The health care provider ordered a 24-hour urine specimen to test the renal function of a patient ...

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In most 24-hour specimen collections, you will need to discard the first voided specimen and then start collecting urine in a special container that already has a preservative added. Depending on the test, the urine container may need to be kept cool by placing it in a container of ice. Patient education must include an explanation of the test, an emphasis on the need to collect all urine voided during the prescribed time period, and how to avoid contaminating the specimen with stool or toilet paper. Careful documentation of the start and stop time of the test, as requested by the laboratory, will improve testing accuracy. A 24-hour specimen can be started at any time after obtaining and discarding the first voided specimen.