Knowledge Base › Troubleshooting Atlas › IHC
Non-specific nuclear staining in IHC
What it looks like
Nuclear staining appears diffuse and non-specific, often overshadowing true target staining. Background may appear dark or hazy.
Where it usually appears: Typically observed in tissues with high background staining or when using certain antibodies.
Likely causes
- Inadequate blocking of non-specific binding sites
- Improper dilution of primary antibody
- Inappropriate incubation times or temperatures
- Cross-reactivity of antibodies
- Poor quality of reagents
Immediate checks
- Verify antibody dilution and expiration date
- Inspect blocking agent for effectiveness
- Check incubation conditions
Corrective action
- Optimize antibody dilution
- Increase blocking time or change blocking agent
- Adjust incubation temperature or duration
Preventive action
- Use well-characterized antibodies
- Perform pre-optimization tests for new antibodies
- Regularly validate and calibrate reagents
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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