A new concept for urate in human serum: Enzymatic assay of total urate (protein-bound &amp; loosely associated) in serum using 3,5-dichloro-2-hydroxybenzenesulphonic acid/4-aminophena zone chromogenic system

Ahmed Nabil Hegazi

doi:10.1186/ar313

Abstract

A Modification of the method previously introduced by Fossati et al [1] is accomplished for the estimates of protein bound urate, for the first time, as well as the loosely associated urate in serum. The Cvs ranged from 14 to 23 for the same- day precision and 21 to 37 for the between-run precision for concentration ranged from 0.303 to 2.458 mmol/L. The evidences for being highly specific have been discussed. Besides, a tentative explanation why urate in serum and pure uric acid solution behave differently towards the enzymatic color reagent has been introduced. As a primary act, the mean urate value in 29 males was 1.08 mmol/L while the average value was 0.76/ mmol/L in 14 normal non-pregnant women.

Highlights

A Modification of the method previously introduced by Fossati et al [1] is accomplished for the estimates of protein bound urate, for the first time, as well as the loosely associated urate in serum.The Cvs ranged from 14 to 23 for the same- day precision and 21 to 37 for the between-run precision for concentration ranged from 0.303 to 2.458 mmol/L
The competition between serum urate and the suggested enzymatic color reagent after the addition of 50 μL of the 0.4 mol/L sodium hydroxide solution to the 50 μL of serum prior the addition of the enzymatic color reagent could be understood on the basis of the existence of both the lactam-lactim toutomers of serum urate
In sodium hydroxide solution enolization of serum urate might take place i.e., transformation to the lactim toutomer which not react with the enzymatic color reagent

Summary

Introduction

A Modification of the method previously introduced by Fossati et al [1] is accomplished for the estimates of protein bound urate, for the first time, as well as the loosely associated urate in serum. The Cvs ranged from 14 to 23 for the same- day precision and 21 to 37 for the between-run precision for concentration ranged from 0.303 to 2.458 mmol/L. The evidences for being highly specific have been discussed. A tentative explanation why urate in serum and pure uric acid solution behave differently towards the enzymatic color reagent has been introduced. The mean urate value in 29 males was 1.08 mmol/L while the average value was 0.76/ mmol/L in 14 normal non-pregnant women

Materials & Method

Procedure

Results

Discussion

Ball EG