Purpose of Embedding
- Removes water and replaces it with paraffin wax
- Occurs after tissues have been processed
- Facilitates microtomy + long-term storage of tissue blocks
Processing provides __ support to tissues, whereas embedding provides __ support
Processing provides internal support to tissues, whereas embedding provides external support
List equipment used in embedding tissues
- Molten wax dispenser
- Hot surface
- Cold surface
- Metal molds
- (Warm) Forceps
Once the tissue is suspended in wax and placed on a cold surface…
WORK QUICKLY to press all edges of tissue to bottom EVENLY
Most tissues are embedded at a…
Slight angle, “cut side down”
What 2 indicators suggest follow-up action ?
- Tissue with soft consistency/ feels greasy (excluding fatty tissue)
- Tissue smells like xylene/ alcohol
Why might a block need to be re-embedded ?
- Tissue is crammed into a casette
- Mold used is too small
- Tissue not evenly pressed against mold and casette
- Air bubble within paraffin
What happens if mold is too small for the tissue ?
- Choose a different mold
- Difficulty in microtomy
Once the mold is initially filled halfway with paraffin, place the mold on a __ surface
Once the mold is initially filled halfway with paraffin, place the mold on a cold surface
When embedding, rotate between __ forceps
When embedding, rotate between warm forceps
What happens after the mold has been placed on the cold plate ?
As soon as the wax starts to turn white, WORK QUICKLY to press all edges of tissue EVENLY to the bottom
What do you do after pressing the tissue firmly on the cold surface ?
WITHOUT PUTTING THE MOLD BACK DOWN, fill it to the top with paraffin
BEFORE ALL OF THE WAX SOLIDIFIES, what needs to be done ?
The original tissue cassette must be pressed EVENLY on top of the mold
Multiple specimens in one block should…
Multiple specimens in one block should NOT TOUCH EACH OTHER
How is a block re-embedded ?
- The block is placed on a warming tray to soften and remove the paraffin
- Tissue is re-embedded
