PROBLEM-REASON-REMEDY

Cards (56)

  • Brittle or hard tissue
    REASON:
    • Prolonged fixation, dehydration, clearing, paraffin infiltration
    • Overheated paraffin oven
    • Drying out of tissue before actual fixation
  • Brittle or hard tissue
    REMEDY:
    • Softened by soaking in a small dish or bowl containing water with detergent, phenol or Molliflex
  • Clearing agent turns milky as soon as tissue is placed in it
    REASON:
    • Water not completely removed
    • Incomplete dehydration
  • Clearing agent turns milky as soon as tissue is placed in it
    REMEDY:
    • Repeat dehydration with absolute alcohol
    • Clear again
  • On trimming, tissue smells of clearing agent
    REASON:
    • Clearing agent not completely removed
    • Insufficient impregnation
  • On trimming, tissue smells of clearing agent
    REMEDY:
    • Block is trimmed down nearest to the tissue
    • Remaining wax is melted on embedding oven
    • Paraffin impregnation is repeated
    • Change paraffin at least once before blocking
  • Tissue is opaque, section cutting is difficult due to presence of alcohol
    REASON:
    • Insufficient clearing
  • Tissue is opaque, section cutting is difficult due to presence of alcohol
    REMEDY:
    • Repeat clearing
    • If object has already been embedded, prolong clearing up to 12 hours, then re-embed
  • Tissue shrinks away from wax when trimmed
    REASON:
    • Insufficient dehydration
    • Incomplete clearing and impregnation
  • Tissue shrinks away from wax when trimmed
    REMEDY:
    • Repeat whole procedure
  • Tissue is soft when block is trimmed
    REASON:
    • Incomplete fixation
  • Tissue is soft when block is trimmed
    REMEDY:
    • Repeat whole procedure
  • Air holes found on tissue during trimming
    REASON:
    • Incomplete impregnation
  • Air holes found on tissue during trimming
    REMEDY:
    • Repeat impregnation
  • On trimming, wax appears crystalline
    REASON:
    • Contaminated wax
    • Block not cooled rapidly enough
  • On trimming, wax appears crystalline
    REMEDY:
    • Re-embed in freshly filtered wax
  • Paraffin block, after cooling, is moist and crumbles
    REASON:
    • Insufficient paraffin impregnation
  • Paraffin block, after cooling, is moist and crumbles
    REMEDY:
    • Repeat paraffin impregnation, then re-embed
  • Sections fail to form ribbons
    REASON:
    • Surfaces and edges of the block are not parallel
    REMEDY:
    • Re-trim the block
  • Sections fail to form ribbons
    REASON:
    • Horizontal surface of the block is not parallel to the knife
    REMEDY:
    • Re-adjust and re-orient the block
  • Sections fail to form ribbons
    REASON:
    • Paraffin wax is too hard
    REMEDY:
    • Coat horizontal edges of the block with wax of lower melting point
  • Sections fail to form ribbons
    REASON:
    • Knife is tilted too much
    REMEDY:
    • Reduce tilt
  • Sections fail to form ribbons
    REASON:
    • Sections are too thick
    REMEDY:
    • Re-adjust the thickness of the sections
  • Sections fail to form ribbons
    REASON:
    • Knife is dull
    REMEDY:
    • Hone and strop
  • Sections roll up on cutting so that they adhere and get broken against the knife edge
    REASON:
    • Knife is blunt
    REMEDY:
    • Sharpen the knife
  • Sections roll up on cutting so that they adhere and get broken against the knife edge
    REASON:
    • Tilt of knife is too great
    REMEDY:
    • Reduce the tilt
  • Sections roll up on cutting so that they adhere and get broken against the knife edge
    REASON:
    • Knife edge is dirty
    REMEDY:
    • Clean the knife edge
  • Ribbon is curved, crooked or uneven instead of straight
    REASON:
    • Blunt of dull spot on the knife = irregular knife edge
    REMEDY:
    • Adjust the knife so that knife edge will present a uniformly sharp edge to the block
    • Sharpen
  • Ribbon is curved, crooked or uneven instead of straight
    REASON:
    • Edges of the block are not parallel but round or wedge shape
    REMEDY:
    • Re-trim the block
  • Ribbon is curved, crooked or uneven instead of straight
    REASON:
    • Knife is not parallel to the block
    REMEDY:
    • Readjust knife and block
  • Ribbon is curved, crooked or uneven instead of straight
    REASON:
    • Paraffin is impure
    REMEDY:
    • Repeat impregnation using pure wax
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Knife is blunt or dull
    REMEDY:
    • Re-sharpen the knife
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Paraffin block is warm and soft
    REMEDY:
    • Cool the block on ice water until firm
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Knife edge is coated with paraffin
    REMEDY:
    • Clean the knife edge
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Sections are too thin
    REMEDY:
    • Readjust thickness of section
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Microtome set screw is loose
    REMEDY:
    • Tighten the screw
  • Sections are compressed, wrinkled, or jammed
    REASON:
    • Tilt of knife is too vertical
    REMEDY:
    • Reduce the tilt
  • Sections are squashed (width of each section is less than that of block)
    REASON:
    • Bevel of knife is lost due to incorrect sharpening
    REMEDY:
    • Re-sharpen, using a knife back or automatic knife sharpener
  • A hole is formed in the section
    REASON:
    • Bubble or dirt formed in the embedding medium
    REMEDY:
    • Re-embed in freshly filtered wax if necessary
  • A hole is formed in the section
    REASON:
    • Hard spot in tissue due to calcium
    REMEDY:
    • Once embedded in paraffin wax, decalcification is impractical; use a base-sledge microtome with a wedge knife