====5.Tissue embedding====


**1.PURPOSE OF EXAMINATION**
To lay down the procedure for processed specimen embedding in Histo-pathology section at NCHLS Surat

**2.PRINCIPLE AND METHOD OF PROCEDURE USED FOR EXAMINATION**
A method to embed the tissue in a solid medium firm enough to support the tissue and give it sufficient rigidity to enable thin sections to be cut.

**3.STAFF RESPONSIBLE**
Lab technician

**4.PERFORMANCE CHARACTERISTICS**
NA

**5.TYPE OF SAMPLE**
 Processed tissue Bits

**6.PATIENT PREAPARATION**
NA

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

**8.REQUIRED EQUIPMENT AND REAGENTS**
Equipment- Leukhart’s block/ Plastic moulds
Reagents-paraffin wax

**9.ENVIRONMENTAL AND SAFETY CONTROLS**
Universal safety precaution

**10.CALIBRATION PROCEDURE (METROLOGICAL TRACEBILITY)**
NA 

**11.PROCEDURE (STEPS)**
__**MANUAL METHOD:**__
  *After tissue processing is over the tissues are embedded in to melted paraffin.  The procedure is called embedding.
  *Embedding means to cast the tissue in an embedding medium.
  *After completion of the tissue processing remove cassettes from tissue processor.
  *Open the cassette.
  *Put the tissue on plain and clean surface. There should not be any dust particles.
  *Place the identification number of the tissue.
  *Place a pan of square mould.
  *Pour the wax.
  *The temperature of molten paraffin wax should be 2- 3 deg. C above the melting point.
  *As soon as the wax get solidify the mould should be removed.
  *Place the identification number on the block and place it in freezer to cool. (other one is plastic mould)
  *Orientation of tissue:-
        *Most of the tissues are embedded in their largest cut surface.
        *Tubular tissues are cut transversely.
        *Skin, tissues from GIT or any epithelial surface & cut at right angles to the plane of the surface.

__**FULLY AUTOMATED METHOD**__
  *This instrument contains following units
  *Thermal unit + Dispenser wax unit (in built)
  *Cool unit

  -Switch on thermal & cooling unit. Note the temp in thermal Unit 62-65 degree C & 0 to -4 degree C in cool unit.
  - After opening cassette of tissue put in thermal unit. Take tissue from thermal unit and put it in steel mould with pressure and pour wax through dispenser unit and keep plastic cassette over it with pressure.
  - Put steel mould in cool unit
  - Immediately put label of tissue on plastic cassette.
  - After 5-6 minute take plastic cassette from steel mould in such a way that it is separated itself from steel mould.

**12.QUALITY CONTROL PROCEDURE**
NA

**13.INTERFERENCE**
 NA

**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 RESULTS IS NOT WITHIN THE MEASUREMENT INTERVAL**
NA

**18.ALERT/ CRITICAL VALUE, WHERE APPROPRIATE**
NA

**19.LABORATORY CLINICAL INTERPRETATION**
NA

**20.POTENTIAL SOURCE OF VARIATION**
NA

**21.REFERENCE**
Histopathological laboratory techniques by Bancroft, 6th edition