1996). The Wound Intelligence System: Early issues and findings from multi-site tests. Ostomy/Wound Management, 42(10A Suppl), 53S-61S.


Bates-Jensen, B. M., & Sussman, C. (2012) “Tools to measure wound healing.” In C. Sussman and B. M. Bates-Jensen (Eds.), Wound Care: A Collaborative Practical Manual for Health Professionals (4th ed.). (131-172) Baltimore, MD: Lippincott, Williams & Wilkins.


Bates-Jensen, B. M., Vredevoe, D. L., & Brecht, M. L. (1992). Validity and reliability of the Pressure Sore Status Tool. Decubitus, 5(6), 20–28.

Gardner, S. E., Frantz, R. A., Bergquist, S., and Shin, Chingwei, D. (2005). A prospective study of the Pressure Ulcer Scale for Healing (PUSH). Journals of Gerontology, Series A, 60(1), 93-97.

Houghton, P. E., Kincaid, C. B., Campbell, K. E., Woodbury, M. G., & Keast, D. H. (2000). Photographic Assessment of the Appearance of Chronic Pressure and Leg Ulcers. Ostomy/Wound Management 46(4):20-30.

Karahan, A, Kilicarslan-Toruner, E, Ceylan, A, Abbasoglu, A., Tekindal, A., & Buyukgonenc, L. (2014). Reliability and Validity of a Turkish Language Version of the Bates-Jensen Wound Assessment Tool. Wound, Ostomy and Continence Nurses Society. 41(4):340-344. doi:10.1097/WON.0000000000000036