1. PURPOSE OF EXAMINATION: To lay down the procedure for Frozen section in Histopathology section at NCHLS Surat.
2. PRINCIPLE AND METHOD OF PROCEDURE USED FOR EXAMINATION: When tissue is rapidly cooled down, water contained in it converts into ice which act as fixatives, supportive media and enable the cutting of thin section.
3. STAFF RESPONSIBLE: lab. Technician under supervision of resident doctor/tutor.
4. PERFORMANCE CHARACTERISTICS: NA
5. TYPE OF SAMPLE: Frozen section
6. PATIENTS PREPARATIONS: NA
7. TYPE OF CONTAINER AND ADDITITVES: Clean labelled containers, jars
8. REQUIRED EQUIPMENTS AND REAGENTS:
EQUIPMENTS: Cryostat
REAGENT: Normal saline, H&E stain, absolute alcohol, Xylene, DPX.
9. ENVIRONMENTAL AND SAFETY CONTROL: Universal safety precautions
10. CALIBRATION PROCEDURE (METROLOGICAL TACEBILITY): temperature measurement and calibration for section thickness done by manufacturer.
11. PROCEDURE (STEPS):
• When frozen section is demanded by clinician respective authorized signatories are informed for frozen section and approximate time.
• Cryostat is switched on the previous night(5-6 hrs before) and temperature is noted.
• When specimen comes for frozen section, patient’s identity is checked.
• The specimen is then given a frozen no.(eg. F-10) which is also tagged to the patient’s requisition form.
• If more than one specimen of the same patient is sent for frozen section, they are labelled in alphabetical order (eg. FS1A, FS1B, FS1C…)
• Grossing of specimen done and representative sections are submitted for freezing in cryostat.
• Place the representative tissue on a metal cryostat chuck after applying 1-2drops of tissue adherent (gung) on the chuck.
• Pour 1-2 drops of normal saline on the tissue.
• Put the chuck with the tissue on a metal tray of the cryostat for freezing the tissue.
• When the temperature of the cryostat attains -250C to -300C, trim the tissue to get full exposure.
• Cut the section at 5u thickness and pick up from the knife to put it on previously labelled glass slides.
• Sections are fixed in oven for 2minutes at 500C to 600C.
• Sections are then stained with H&E stain.
• Reporting of frozen section is done by authorized signatories for frozen section(professor/additional professor)
• The report is informed telephonically to concerned surgeon after verifying the identity of the patient and the person to whom it is informed.
• Same written report is dispatched immediately.
• Entry of diagnosis,date,and name of reporting pathologists, technicians, TAT and telephonic conveyance of report to surgeon is written down in the frozen register.
• Remaining tissue bit and uncut thawed frozen bits are placed in a container with 10% buffered formalin. A HP no. Is then given to this specimen.
• When final diagnosis is made, it is entered against its frozen diagnosis in frozen register.
• The frozen section slides are stored separately in storage cabinets.
• After completion of procedure, cryostat is cleaned with Hypochlorite solution, trimming and blade are removed and oiling of machine is done.
12. QUALITY CONTROL PROCEDURE: Section is examined for proper staining, processing and same sections are reviewed by another authorized signatories.
13. INTERFERENCE: temperature of cryostat
14. PRINCIPLE OF PROCEDURE FOR CALCULATING RESULTS INCLUDING, WHERE RELEVENT, THE MEASUREMENT OF UNCERTAINITY OF MEASURED QUANTITY VALUES:NA
15. BIOLOGICAL REFERENCE INTERVALS OR CLINICAL DECISION VALUES:NA
16. REPORTABLE INTERVAL OF EXAMINATION RESULTS: within 30 minute of receipt of tissue.
17. INSTRUCTION FOR DETERMINING QUANTITATIVE RESULTS WHEN RESULTS IS NOT WITHIN THE MEASUREMENT INTERVAL: NA
18. ALERT /CRITICAL VALUES, WHERE APPROPRIATE: NA
19. LABORATORY CLINICAL INTERPRETATION: NA.
20. POTENTIAL SOURCE OF VARIATION: NA
21. REFERENCE: Histopathological laboratory techniques by Culling’s.