Diagnostic Laboratory Section

CALCIUM

Method of Examination: Modified OCPC Method.

Principle

• Colorimetric measurement with ortho- cresolphtalein complex. The 8- hydroxy- quinoline prevents Mg from interference up to 4 mmol/Lab

Reagent composition

• Calcium dye reagent                                 
• Diethylamine - 360mmol/L
• Calcium base reagent                                  
• O-Cresolphtalein complex - 0.15 mmol /L  
• 8- Hydroxyquinoline - 17. 2 mmol /L

Laboratory procedure

	Blank	Standard	Sample
Working Reagent	1000 µL	1000 µL	1000 µL
Standard	--	10 µL	--
Sample	--	--	10 µL
Mix and incubate for 5 minute at room temperature. Read the absorbance of standard and sample against reagent blank.

Calculation

Calcium concentration (mg /dl) =(Absorbance of Sample /  Absorbance of Standard)x 10