Knowledge Base › Troubleshooting Atlas › H&E staining
H&E too pink / weak haematoxylin (pale nuclei)
Also known as: weak nuclear staining, washed-out H&E
What it looks like
Nuclei are pale grey-blue and indistinct while the section looks overall pink; poor nuclear contrast.
Where it usually appears: Exhausted haematoxylin, over-differentiation, or acidic water.
Likely causes
- Exhausted or under-strength haematoxylin
- Over-differentiation in acid alcohol
- Insufficient bluing
- Acidic tap/rinse water
- Over-fixation or acid decalcification masking nuclear staining
Immediate checks
- Extend haematoxylin time or replace the reagent
- Reduce differentiation time
- Ensure an adequate bluing step in alkaline water
Corrective action
- Re-stain with fresh haematoxylin
- Check and buffer rinse water if acidic
Preventive action
- Replace/filter haematoxylin on schedule
- Run daily controls
- Limit acid decalcification time; use buffered fixative
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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