External quality assurance in histopathology: experience of the east of Scotland scheme.

AIMS To examine the overall organisation of a voluntary external quality assurance scheme in histopathology, selection of case material and marking systems; and to assess the scheme in relation to contemporary histopathological practice. METHODS Case material was derived from all participating departments and a positive marking system was used throughout the scheme. RESULTS The mean response rate by those agreeing to participate was 66% and remains stable. The mean score of each set (n = 8) was high (63-80%) but scores about the mean varied widely in each set. The positive marking system was satisfactory and provided information equivalent to negative and weighted marking systems. The use of local coordinators providing the link between the central organiser and individuals has spread the administrative load and facilitated the introduction of small biopsy specimens. The selection of suitable case material has proved difficult at times. CONCLUSIONS The scheme has an important role in histopathology quality assurance. It has been operative for four years and is widely accepted in the east of Scotland; it can be adapted to suit local circumstances.