For optimal results, the patient should avoid meat, tea, coffee, or drugs on the day of the test.
Specimen accepted daily, 24 hours
Blood creatinine should be ordered and sent to the laboratory during urine collection. Both blood and urine creatinine measurements are necessary to calculate creatinine clearance. If a corrected clearance is requested, the patient`s height and weight must be written on the requisition. For timed urine collection, instruct the patient to void at the beginning of the collection period and discard the specimen. Collect all urine including the final specimen voided at the end of the collection period. Containers must be labeled with patient`s full name, room number, date and time collection started, and date and time collection finished.