Health care professionals require varying amounts of urine depending on the type of urine test, according to WebMD. During a clean-catch midstream one-time urine collection, the patient collects approximately 2 fluid ounces, or 60 milliliters, in a collection cup. A double-voided urine sample collection uses the same amount for testing.
During a 24-hour urine collection test, the patient must collect all of his urine for a 24-hour period, explains WebMD. The collection period typically starts during the morning, but the patient does not collect the first sample of urine. The first instance of urination marks the beginning of the 24-hour collection period.