frozen section and decalcification

Question 1

what is the CAP accreditation standard time for frozen section

Answer 1

20 mins

Question 2

4 application for frozen section

Answer 2

Intra-operative consultations
Enzyme histochemistry
Immunofluorescent techniques
Lipid stains

Question 3

benefits for enzymes in frozen sections

Answer 3

Enzymes are labile and rapidly degrade when removed from blood and fixed

Freezing tissue = best to preserve enzymes (especially in muscles)

Question 4

benefits from immunofluorescnt techniques in frozen sections

Answer 4

Fixation will degrade Ab

Aldehyde fixatives create autofluorescence

Question 5

benefits from lipid stains in frozen sections

Answer 5

Fixations will dissolve lipids

Neutral lipids (fat) can be visualized

Question 6

what is freezing artifact

Answer 6

ice crystals in muscle that leaves holes in tissue

Question 7

how to minimize freezing artifact

Answer 7

freeze rapidly using heat extractors, dry ice, or liquid nitrogen

Question 8

what temp for sectioning at -7C to -13C

Answer 8

brain
liver
thyroid

Question 9

what temp for sectioning at -13 to -16C

Answer 9

skin
liver
muscle

Question 10

what temp for sectioning at -20 to -30C

Answer 10

breast
fatty tissue

Question 11

what is used to freeze tissue in place

Answer 11

FSC

Question 12

T/F frozen sections form ribbons

Answer 12

F

Question 13

when tissue is on slide, what is used to fix

Answer 13

formalin or alcohol before staining with H&E

Question 14

how is quality assurance demonstrated in frozen sectioning

Answer 14

comparison of frozen slide and paraffin slide to confirm

Question 15

cause and resolution of chatter

Answer 15

Block being too cold or loose component

All levers tight and increase temperature of cryostat / warm block

Question 16

cause and resolution of shattering

Answer 16

Cryostat is too cold (seen most in lymph nodes)

Increase temperature or heat from gloves

Question 17

cause and resolution to compression

Answer 17

Block is too warm or Blade is too dull

Cool the block or new blade

Question 18

cause and resolution to lines/scores

Answer 18

Defect in blade or Calcification (notify path)

New blade

Question 19

cause and resolution to debris in cryostat

Answer 19

Static electricity

Humidify room or wipe down cryotome with alcohol

Question 20

what disinfectant used at end of day

Answer 20

70% ethanol

Question 21

how should Oxivir/Cavicide be used

Answer 21

when cryostat is defrosted and decontaminated

Question 22

what method of disinfectant is dangerous for cryostat

Answer 22

heating chambers to vaporize formalin or gluteraldehyde

Question 23

cons of UV light disinfectant

Answer 23

cannot pentrate dirt so it has to be clear before use

Question 24

what causes the cryostat to overheat

Answer 24

dusty coils

Question 25

what pH is calcium soluble at

Answer 25

4.5 or less

Question 26

what solutions are used to routinly used to decal

Answer 26

formic acid with formalin (3-10 days) HCL or nitric acid when more rapid is needed (<2 days)

Question 27

T/F tissues can be decalcified whenever

Answer 27

F - tissues must be fixed before decal

Question 28

what hazard can occur when decal with HCl

Answer 28

must be washed after HCl as mixing with formalin = bis-chloromethyl ether (carcinogen)

Question 29

what 3 methods are used in decal

Answer 29

simple acid ion exchange resins EDTA

Question 30

how does simple acid decal work

Answer 30

submerge in solution with agitation to prevent calcium ion surrounding the tissue, then replace solution

Question 31

how does ion exchange resins decal work

Answer 31

resins exchange ammonium for calcium ions to prevent saturating solution = quicker decal and less replacement

Question 32

how does EDTA decal work

Answer 32

binding metal ions without affecting other tissue components = good to use where acids may destroy labile tissue. BUT takes weeks to complete

Question 33

what 3 methods are used to detect endpoint

Answer 33

chemical radiography physical

Question 34

how does chemical endpoint detection work

Answer 34

decal solution is neutralized with ammonium hydroxide then ammonium oxalate to form calcium oxalate (white precipitate) white precipitate = calcium present and more decal needed

Question 35

how does radiography endpoint detection work

Answer 35

Ca2+ is solid white on X rays

Question 36

how does physical endpoint detection work

Answer 36

bending the tissue to determine if fully decal (unreliable and not recommended as bending creates artifacts)

Question 37

after decal, what is used to neutralize the residual acid

Answer 37

lithium carbonate

Question 38

how is overdecal recognized

Answer 38

poor nuclear staining pale red nuclei = loss of basephilia

Question 39

how to correct for over decal

Answer 39

sodium bicarbonate overnight and restain