Comparative study of two commercial enzymatic kits for determining oxalate concentrations in urine.
We performed a comparative study of two commercial kits for determining oxalate in urine. These were: (a) an oxalate decarboxylase-based assay (Boehringer Mannheim); (b) an oxalate oxidase-based assay (Sigma). The within-run and between-run imprecision were found to be similar in both methods. The recovery was 94% with the oxalate decarboxylase method. The pH of the specimen had a major effect on the recovery obtained by the oxalate oxidase method (66-86% at pH = 2.5 and 37-68% at pH = 1.5). The decarboxylase method was linear up to at least 2224 mumol/L and the oxidase method was linear up to at least 890 mumol/L. We also studied the interference of ascorbic acid in both techniques and found a positive bias with the oxidase method and a negative bias using the decarboxylase method. The correlation coefficient was 0.592.
Ruiz Santamaria
J
J
Servicio de Análisis Clínicos, Hospital Son Dureta, Palma de Mallorca, Spain.
Coll
R
R
Fuentespina
E
E
D001205:Ascorbic Acid / Q000652:urine; D002262:Carboxy-Lyases; D006801:Humans; D006863:Hydrogen-Ion Concentration; D010070:Oxalates / Q000652:urine*; D010088:Oxidoreductases; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results
D010070:Oxalates; D011933:Reagent Kits, Diagnostic; D010088:Oxidoreductases; C020598:oxalate oxidase; D002262:Carboxy-Lyases; C021915:oxalate decarboxylase; D001205:Ascorbic Acid