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Frozen section

Cutting the frozen section


Author: Jessica Wallace (see Reviewers page)
Revised: 23 October 2011, last major update October 2011
Copyright: (c) 2011, PathologyOutlines.com, Inc.

Procedure
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1. Once the chuck is in position, there should be a manual or an automatic advance option to move the block close to the cutting blade


Tissue embedded within OCT

2. Fully face the tissue by using a trim setting on your cryostat; if you do not have this setting, then an advance button should be available, which should be pressed each time before one full revolution of the instrument's wheel

3. If wells are used to freeze the blocks, then the tissue should be on an even plane and the tissue will be faced faster

4. To polish the tissue, avoid advancing the cryostat or deselect the trim setting on the cryostat and turn 10-15 times

5. As you cut the tissue, anchor the tissue to prevent folding or curling; this can be done with an anti-roll bar (a plastic plate attached to cryostat) or by using a pre-cooled paintbrush with stiff bristles and a wide gripping surface

6. The brush should be held like a pen with your left hand at an angle

7. You can rest your fifth finger on the stage for stabilization

8. Cutting the brushes’ bristles at an angle can aid in the brush meeting the tissue flat over its length because you will hold it at an angle

 
Left: brush with angled tip; right: holding the brush

9. Turn the wheel with your right hand in a continuous motion without stopping; avoid speeding up or slowing down

10. Avoid stopping the wheel at the beginning of the section, slowly grabbing the tissue and then resuming wheel revolutions; this can cause artifacts such as variation in section thickness and tissue folding

11. Move the brush as the chuck moves towards the blade; your brush should move down in pace with the chuck


Riding the block: as the block descends toward the brush, the brush keeps pace with the block by gently resting on the bottom 2-3 mm of the block

12. You can rest your brush softly on the very bottom of your chuck avoiding tissue contact


Riding the block: as the block descends toward the brush, the brush keeps pace with the block by gently resting on the bottom 2-3 mm of the block

13. Pull the brush away easily as the chuck meets the blade

   
Catching the curl: as the block meets the blade and the section begins its curl, the brush leaves the block while catching the curling edge of the section. Then the brush jumps off the block with the curl.

14. The downward motion of the brush allows you to keep a continuous motion as you take your section


Pull over the blanket: the brush holding the curl pulls the section horizontally over the stage, like pulling the blanket over yourself, without pressing the tissue to the stage

15. A glass slide is gently laid upon the tissue section

       
Gently touch the section to the slide. Avoid stretching or folding the section by keeping a steady hand, and keep the transverse axis of the slide parallel to the section.

16. The tissue section should melt onto the slide

17. Prepared slides should immediately go into formal alcohol, 95% alcohol (methanol/ethanol) or formalin while awaiting the stain line; if you delay this step, drying artifact will occur

18. You can take a deeper level after approximately 20 turns (multiple levels may be needed for breast or prostate biopsies)

19. Optimal cutting thickness is 4-7 microns for sectioning and 20-40 microns for trimming

Videos
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Brush technique

Additional references
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Pathology Innovations, IHC World

End of Frozen section > Cutting the frozen


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

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