QUALITY-CONTROL IN IMAGE CYTOMETRY - DNA-PLOIDY

DNA ploidy has become a commonly performed quantitative image cytometr y test in microscopic pathology. This has led to the need to develop q uality control procedures to aid in assuring uniform and reliable test results. There are a number of unique issues related to the emerging technology of image analysis and its routine use as a quantitative mic roscopic assay that require consideration before establishing;l qualit y control program. Previous considerations of this topic have primaril y related to measurement issues, e.g., accuracy comparisons to other m ethodologies, calibration of instrumentation, sources of measurement e rror, and the interpretation of measurement results. Although these is sues are critically important, with more routine usage the focus is no w turning to quality control of the overall testing process in everyda y use. Control charts and methods of controlling the total measurement process such as have been used in clinical chemistry, need to be esta blished. As one of the first image assays in pathology, quality contro l procedures established now for DNA ploidy measurements could help sh ape the development of this field, especially as pathology transitions from being a subjective visual microscopic inspection process to a qu antitative measurement process. This paper discusses these issues as t hey relate to overall quality assurance for the DNA ploidy test and de scribes a quality control program developed for an active breast cance r testing laboratory specializing in image cytometry tests, including DNA ploidy. The quality control program includes calibration control c harts, control charts for internal diploid controls, check samples, an d computerized individual histogram interpretation. (C) 1994 Wiley-Lis s, Inc.