Unimeditrek SOP template — save it as PDF or print.
UNIMEDITREKTOTAL MEDICAL SOLUTIONS
SOP TEMPLATE Doc ref: UMT/SOP/TISSUE-EMBEDDING Reviewed: July 2026 Rev.: template
Tissue Embedding SOP
Histopathology · Unimeditrek Pvt. Ltd.
⚠️ Validation required. This SOP template is provided for educational and quality-system support only. It is a starting point to adapt — not a validated procedure. Each laboratory must review, complete the lab-specific fields, validate and approve this SOP through its own pathologist / quality manager, and align it with local regulatory requirements before use.
1. Purpose
To cast firm, correctly-oriented paraffin blocks that section cleanly, presenting the diagnostically relevant tissue plane.
2. Scope
Applies to paraffin embedding of processed tissue at the embedding station. Excludes processing and microtomy.
3. Responsibility
Histotechnician — embeds tissue with correct orientation and casts blocks.
Senior technician — checks orientation and block quality; trains new staff.
Pathologist / quality manager — approves this SOP and reviews re-embedding rates.
4. Equipment & materials
Tissue embedding station (heated reservoir, cold plate, forceps warmer)
Molten paraffin and heated surfaces cause burns — use warmed forceps and care.
Maintain ventilation; follow PPE and waste rules.
6. Procedure
Setup
Confirm reservoir and cold-plate are at working temperature. Reservoir: [lab to validate]; cold plate: [lab to validate].
Keep processed cassettes warm until embedded to prevent premature setting.
Embed
Select the correct orientation for the tissue type (e.g. tubular/layered tissue on-edge to show all layers).
Dispense molten paraffin into the mould, position tissue with warmed forceps, then transfer to the cold plate to set the orientation before topping up.
Add the labelled cassette as the block base and top up with paraffin; allow to cool fully before removing.
7. Quality-control checkpoints
Correct orientation for the tissue type; full-face sections achievable.
No air bubbles or voids; block firm with tissue flat and complete.
8. Acceptance criteria
Blocks section on the first face without re-embedding; orientation matches the grossing intent.
9. Common errors & corrective action
Problem
Corrective action
Wrong orientation
Re-embed on the correct plane; mark orientation at grossing; use an orientation reference at the station.
Air bubbles / voids in the block
Embed with fully molten paraffin at the correct temperature; pour gently to avoid trapping air.
Tissue not flat / shifts before setting
Allow the cold plate to set orientation before moving; verify cold-module temperature.
10. Records & documentation
Embedding register / re-embedding log
Corrective-action record
11. Review frequency
Review at least annually or after a workflow/equipment change or recurring re-embedding.