Knowledge Base › Troubleshooting Atlas › Tissue processing
Incomplete processing (soft, wet tissue centre)
Also known as: under-processed tissue, mushy centre
What it looks like
The block edges cut but the centre is soft, wet, or grey/translucent; sections tear in the middle.
Where it usually appears: Thick specimens, fatty tissue, exhausted reagents, or a short schedule.
Likely causes
- Specimen too thick for the schedule
- Exhausted / diluted dehydrating or clearing reagents
- Water carry-over reducing dehydration
- Fatty tissue needing longer clearing
Immediate checks
- Confirm specimen thickness (thin grossing helps)
- Check reagent rotation and change overdue stations
- Reprocess the affected block
Corrective action
- Reprocess through fresh reagents (dedicated re-processing schedule)
- Regross thick specimens thinner where possible
Preventive action
- Gross to an appropriate thickness (commonly 3–4 mm)
- Follow reagent change schedules and monitor quality
- Use a longer schedule for fatty/dense tissue
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 →