Decalcification

1.12. When using specimens containing hard tissues, an EDTA decalcification should be performed (C); acid decalcification should be avoided (N). 6

Paraffin‐embedding

1.13. Conventional tissue processors (closed automated instruments) can be used while referring to general procedures (C). However, the influence of the reagents, processing protocol, and processor maintenance (e.g., the frequency of replacement) remains unknown. There are insufficient data on rapid‐type processors (continuous rapid automated instruments).

Storage of FFPE blocks

1.14. FFPE blocks can be stored at room temperature (C). However, the blocks should be stored in a cool, dark place (C) and not exposed to high humidity (N) (C). FFPE blocks for genomic testing may be stored under refrigeration (4°C) (R). 23

Storage of unstained FFPE slides

1.15. For the storage of unstained FFPE slides, preventive measures such as low‐temperature storage or coating with a thin‐layer paraffin should be undertaken to avoid deterioration of nucleic acid quality. However, in principle, long‐term storage of unstained FFPE slides for genomic testing should be avoided (N), and unstained FFPE slides should preferably be freshly prepared from the FFPE block, if possible (C).