Specimen Preparation Guide for Clinical Use: FFPE
To ensure submitted specimens yield sufficient amounts of extracted DNA and/or RNA for sequencing and analysis, we have provided the following guidelines below for solid tumors. Unacceptable specimens include hematolymphoid malignancies or decalcified bone.
FFPE — Specimen Preparation
Guidelines for FFPE preparation:
- Fix tissue samples in 4–10% neutral buffered formalin as quickly as possible after surgical removal.
- Use a fixation time of 14–24 hours (longer fixation times may lead to more severe DNA fragmentation, resulting in poor performance in downstream assays).
- Thoroughly dehydrate samples prior to embedding (residual formalin can inhibit the proteinase K digest).
- FFPE sections should be as fresh as possible. Older FFPE sections may yield poorer results.
- For core biopsy, use 3–5 cores laid down so that when cut, the blade is running parallel to the long axis of the cores.
