The day before the urine collection, do not take any extra vitamin C (beyond that in your multi-vitamin). On the morning of each urine collection, do not take any vitamins, food, or coffee before collecting your urine sample. The sample must be taken BEFORE 10 AM.
- The first thing in the morning, urinate as usual, not saving the urine.
- Drink 1 or 2 cups of water. Do not eat or drink anything except water until after you collect the second urine sample. (Thyroid pill is okay.)
- Collect a sample of the second morning urine in a clean plastic or glass container. This collection must be taken BEFORE 10 AM.
- Refrigerate this sample.
- Follow steps 1 to 3, collecting your second morning urine in a second container.
- In a third container, mix half of each day’s urine. This is the sample you will write your name on and take to the lab designated by your doctor. The leftover urine from each day can be discarded.
Important: Make sure to REFRIGERATE the urine samples in the containers until you take them to the lab. Also, put the samples in a paper bag to avoid sunlight exposure.
Try to do the first urine collection on a Sunday and the second on a Monday.