In answer to the letter of Ferrell & Osterweil, the technique described by Resch et al has been used in a very meticulous research study. It has been shown to be accurate and reproducible in a large series of patients, and has had absolutely no problem with safety. The technique has absolutely no value in shearing injuries. The authors of the paper have, on multiple occasions, tried to differentiate between shearing injuries which start at the surface, and true pressure sores which start at the underlying bony prominence. Only in the true pressure sore is volume determination a problem, and it has proved to be very useful in these situations. As mentioned in the article, determining the surface is quite difficult in a very cachectic patient. However, if one attempts to round off the contour of the mold to match the opposite side contour, it has proved very reproducible and useful. Using the mold serially allows one to compare the mold in a given pressure sore over a period of healing. Therefore, the contour is designed similarly on each measurement and has proved to be very reproducible among various raters. Regarding contamination, all pressure sores by definition have a tissue bacterial count. This has been very well shown in multiple publications from our group. When one has a chronic bacterial count within tissue, surface contamination does not add to it in any way. In the study which is reported, quantitative bacterial counts were recorded each time the measurement was done, and there was no increase in bacterial counts because of the measuring technique. The authors feel strongly that all pressure sores should be debrided of necrotic tissue before any treatment is begun. Therefore, all measurements were undertaken when necrotic debris had been removed. Another issue brought up by the authors of the letter has to do with “inflating’ the undermined skin. No pressure is used to place the material into the sore and therefore there is no possibility of expanding it during the measuring technique. The authors of this article have been involved in multiple clinical trials regarding the treatment of pressure sores. During these multiple trials, many techniques of volume measurement have been tried. We feel that the technique described in the May 1988 issue of the Journal is the best that we have worked with to date.