U-Oxalate

The following is essential for the oxalic acid assay:

- 24-hour urine collection, keep refrigerated

- indication of diuresis volume

- acidification of urine by the sampling laboratory by adding hydrochloric acid (HCl) to obtain a urinary pH between 2 and 3.

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In practice, urine can be acidified as follows:

- homogenise the entire diuresis very vigorously

- take a urine sample volume of 50 mL

- acidify this urine sample with the help of 6N hydrochloric acid

- homogenise the urine well after each addition of HCl before each pH testing

- measure pH with the help of pH paper or a pH meter.