Estimation of Sodium and Potassium in Blood: 

1.  Estimation of Sodium in Blood:

 

§  Method:

§  Principle: The method is based on the reaction of sodium with a chromogen producing a chromophore whose absorbance is directly proportional to sodium concentration in the test specimen which can be photometrically measured.

§  Procedure:

	Test	Standard	Blank
Reagent	1000μl	1000μl	1000μl
Standard		10μl
Sample	10μl

 

§  Requirement: i. Sodium reagent

ii. Test-tube

iii. 1.0 Cm cuvette

iv. General lab equipment

v. Colorimeter or Semiauto-analyser

§  Incubation: Incubated the assay mixture for 5min at room temperature. Measured the absorbance of the standard and sample against the reagent blank at 630nm.

 

§ Calculation: Sodium in (mEq/L) = OD of Sample / OD of Stand. x Conc. Of Standard (150)

 

§  Linearity: This produce is linear up to 180mEq/L. If values exceed this limit, we should dilute the sample with distilled water and multiply the results with the proper dilution factor.

 

§  Normal Value: In serum/Plasma – 135-155mEq/L.

 

§  Clinical Significance: Sodium is the major cation of extra-cellular fluid. It plays a central role in the maintenance of the normal distribution of water and the osmotic pressure in the various fluid. The main source of body sodium is sodium chloride contained in ingested foods. Only about 1/3^rd of the total body’s sodium is contained in the skeleton since most of its present in the extra-cellular body fluids.

22.  Estimation of Potassium in Blood:

 

§  Method: Turbidimetric method.

§  Principle: The amount of potassium is determined by using sodium tera phenyl born in a specifically prepared mixture to produce a colloidal suspension. The turbidity of which is proportional to potassium concentration in the range of 2-7 mEq/L. Tetra phenyl boron+k+ ‘White Turbidity’. The amount of the turbidity produce is directly proportional to the concentration of potassium in the sample.

 

NaB(C6H5)4 + K+   ------------>   KB(C6H5)4 (White precipitate of potassium tetraphenyl)

 

§  Procedure:

	Test	Standard	Blank
Reagent	1000μl	1000μl	1000μl
Standard		20μl
Sample	20μl

 

§  Requirement: i. Potassium Reagent

ii.  Test-tube

iii. Cuvette

iv. General lab equipment

v. Colorimeter or semiauto analyser

§  Incubation: We will mix the mixture well and incubate the assay mixture for 5mins at room temperature and then we measured the absorbance of the standard and sample against the reagent blank at 630nm.

§  Calculation: Potassium in mEq/L = OD of Sample / OD of Stand x Conc. Of Standard (5)

§  Linearity: This procedure is linear upto 7 mEq/L. If the values exceed his limit, then we should dilute the sample with distilled water and multiply the results with proper dilution factor.

§  Normal Value: Serum/Plasma – 3.5-5.5 mEq/L.

§  Clinical Significance: Potassium is estimated by the turbidimetric method. Potassium ions in the specimen react with sodium tetraphenyl boron to produce an insoluble potassium tetraphenyl boron resulting in a turbid suspension.