Knowledge Base › Troubleshooting Atlas › Embedding
Incomplete filling of the mould
What it looks like
The block shows areas of incomplete tissue encapsulation, leading to weak structural integrity. This may result in sections that crumble or detach during cutting.
Where it usually appears: Typically observed during the embedding step when the tissue is not fully surrounded by paraffin.
Likely causes
- Insufficient paraffin temperature
- Inadequate vacuum during embedding
- Improper orientation of the tissue
- Too rapid cooling of the embedding mould
- Low quality of paraffin used
Immediate checks
- Check paraffin temperature
- Inspect vacuum pump operation
- Review tissue orientation in the mould
Corrective action
- Re-embed the tissue with proper paraffin temperature
- Ensure adequate vacuum is applied during embedding
- Adjust the cooling rate of the embedding mould
Preventive action
- Regularly calibrate embedding equipment
- Use high-quality paraffin
- Train staff on proper embedding techniques
This atlas is for educational purposes for laboratory professionals. It does not replace your institutional SOPs, manufacturer instructions, validated protocols or pathologist judgment. Adapt any action to your laboratory and equipment.
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