Knowledge Base › Troubleshooting Atlas › Tissue processing
Greasy blocks from residual clearant
Also known as: greasy artifacts, block contamination
The tissue blocks appear shiny or oily, and sections may show poor staining quality. This can lead to obscured cellular details on slides.
Where it usually appears: Typically observed during routine histological processing, especially after clearing steps in paraffin embedding.
- Inadequate removal of clearing agent
- Excessive clearing agent used
- Improper embedding temperature
- Insufficient infiltration time
- Check for residual clearing agent in the embedding mold
- Inspect the embedding medium for correct viscosity
- Re-embed the tissue blocks using proper clearing agent removal techniques
- Adjust clearing agent concentrations used in processing
- Ensure thorough dehydration and clearing steps
- Monitor embedding temperatures and times closely
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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