Determination of serum oxalate using peroxyoxalate chemiluminescence of free oxalic acid.

We describe a new sensitive and specific method for determination of oxalate in human serum. By using the chemiluminescence decay of monoperoxyoxalic acid very low concentrations of oxalate (200 nmol/L) can be determined. The mean serum oxalate level in apparently healthy controls was 14.5 +/- 8.5 mumol/L. Supplementation of ascorbic acid leads to an increase in serum oxalate level. While serum oxalate concentrations of calcium oxalate stone formers (x = 16.4 +/- 9.8 mumol/L) are not significantly different from the control group, an extreme increase of serum oxalate is evident in haemodialysis patients. The serum oxalate concentration decreased during dialysis treatment from 141.4 +/- 32.1 mumol/L to 36.4 +/- 12.7 mumol/L.