Knowledge Base › Troubleshooting Atlas › IHC
IHC weak / faint staining
Also known as: pale IHC, low intensity
What it looks like
Specific staining is present but too faint to interpret confidently.
Where it usually appears: Sub-optimal retrieval, dilute antibody, or short incubation.
Likely causes
- Antigen retrieval too gentle for the target
- Primary antibody over-diluted or incubation too short
- Detection system degraded
- Section too thin
Immediate checks
- Optimise retrieval (time/temperature/pH)
- Increase antibody concentration or incubation time
- Check detection reagents are in date
Corrective action
- Repeat with optimised protocol and a positive control
Preventive action
- Validate protocol per antibody
- Maintain reagent stock rotation
- Cut consistent section thickness
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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