Estimation of Serum uric acid

1. Estimation of Serumuric acid

2. Uric acid • Uric acid is the end product of purine catabolism. • •Formation of uric acid is principally endogenous mainly of tissue nucleoprotein breakdown but some amount is also formed from purine containing compounds present in food. •The serum uric acid levels are affected by diet • Purine Uric acid

4. Clinical significance; • Normal range=4-8 mg/dL • Female: (2.5-6.0 mg/dl) • Male: (3.4-7.0 mg/dl) • A. Hyperuricemia; • 1. Uric acid is the end product of purine metabolism and hence high rate of purine metabolism increases uric acid level. • High level is observed in • 1. Gout • 2. Arthritis • 3. Cancer and leukemia • 4. Polycythemia • 5. Toxemia of pregnancy • B. Hyporuricemia:Low level is seen in congenital deficiency of xanthine oxidase.

6. : Uric acid is oxidized by uricase to allantoin with the formation of hydrogen peroxide. In the presence of peroxidase (POD), a mixture of dichlorohydroxy benzene sulphonic acid (DCHBS) and 4-aminoantipyrine (4-AAP) is oxidized by hydrogen peroxide to form a quinoneimine dye proportional to the concentration of uric acid in the sample.

7. principle • Uricase • Uric acid + 2 H2O + O2 Allantoin + CO2 + H2O2 • POD • H2O2 + 4-aminophenazone + phenol quinoneimine + 4 H2O • Color intensity is directly proportional to [UA] in the specimen

8. Procedure

9. Calculation • Ab.(Assay) • Concentration of uric acid= ------------ *Standard solution • (mg/dL)=Ab(standard) • Stock Standard=10mg/100mL • 25µL for working • Wt(mg) V(mL) • --------- --------- • 10 100ml • X 0.025mL X=0.0025mg/0.025mL