Quality improvement in molecular pathology laboratories: providing the means for process management and standardization of pre-analytical handling of small biopsies.

The introduction of biomarker testing in cancer diagnosis has enabled a more personalized approach to the clinical management of these diseases. However, these tests require a closer monitoring of the total test process in order to avoid non-conformities. The pre-analytical phase in specific brings along challenges that can influence the analytical outcomes. Particularly with the use of high-throughput methods for molecular biomarker analysis, the management of these challenges is crucial. Molecular analysis requires a high sample quality and quantity. However, tumor biopsies are often small, which emphasizes that sample size preservation is crucial. By examining process flows in Belgian pathology laboratories, we can gain an overview of how small specimens are handled. Subsequently, recommendations on optimal sample handling and testing strategies can be formulated using a Delphi study. Furthermore, one of the sample requirements is a sufficient neoplastic cell percentage (NCP) in tumor tissue. However, there is a large variation in the estimation of this percentage. Harmonizing practices of tumor zone demarcation and NCP estimation in small biopsies with consensus-based guidelines will allow a similar interpretation by all the involved parties. Thus, by providing support in standardizing processing and preparation of these small biopsies, sample depletion and repeat biopsies can be prevented and accurate test results will be achieved, leading to improved patient safety.