frozen sections

Question 1

frozen section uses

Answer 1

rapid diagnosis

substance removed by processing ( fat )
enzymes studies ( muscle biopsy )
immunofluorescence or lymphocyte markers

Question 2

cryostat sections

Answer 2

cut at -20
warmer for water - avoid shatter & chatter
colder for fat - avoid rolling up sections

pathologist dissects specimen

sample placed on chuck with OCT compound

freeze, cut ( no ribbon will form )

read & report within 15-20 mins

Question 3

best quality sections

Answer 3

best quality sections are produced unfixed

slow freezing causes artifacts

Question 4

freezing

Answer 4

freezing can be faster
liquid nitrogen - 190
isopentane -150
aerosol spray -50

if specimens frozen attach lower temps extra time must be allowed before cutting or specimen may shatter

Question 5

bone

Answer 5

reasonable sections of bone can obtain without decal if the bone is spongy

useful for diagnosis of bone tumors

Question 6

anti roll plate

Answer 6

stops natural tendency of section to curl

if not exactly positioned will crumble
- some skip this step & use brush technique

Question 7

rate of cutting

Answer 7

slow for soft

hard & fast

Question 8

ice crystal artifacts

Answer 8

fast freezing is best

once incorrectly frozen cannot correct artifact

prevent by

• using a heat extractor
• freezing with isopentane
• use other rapid freezing methods
• ensure tissue isn’t immersed in saline prior to freezing

Question 9

block loosens from chuck while sectioning

Answer 9

reattach to clean chuck with addition embedding medium

avoid storing chucks without embedding medium in cryostat

don’t store blocks in cryostat overnight; defrost cycle occurs each evening

Question 10

tissue not embedded flat on chuck

Answer 10

place tissue onside surround with embedding medium then place the slide ( tissue up) on a freezing bar of cryostat
as medium turns white, coat a specimen chuck with embedding medium & invert one the tissue allow to freeze & remove slide by warming slightly with finger