Tissue fixation

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Tissue fixation, usually just fixation, is an important part of tissue preparation for histologic examination. It is typically done with formalin.

Implications

Pathologist have a great lifestyle 'cause tissue takes long to fix; the penetration of tissue by formalin is 1 mm/hour.[1]

Ratio

The dictum is:[2]

  • The volume of fixative should be 10x the volume of specimen.

Tissue fixation

A list of fixatives:[3]

Fixative Comment
Formalin, neutral buffered standard fixative
Formalin, unbuffered  ???
Glutaraldehyde[4] electron microscopy
Ethanol cytopathology
Carnoy  ???
Bouin toxic ???
B5 used for lymphoma, superior morphology - but toxic,
not good for IHC & DNA analysis[5]
IBF fixative used bone marrow and lymphatic tissue;[6] gives better nuclear detail in prostate biopsies compared to formalin[7]

Tissue fixation

Formalin

  • May be written (incorrectly) as "formulin".
  • Formaldehyde + methanol.

Fixing marking dye

To fix marking dye:

  • Formal-acetic alcohol (FAA):[8]
  • Bouin's solution.

Formal-acetic-alcohol

General:

  • Different recipes exist.

One recipe:[9]

  • Ethanol.
  • Acetic acid.
  • Formaldehyde.
  • Methanol.

See also

References

  1. Gross rounds. 14 August 2009.
  2. URL: http://www.cap.org/apps/docs/committees/cancer/cancer_protocols/2011/UvealMelanom_11protocol.pdf. Accessed on: 27 March 2012.
  3. Hunt, JL. (Feb 2008). "Molecular pathology in anatomic pathology practice: a review of basic principles.". Arch Pathol Lab Med 132 (2): 248-60. doi:10.1043/1543-2165(2008)132[248:MPIAPP]2.0.CO;2. PMID 18251585. http://www.archivesofpathology.org/doi/pdf/10.1043/1543-2165%282008%29132%5B248%3AMPIAPP%5D2.0.CO%3B2.
  4. Prentø, P. (Nov 1995). "Glutaraldehyde for electron microscopy: a practical investigation of commercial glutaraldehydes and glutaraldehyde-storage conditions.". Histochem J 27 (11): 906-13. PMID 8787969.
  5. Bonds, LA.; Barnes, P.; Foucar, K.; Sever, CE. (Aug 2005). "Acetic acid-zinc-formalin: a safe alternative to B-5 fixative.". Am J Clin Pathol 124 (2): 205-11. doi:10.1309/29DA-CY9K-BHNW-4BG6. PMID 16040290.
  6. URL: http://www.leicabiosystems.com/specimen-preparation/consumables/reagents-solutions/fixatives/details/product/ibf-tissue-fixative-1/. Accessed on: 26 September 2014.
  7. Trpkov, K.; Renault, P.; Yilmaz, A.; Ali-Ridha, N. (Jan 2006). "IBF as a formalin substitute fixative in prostate biopsy pathology.". Arch Pathol Lab Med 130 (1): 13-4. doi:10.1043/1543-2165(2006)130[13b:IAAFSF]2.0.CO;2. PMID 16390230.
  8. URL: http://www.brunelmicroscopes.co.uk/acatalog/Solvents___Reagents.html. Accessed on: 5 January 2011.
  9. URL: https://fscimage.fishersci.com/msds/45357.htm. Accessed on: 5 January 2011.

External links