Knowledge Base › Troubleshooting Atlas › Tissue processing
Water / clearant carry-over into wax
Also known as: reagent contamination, cloudy wax
What it looks like
Cloudy or milky wax, poor infiltration, soft blocks and inconsistent sectioning.
Where it usually appears: Exhausted dehydration steps or infrequent reagent changes.
Likely causes
- Incomplete dehydration leaving water to carry forward
- Clearant carry-over diluting the wax
- Overdue reagent and wax changes
Immediate checks
- Check and change overdue alcohol/clearant stations
- Replace contaminated wax baths
- Confirm dehydration is complete before clearing
Corrective action
- Full reagent and wax change; reprocess affected tissue
- Audit the rotation schedule
Preventive action
- Strict reagent rotation and change schedule
- Monitor final alcohol and wax quality
- Keep a reagent-change log
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.
Unimeditrek supports histopathology laboratories with tissue processors, microtomes, staining and workflow equipment plus service and AMC. Talk to a specialist →