Comparative analysis of two methods for wound bed area measurement.

Wound bed area measurements are considered to be an essential part of the wound assessment process. Wound care professionals should be aware of the reliability and validity of the techniques they use. The purpose of this study was to assess whether wound care professionals are able to make as accurate and reproducible a measurement of the wound bed area using two methods for area measurement. Five wound care professionals independently assessed 2285 digital wound images for the wound bed area. Each image was measured in random order, three times, and in four angles by providing the rotated versions of each image (0°, 90°, 180° and 270°). Two techniques were compared: free hand drawing and closed polygon (CP) graph algorithm. Comparison of the two techniques showed differences that are, in our opinion, not acceptable in clinical practice when these techniques are used interchangeably and/or the measurements are carried out by different observers. Variations observed between wounds and observers seem related to the difference in perception of the wound bed margin. Our results indicate that repetition of CP graph area measurement results in the lowest difference in repetitive measurements. Study limitations are related to an incomplete consensus on definitions of wound, wound bed, wound edge and wound border. The development of an ontology related to wound images could aid to reduce these ambiguities.