Estimation of calcium in blood

ESTIMATION OF CALCIUM IN BLOOD
O-CRESOL PHTHALEIN COMOLEXONE METHOD:

PRINCIPLE:

in alkaline sol, CPC forms a red chromophore with calcium, which is measured at 570-580nm. Interfering with magnesium ions is reduced by adding 8-hydroxyquinoline and buffering the reaction mixture to near PH12.

REAGENTS:

1. buffer sol
2. color reagent
3. std (10mg%)

PROCEDURE:

    pipette into clean dry “tt” labeled as blank(B), std (S) and test(T), the following quantities
                   B            S            T
1        Buffer sol         2Ml           2Ml           2Ml
2          Color reagent         2Ml            2Ml           2Ml
3        Deionised water       0.2ml           -           -
4        Standard           -         0.2ml           -
5        Serum          -           -          0.2ml

Mix well and incubate at room temp for 5min. Measure the absorbance of (T), and (S) against (B) on a spectrophotometer at 570nm, within 30min.

Calcium in mg% = abs of (T)/ abs of (S) X 10

CLINICAL SIGNIFICANCE:

calcium is found in 3 main compartments: bone, soft tissue, and extracellular fluid. serum calcium levels are elevated in hyperparathyroidism, secretion of parathyroid-like hormones by malignant tumors; vitD in xes, milk-alkali syndrome, osteolytic disease such as multiply myeloma, invasion bone by metastatic cancer Paget's disease of bone borek's sarcoid
              decreased  serum calcium levels are observed in hypoparathyroidism vitD deficiency (rickets osteomalacia)

NORMAL VALUES:

serum calcium (adult's) =  8.7- 11.0 mg%