Histology Laboratory

Histology Submission Instructions – Frozen Sections

One of the benefits of frozen tissue samples is the time saved by omitting the initial fixation step required for paraffin-embedded tissue, which avoids the possible requirement to retrieve epitopes masked by formaldehyde cross-linking. Frozen tissue is cut on a cryostat and sections can be stored at -80 °C for up to 1 year.

Disposable embedding mold
OCT medium
Aluminum foil
Freezing spray Liquid Nitrogen, or Dry Ice
Petri Dish
Kim wipes

1. Before you dissect the animal get one special container filled with liquid nitrogen and another container filled with some dry ice.

2. Label base mold and partially fill the mold with OCT.

3. Remove desired tissue and place in cold PBS and wash out the blood.

4. Transfer tissue to a clean Petri dish and use the Kim wipes to absorb the PBS on the tissue surface.

5. Place tissue in pre-labeled base molds filled with OCT. Try to arrange tissue flat in OCT near the bottom so tissue is easily exposed when sections are cut.

6. Use forceps to hold base mold edge and place the base mold into the surface of the liquid nitrogen and just let bottom of base mould to touch the surface of the nitrogen. Hold until the tissue solidifies (around 30 seconds). Note: If block is left in too long, it may crack.

7. Remove tissue from liquid nitrogen and place blocked tissue on dry ice. (Tissue may be kept in plastic container, plastic bags or wrapped in aluminum foil.)

8. Store frozen tissue block in -80°C freezer until sectioning.

9. Complete Pathology Research Resources submission form.

10. Transport samples to Pathology Research Resources Laboratory on dry ice.

11. Discuss your needs with the histotechnologist and/or provide a written protocol, providing:

  • Thickness of sections
  • Number of sections per slides
  • Number of slides per sample
  • Fixed or unfixed sections
  • Stained or unstained sections
  • Special instructions


The Investigator should contact the Lab to schedule a Frozen Section Service. At that time, arrangements can be made to immediately deliver the specimens for processing, if feasible. Alternatively, the specimens can be obtained and frozen for later processing.

Questions? Please visit our lab located at RSMB 7th floor, room 7128 or call us at 305-243-3824