Knowledge Base › Troubleshooting Atlas › Floatation & mounting
Bubbles under the coverslip
Also known as: air bubbles, trapped air
What it looks like
Bubbles appear as clear or white circular areas under the coverslip, disrupting the view of the specimen.
Where it usually appears: Typically seen during the mounting process after applying the coverslip.
Likely causes
- Improper technique while placing the coverslip
- Inadequate drying of the slide or specimen
- Presence of dust or debris on the slide
- Rapid application of coverslip causing air entrapment
Immediate checks
- Inspect the slide for visible dust or debris
- Check if the mounting medium is too viscous
- Ensure the specimen is adequately dried
Corrective action
- Gently lift and reapply the coverslip using a proper technique
- Use a fine needle to remove trapped air bubbles
- Re-mount the slide if necessary
Preventive action
- Ensure thorough drying of the specimen before coverslipping
- Use a consistent and gentle technique when placing coverslips
- Minimize handling of the slide to prevent dust accumulation
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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