Urine for a urinalysis can be collected at any time. A sufficient sample is required for accurate results.

In some cases, a first morning sample may be requested because it is more concentrated and more likely to detect abnormalities. Participants were instructed as follows:

• empty your bladder before lying down to sleep
• do not urinate during the night
• collect the first urine from the first urination in the morning
• keep the urine specimen cold.

One to two ounces of urine were collected in a clean container and were brought by the participant to 1A visit 2.