Microtomy SOP

Histopathology · Unimeditrek Pvt. Ltd.

⚠️ Validation required. This SOP template is provided for educational and quality-system support only. It is a starting point to adapt — not a validated procedure. Each laboratory must review, complete the lab-specific fields, validate and approve this SOP through its own pathologist / quality manager, and align it with local regulatory requirements before use.

1. Purpose

To produce thin, complete, wrinkle-free sections that adhere to the slide and stain evenly, safely and reproducibly.

2. Scope

Applies to paraffin section microtomy on a rotary microtome, including floatation and slide pickup. Excludes cryostat/frozen sectioning.

3. Responsibility

Histotechnician — sections blocks, mounts and dries slides, records issues.
Senior technician — maintains blades/microtome, checks section quality.
Pathologist / quality manager — approves this SOP and reviews recut rates.

4. Equipment & materials

Rotary microtome, fresh microtome blades, cold plate/ice for chilling blocks
Temperature-controlled floatation (water) bath, adhesive/charged slides, slide warmer/drier

5. Safety precautions

Microtome blades are extremely sharp — engage the blade guard and lock the handwheel when not cutting.
Handle blades with a blade dispenser; never wipe toward the edge.

6. Procedure

Prepare

Chill the block on a cold plate/ice before cutting to improve section quality.
Insert a fresh blade edge; set the correct clearance angle for the blade type; confirm block and knife clamps are tight.

Section

Trim to expose full tissue, then cut ribbons at the set thickness. Section thickness: [lab to validate] (commonly a few microns for routine H&E).
Float sections on the warm bath to relax and flatten. Bath temperature: [lab to validate] (just below the paraffin melting point).
Pick sections up on adhesive/charged slides (for fatty/calcified/bloody tissue) and drain.

Dry

Dry/warm slides adequately before staining to secure adhesion. Drying: [lab to validate].

7. Quality-control checkpoints

Complete, flat sections without chatter, folds, tears or compression.
Sections adhere through staining without lifting; even thickness.

8. Acceptance criteria

Sections mount and stain without recuts; no recurring mechanical defects.

9. Common errors & corrective action

Problem	Corrective action
Chatter (thick–thin bands)	Check for over-hard block, dull blade, loose clamps or wrong clearance angle; cool the block; review processing.
Compression / crowding	Chill the block; use a fresh blade edge; slow the cutting stroke.
Wrinkles / folds after floatation	Set the bath just below paraffin melting point; fix upstream compression.
Tissue lifts off during staining	Use adhesive/charged slides; increase drying/warming time.

10. Records & documentation

Microtomy / recut log
Blade-change and microtome-service record

11. Review frequency

Review at least annually or after equipment service or a recurring defect.

12. Approval

Role	Name	Signature	Date
Prepared by
Reviewed by (Quality Manager)
Approved by (Pathologist)

Unimeditrek Pvt. Ltd. — histopathology laboratory equipment manufacturer, India. Author: Unimeditrek Technical Content Team · Reviewed by: Biomedical Engineering & Histopathology Applications team · Last reviewed: July 2026.
📞 +91-98105 33445 · sales@unimeditrek.com · www.unilabequipments.com · Manufactured under ISO 9001 & ISO 13485 QMS; certificates on request.
© Unimeditrek Pvt. Ltd. This is an adaptable template for laboratory use — complete the highlighted fields and validate through your own quality system before implementation.