=====6.SOP FOR MICROTOMY=====

1.	**PURPOSE OF EXAMINATION:** To lay down the procedure for cutting the processed specimen by microtome in Histo pathology section at NSHLS Surat.

2.	**PRINCIPLE AND METHOD OF PROCEDURE USED FOR EXAMINATION:** The method by which tissue can be sectioned & attached to a surface so that examination by microscopy can take place.

3.	**STAFF RESPONSIBLE: ** Senior Technician


4.	**PERFORMANCE CHARACTERISTICS: **

a.	LINEARITY: 3-10 micron.

b.	PRECISION AND ACCURACY: NA


c.	SENSITIVITY/SPECIFICITY:NA

5.	**TYPE OF SAMPLE: ** Paraffin block, Tissue cassette

6.	**PATIENT PREPARATION: ** NA


7.	**TYPE OF CONTAINER AND ADDITIVES: ** NA

8.	**REQUIRED EQUIPMENT AND REAGENTS: **


**Equipment: **Microtome

**Reagents: ** NA	

9.	**ENVIRONMENTAL AND SAFETY CONTROL: ** Universal safety precautions

10.	**CALIBRATION PROCEDURE (METROLOGICAL TRACEBILITY): ** Calibration done once in a year.


11.	**PROCEDURE (STEPS) : **
•	Bring the blocks on ice plate during cutting. Do rough cutting.

•	Trim the blocks after putting the blocks on the ice for 15 minutes.


•	First smaller tissues are cut after those bigger tissues are cut.

•	Set temperature at 65 degree C in water bath.


•	Insert the appropriate sharp knife (disposable) into the microtome at 45 degree angle.

•	Before making ribbon of section, tight all the screws of microtome.


•	To make the section ribbon set the thickness of about 3-5 micrometer.

•	The ribbon is directly transferred to water bath heated up to 5-6 degree below the melting point of wax.


•	Remove the creases from the ribbon and take the ribbon containing single large section or two to three sections on aluminized slide leaving preferably ¾ inch at one end for label and ½ inch on another end.

•	If during removing creases any damage to the section occur then ribbon should be discarded.   


•	Give the same number on the slide by diamond pencil as on the block.

•	Put the slides rack in to the oven at 65 degree temperature for 10 minute.


•	Give xylene bath for clearing for 30 minutes.

•	Rehydrate the sections by putting the slides in to increasing alcohol concentration and lastly in water.


•	Now stain the sections according to standard guidelines of different types of staining procedures.



__Note: Procedure for preparation of aluminized slide:__

•	Take white part of egg ( 4 egg approximately 50 ml)

•	Take equal quantity of glycerin & 2 drops of formalin


•	Mix it well & store in refrigerator.

•	Apply it on slide daily as per use.


12.	**QUALITY CONTROL PROCEDURE: ** NA

13.	**INTERFERENCE: **Poor quality paraffin


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: ** NA

17.	**INSTRUCTION FOR DETERMINING QUANTITATIVE RESULTS WHEN RESULT 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 Bancroft, 6th edition