Fixation

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Author: Mikael Häggström [notes 1]

General notes edit

Within an hour after removal from the body,[1] tissue samples should generally be placed in vessels with the correct fixing solution, with a volume that allows them to lie freely in the solution.[2] The standard fixation fluid is generally 10% neutral buffered formalin, which is roughly equivalent to 4% formaldehyde.[3]

The main exception to using formalin are mainly:

  • A tophus or other specimen suspicious for gout versus pseudogout should be sent in alcohol or dry, since formalin will dissolve the crystals.
  • Lymph nodes (or other lymphoid aggregates) with a suspicion of lymphoma, where samples are generally put in a special solution for flow cytometry.
  • Products of conception with a need to take samples for genetic testing.

Notes

  1. For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.

Main page

References

  1. . Breast pathology grossing guidelines. UCLA Health. Retrieved on 2021-09-09.
  2. Katarzyna Lundmark, Krynitz, Ismini Vassilaki, Lena Mölne, Annika Ternesten Bratel. Handläggning av hudprover – provtagningsanvisningar, utskärningsprinciper och snittning (Handling of skin samples - Instructions for sampling, cutting and incision. KVAST (Swedish Society of Pathology). Retrieved on 2019-09-09.
  3. . Paraformaldehyde, Formadehyde and Formalin. Duke University. Retrieved on 2019-12-17.