Oxalate, Timed Urine

Alternate test name

Lab area

Clinical Biochemistry - General

Method and equipment

Equipment : Roche Cobas Pro c503

Method : The enzymatic reactions involved in the assay procedure

Oxalate is oxidized to carbon dioxide and hydrogen peroxide by oxalate oxidase. The hydrogen peroxide reacts with 3-methyl-2-benzothiazolinone hydrazone (MBTH) and 3-(dimethylamino) benzoic acid (DMAB) in the presence of peroxidase to yield an indamine dye which has an absorbance maximum at 590 nm.

The intensity of the color produced is directly proportional to the concentration of oxalate in the sample.

Expected turn-around time

8 days

Shipping information

Background and clinical significance

Oxalate was confirmed as a normal constituent of urine in 1951, but only recently has the significance of calcium oxalate crystalluria and its relationship to urinary tract stone formation been fully recognized1. Formation of the sparingly soluble calcium salt of oxalate in the urinary tract is considered the major factor in urolithiasis.2 Oxalate in urine may arise either as an end product of intermediary metabolism or from dietary sources. A decreased excretion of oxalate in the urine is associated with hyperglycinemia and hyperglycinuria.3 An increased excretion of oxalate can be attributed to increases in ingestion of oxalate precursors or oxalate rich foods, formation of oxalate due to metabolic defects such as in primary hyperoxaluria, and absorption of oxalate in a number of gastrointestinal disorders that produce severe fat malabsorption. This latter group includes patients with inflammatory bowel disease, ileal resection, biliary diversion, pancreatic insufficiency, sprue, small intestinal stasis with bacterial overgrowth, and following jejunoileal bypass or resection for the treatment of obesity