====Tissue Fixation====

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

**2.PRINCIPLE AND METHOD OF PROCEDURE USED FOR EXAMINATION**
 Formalin preserves the tissue in life like state. Approximately 16-24 hrs requires for adequate fixation. The penetration capacity of formalin is 1 cm so large specimens shall be cut into multiple slices of 1 cm thickness.

**3.PERFORMANCE CHARACTERISTICS**
NA

**4.TYPE OF SAMPLE**
Biopsy/ Excised specimen

**5.PATIENT PREPARATION**
 NA

**6.TYPE OF CONTAINER AND ADDITIVES **
Plastic close container

**7.REQUIRED EQUIPMENT AND REAGENT:**
10% Neutral buffer formalin / Bouin’s fluid.

**8.ENVIRONMENTAL AND SAFETY CONTROLS**
 Universal safety precautions

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

**10.PROCEDURE(STEPS)**
    *For routine histopathological examination specimen should be sliced 1cm apart , put cotton soaked in 10% formalin inside it submerged in 10% buffered formalin (volume of formalin should be 10 times of the specimen) and for frozen section examination tissue should be received in normal saline.
    *If the specimen is large. Cut the specimen in smaller slice with proper orientation with 1 cm thickness.
    *If fixative is hemorrhagic, change the formalin.
    *Keep the received specimen and respective requisition form at proper suitable place.


**11.QUALITY CONTROL PROCEDURE**
NA

**12.INTERFERENCE**
 Formalin pigment

**13.PRINCIPLE OF PROCEDURE FOR CALCULATING RESULTS INCLUDING, WHERE RELEVENT, THE MEASUREMENT OF UNCERTAINITY OF MEASURED QUANTITY VALUES**
NA

**14.BIOLOGICAL REFERENCE INTERVALS OR CLINICAL DECISION VALUES**
NA

**15.REPORTABLE INTERVAL OF EXAMINATION RESULTS**
NA

**16.INSTRUCTION FOR DETERMINING QUANTITATIVE RESULTS WHEN RESULTS IS NOT WITHIN THE MEASUREMENT INTERVAL**
 NA

**17.ALERT/CRITICAL VALUE, WHERE APPROPRIATE**
 Autolysed specimen

**18.LABORATORY CLINICAL INTERPRETATION**
NA

**19. POTENTIAL SOURCE OF VARIATION**
NA

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