Measurement of Calcium

Method: - Enzymatic colorimetric.

Principle: - Calcium ions react with o-cresolphthalein-complexone in an alkaline medium to form a purple colored complex. The absorbance of this complex is proportional to the calcium concentration in the sample.

Apparatus required:

     ®   Colorimeter

     ®   Test tubes with rack

     ®   Pipettes

     ®   Timer+Marker

     ®   Blood collection set

Reagents required:-

   Ø Color Reagent

   Ø Buffer Solution

   Ø Standard

***Concentration of standard: - 02 mg/dl

Reagent Preparation: - Add     RGT     to   BUF   in equal volumes as required and allow to stand for 10 minutes at room temperature before use.

Sample/Specimen:

      ®  Serum

      ®  Haparinized plasma which must be free from haemolysis.

Procedure/Assay:-

   Ø Wavelength- 570 nm, Hg 578 nm

   Ø Cuvette-1cm light path

   Ø Temperature-25°C

   Ø Reagent  blank

Pipette into test tubes as follows:

Mix incubation for 10 min. at 20-25°C or for 5 min. at 37°C.measure the absorbance of the sample and the standard against the reagent blank within 60 minutes.

Calculation: -

Test Result:-Calcium reference (normal) range: 8.1-10.4  mg/dl    or    2.02-2.60  mmol/l