6th ESACP Congress, Heidelberg, April 7-11, 1999

A111
AN INTERNATIONALLY AVAILABLE EXPERT-SYSTEM ALLOWS A PERMANENT AND STANDARIZED CONTROL OF THE DNA-CYTOMETRY
Oberholzer M, Hubler M, Dellas A, Schultheiss E, Egloff V, Haroske G, Kunze D, Meyer W

Department of Pathology, University of Basel, Basel, Switzerland

Background: The ESACP has agreed recommendations for correctly applying DNA-cytometry. Within research project EUROPATH a special program was developed allowing an automatical control of individual measurements according to these recommendations. This 'expert' is installed at the server EUROQUANT. It is always available via Internet. The aim of the study was to test the functionality of this 'expert-system' (ES), and to analyse its validity for the identification of methodical problems and the interpretation of DNA histograms. Method: Two key data of each nucleus measured by the CIRES system were presented to the ES: the integrated optical density (IOD) and the area (A). From these data the ES creates in a few seconds information allowing (1) a critical analysis of the homogeneity of the specimen measured, (2) an analysis of the settings of the optical components, (3) an objective description of the stem lines. The ES was tested on archival specimens from 44 patients with invasive cervical carcinoma. Those patients were also studied by comparative genomic hybridisation method (CGH). Results: The reference cell populations fulfilled the ESACP criteria. In 34 of the 44 cases 2 peaks were identifiable, in 8 cases 3 peaks, and in 2 cases 4 peaks. In 2 cases the glare correction in the collective of nuclei belonging to the first peak was outside of the ESACP limits; in 13 cases it was the case for the collective of the second peak. The coefficient of variation (CV) of the first peak was > 9% in 14 cases, the CV of the second peak and third peak in 3 cases each. Conclusions: (1) The ES can simply be used by routine in the cytological diagnostic. For it some organisational key elements must be defined. (2) Each measurement can automatically be tested by standardized and scientifically based methods. (3) The ES gives important information for an adequate interpretation of the histograms.