Part II: Specific Recommendations for Quality Assurance

Quality assurance in medical services has become a more and more important issue. In order to achieve reliable results of DNA image cytometry as described and discussed in detail in the first part of this report [2], the conditions for reproducible preparation, measurement and interpretation have to be worked out, carefully followed and checked at various steps of the process in certain time intervals. Herein Quality Assurance (QA) is meant as a continuous process in assuring the uniformity and reliability of the diagnostic outcome of the quantitation procedure. It works continuously in a logistic concept with feedback to the sample preparation, the instrumentation settings, the densitometric measurements, and the diagnostic interpretation. In this context Quality Control (QC) is aimed to retrieve the error sources at all stages of the entire methodological and diagnostic process. From our knowledge [1] we consider the following points to be the most important ones to achieve the desired uniformity and reproducibility of DNA-ICM assessment: specimen preparation, staining, instrumentation, sampling, densitometric measurements, scaling process and measurement interpretation. Beside sampling procedures all other topics have been conceived in form of quality control tests, presented in detail in the following. Setting “correct” sampling strategy is a prerequisite for reliable interpretation and the importance for this step lies in the fact that the consequences of sampling strategy cannot be corrected at a later stage.