Knowledge Base › Troubleshooting Atlas › Quality & QC
Control tissue giving inconsistent results
What it looks like
Control tissue may show uneven staining or no staining in critical areas.
Where it usually appears: Typically appears during routine quality control checks or when running batches of samples.
Likely causes
- Inadequate fixation of control tissue
- Improper storage conditions
- Expired or degraded reagents
- Inconsistent section thickness
- Contamination during processing
Immediate checks
- Verify fixation time and method used
- Check storage conditions of control tissue
- Inspect reagent expiration dates
Corrective action
- Re-fix control tissue if inadequate fixation is suspected
- Replace expired reagents
- Re-run the staining protocol with fresh reagents
Preventive action
- Establish a regular schedule for reagent checks
- Implement proper storage protocols for control tissues
- Train staff on consistent sectioning 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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