Specimen Handling & Fixation Flashcards

When grossing a large colectomy specimen, the CORRECT initial step for proper fixation is:

Answer: Open along the antimesenteric border and pin flat before fixation

Opening the colon along the antimesenteric border and pinning it flat allows formalin to penetrate the mucosal surface and fixes the specimen evenly.

Which of the following is the BEST indicator that formalin fixation is complete in a tissue section?

Answer: Tissue is firm throughout with no soft or gelatinous areas

Complete fixation produces uniform firmness throughout the tissue; soft or gelatinous areas indicate that fixative has not fully penetrated the specimen.

Which special consideration applies when handling a testicular biopsy for fertility evaluation?

Answer: Submit entirely fresh for sperm analysis and fix a small portion in Bouin's

Fertility biopsies require fresh tissue for spermatogenesis analysis by the andrology lab, while a small portion is fixed (often in Bouin's) for histologic evaluation.

The MOST significant risk of prolonged over-fixation in formalin (>72 hours) is:

Answer: Excessive cross-linking that masks antigens and impairs IHC staining

Over-fixation creates excessive protein cross-links that can mask epitopes, reducing IHC sensitivity and requiring more aggressive antigen retrieval protocols.

A specimen labeled 'fresh frozen section ONLY' is accidentally placed in formalin. The FIRST action should be:

Answer: Notify the pathologist immediately before taking any further action

Any specimen handling error must be immediately reported to the pathologist so they can assess the impact on diagnosis and determine the appropriate next steps.

Which tissue component is LEAST well-preserved by standard 10% neutral buffered formalin?

Answer: Lipids

Formalin does not fix lipids, which are extracted during alcohol dehydration steps in processing, leaving empty spaces or requiring special fixatives like osmium tetroxide.

When handling a needle core biopsy of the prostate, the technician should:

Answer: Wrap cores in lens paper or place on a sponge before submitting in NBF

Tiny core biopsies are wrapped in lens paper or placed on sponges/HistoWraps to prevent loss, aid orientation, and ensure complete fixation before processing.