Question: How can I more easily visualize the fiducial frame on Xenium slides?
Answer: Tissue sections are placed within the Sample Area on Xenium slides. Avoid covering the fiducials with tissue as this risks failures to initiate Xenium Analyzer run.
To more easily visualize the Fiducial Frame, and gain familiarity in targeting the sample area during tissue section placement, practice sectioning on a blank slide. Draw a frame to represent the Xenium fiducial frame on a blank slide using the Xenium Slide Layout in the Tissue Preparation Guides. Example slide layout (not to scale):
Practice correct section placement within the representative frames using non-experimental blocks.
- Xenium In Situ for Fresh Frozen Tissues – Tissue Preparation Guide
- Xenium In Situ for FFPE Tissues – Tissue Preparation Guide
If visualization is necessary during sectioning on Xenium slides, trace the fiducial frame on the back of the Xenium Slide with a StatMark Pen (EMS, 72109-12). Ensure the Xenium slide label is not readable during tracing. Remove the ink with a 100% ethanol-soaked, lint-free laboratory wipe as indicated in Demonstrated protocols:
- Demonstrated protocol: FFPE Deparaffinization and Decrosslinking (Prior to Deparaffinization)
- Demonstrated protocol: FF Fixation and Permeabilization (Prior to Permeabilization)
- Caution: Ensure the ink is completely removed and avoid touching the top of the slide where tissue is during the above steps. Residual ink persisting in the workflow may compromise assay performance.
Products: Xenium In Situ Gene Expression