Oxalate, 24Hr Urine/Creatinine
Oxalic Acid, 24-Hour Urine with Creatinine
Urine (24 hour collection)
10 mL aliquot of a 24-hour collection
Plastic urine container
Avoid vitamin C supplements and vitamin C-rich foods (eg, citrus fruits like oranges, orange juice; vegetables like broccoli, tomatoes, peppers, potatoes) for 48 hours prior to collection
Collect urine with 25 mL of 6N HCL to maintain a pH below 3. Refrigerate during and after collection.
Maintain acidified urine at room temperature. Acid prevents crystallization and conversion of ascorbate (vitamin C) to oxalate.
Room temperature: 6 days
Refrigerated: 7 days
Frozen: 4 months
Random urine is unacceptable