Notes on Section Cutting Faults

Faults Observed During Section Cutting

General Observations

  • During section cutting, various faults may occur that lead to issues with the quality of tissue sections.

Common Faults and Causes

Sections Expand or Disintegrate
  • Causes:
    • Poor impregnation of tissue
    • Water temperature too high in flotation bath
  • Remedies:
    • Re-process tissue
    • Lower temperature of flotation bath
Sections Roll into a Coil
  • Causes:
    • Dull blade
    • Small rake angle
  • Remedies:
    • Use a new blade
    • Adjust rake angle to an appropriate setting
Grooved or Scored Sections
  • Causes:
    • Section thickness too great
    • Dull knife/blade edge
  • Remedies:
    • Reduce section thickness
    • Re-sharpen knife or replace blade
Sections Fail to Form Ribbons
  • Causes:
    • Too warm room temperature
    • Non-parallel surfaces of the block
  • Remedies:
    • Cool the room or tissue block with ice water
    • Re-trim the block and ensure surfaces are parallel
Problems with Ribbon Thickness and Quality
  • Issues:
    • Ribbons may curl, be uneven, or break
  • Causes:
    • Knife dullness
    • Knife tilt too great
  • Remedies:
    • Sharpen the knife
    • Clean knife edge
    • Reduce knife tilt

Additional Specific Faults

Compressed Sections
  • Causes:
    • Blunt knife
    • Soft paraffin block
    • Incorrect knife tilt
    • Rapid cutting
  • Remedies:
    • Re-sharpen knife
    • Cool the block before sectioning
    • Adjust cutting speed
Unequal Thickness of Sections
  • Causes:
    • Incorrect knife angle or tilt
    • Hard spots in tissue
  • Remedies:
    • Re-adjust knife angle and tilt
    • Decalcify hard tissue if necessary

Tissue Processing Faults

Clearing Agent Problems
  • Issues:
    • Clearing agent turns milky or has a strong odor
  • Causes:
    • Prolonged fixation, dehydration, or clearing
    • Incomplete removal of alcohol
  • Remedies:
    • Repeat dehydration with absolute alcohol
    • Adjust clearing time and methods
Soft or Mushy Tissue
  • Causes:
    • Inadequate clearing or dehydration
  • Remedies:
    • Repeat processes ensuring thorough cleaning
Brittle or Hard Tissues
  • Causes:
    • Prolonged fixation or dehydration processes
    • Calcareous hard spots in tissues
  • Remedies:
    • Treat with appropriate solutions to soften
    • Ensure routines are adjusted for fat processing

Key Reminders for Section Cutting

  • Always ensure knife is sharp
  • Monitor room temperature for optimal cutting conditions
  • Regularly re-check the parallelism of the block and knife angles