====1.FORMALIN PREPARATION AND BOUIN’S FLUID PREPARATION====
**1.PURPOSE OF EXAMINATION**
To lay down the procedure for preparation of 10% buffered formalin &Bouin’s fluid for tissue fixation in Histo-pathology section at NCHLS Surat.

**2.PRINCIPLE AND METHOD OF PROCEDURE USED FOR EXAMINATION**
Process by which the constituents of the cells and therefore, of tissues, are fixed in a chemical and partly also in a physical state so that they will withstand subsequent treatment with various reagents with a minimum loss, significant distortion or decomposition and keep the tissue in as life like a manner as possible.  

**3.STAFF RESPONSIBLE**
 lab. Technician under supervision of resident doctor/tutor.

**4.PERFORMANCE CHARACTERISTICS**
 NA

**5.TYPE OF SAMPLE**
 NA

**6.PATIENT PREPARATION**
NA

**7.TYPE OF CONTAINER AND ADDITIVES**
 Clean, labeled plastic close container

**8.REQUIRED EQUIPMENTAND REAGENTS**
  *Formalin: 40% formaldehyde, tap water, K2Hpo4, NaH2po4, 
  *Bouin’s fluid: Picric acid, Formaldehyde, acetic acid.

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

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

**11.PROCEDURE(STEPS)**
  *Buffered Formalin Preparation: (20 liter buffered formalin)
     *Take 2 liter of 40% formaldehyde solution in one big container
     *Add 18 liter of tap water in container containing 40% formaldehyde.
     *Mix well and add 130 gm K2HPO4 and 80 gm NaH2PO4
     *Mix well till all ingredients have dissolved.
     *Store this solution in closed container for use. 
  *Bouin’s Fluid: 100 ml	
     *Take 75 ml picric acid in one beaker.
     *Add 25 ml of 40% Formaldehyde. 
     *Add 5 ml Acetic acid in it.
     *Mix well and store in closed container.
	
**12.QUALITY CONTROL PROCEDUR**
NA

**13.INTERFERENCE**
Inadequate quality/improper dilution

**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 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 VALUES WHERE APPROPRIATE**
NA

**19.LABORATORY CLINICAL INTERPRETATION**
NA

**20.POTENTIAL SOURCE OF VARIATION**
NA

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