GeoMx DSP Sample Prep Guidelines

When preparing, sectioning, and storing FFPE blocks for use in the GeoMx DSP instrument Protein and RNA assays, care should be taken to preserve sample integrity in all steps. The integrity of FFPE samples can be impacted by many factors, including time from excision to fixation, storage conditions, tissue type, and sample age. It is important to take such factors into consideration when selecting samples for the GeoMx DSP assay. Samples with poor integrity are likely to give low signal, particularly in the RNA DSP assay.

GeoMx has been validated for samples up to 3 years old prepared from tissues with a cold ischemic time of less than 1 hour using 10% NBF or similar fixative. We have also tested older sample blocks. In general for best results, do not use FFPE blocks greater than 10 years old. Assay performance, particularly for RNA, will be influenced by tissue block age and treatment conditions such as cold/warm ischemic time, fixative, and storage.