Background: Clinical interpretation of laboratory results is an integral part of clinical chemistry. However, the performance goals for assessing interpretative commenting in this discipline have not been as well established as for the quality of analytical requirements.Methods: We present a review of the 10 case reports circulated in the 2002 Patient Report Comments Program by the Royal College of Pathologists of Australasia (RCPA) and the Australasian Association of Clinical Biochemists Chemical Pathology Group of RCPA-Quality Assurance Programs Pty Ltd. Participants were expected to add an interpretative comment to a set of results accompanied by brief clinical details. Comments received were broken down into components that were translated into key phrases. An expert panel evaluated the appropriateness of the key phrases and proposed a suggested composite comment. A case summary/rationale was also returned to participants.Results: There was considerable diversity in the range of interpretative comments received for each case report. Although the majority of comments received were felt to be acceptable by the expert panel, some comments were felt to be inappropriate, misleading, or in a few instances, dangerous.Conclusion: The golden rule in medicine is "do no harm". Although there is no objective evidence that interpretive comments help to improve patient outcomes, if comments are added to reports it is important that they reflect accepted practice and current guidelines. It is of concern that a large proportion of comments returned were considered to be inappropriate and/or misleading. The Patient Report Comments Program has highlighted the need to consider limiting commenting to persons with clear expertise. (C) 2004 American Association for Clinical Chemistry.