Principle of Measurement

1. Uricase–Peroxidase (Uricase/POD) Method (Most common)

Reaction Process

1. Uricase converts uric acid into allantoin, CO₂, and hydrogen peroxide (H₂O₂).

2. H₂O₂ reacts with a chromogenic dye in the presence of peroxidase, forming a colored quinone-imine or similar compound.

3. The color intensity is measured photometrically between 520–550 nm, proportional to uric acid concentration.

Advantages:

• High specificity

• Minimal interference from glucose, ascorbate, and bilirubin (depending on kit formulation)

• Widely compatible with automated analyzers

Reagent Components

A typical uric acid reagent kit contains:

R1 (Buffer/Enzyme reagent)

• Phosphate buffer

• Uricase enzyme

• Peroxidase enzyme

• Chromogenic dye precursors

• Surfactants and stabilizers

• Preservatives

R2 (Color reagent) (in two-reagent systems)

• Dye enhancer or color-developing components

• Auxiliary stabilizers

• Preservatives

Some kits come as single ready-to-use reagent.

Packaging Formats

• Liquid-stable reagents (most common)

• Two-reagent packs (R1 + R2)

• Analyzer-specific cartridges

• Optional calibrators and controls

Common volumes: 25 ml, 50 ml, 100 ml, 250 ml, and larger bulk sizes.

Sample Types

• Serum

• Plasma (heparin, EDTA)

• Urine (usually diluted before measurement)