Oxalate or Oxalic Acid is a metabolic breakdown product of the Kreb's Cycle in eukaryotes, and the glyoxylate cycle in other microorganisms. It can be found in the urine of humans and other mammals. Oxalate concentration can be used as a measure of kidney function where a high level of oxalate is an indicator for kidney stones which are primarily made of the insoluble salt calcium oxalate. Measuring oxalate is more accurate than measuring calcium as a marker for kidney stones because calcium is excreted at high concentrations even in normal urine. Simple and high-throughput assays for measuring oxalate concentration find wide applications. This oxalate assay kit uses a single Working Reagent that combines the oxalate oxidase reaction and color reaction in one step. The change in color intensity of the reaction product at 595 nm is directly proportional to oxalate in the sample.