• On day 1, urinate into the toilet when you get up in the morning.
• Afterwards, collect all urine in a special container for the next 24 hours.
• On day 2, urinate into the container when you get up in the morning.
• Cap the container. Keep it in the refrigerator or a cool place during the collection period. Label the container with your name, the date, the time of completion, and return it as instructed.

FOR INFANTS
Thoroughly wash the area around the urethra. Open a urine collection bag (a plastic bag with an adhesive paper on one end), and place it on the infant. For males, the entire penis can be placed in the bag and the adhesive attached to the skin. For females, the bag is placed over the labia. Diaper as usual over the secured bag.

This procedure may take a couple of attempts -- lively infants can displace the bag, causing the specimen to be absorbed by the diaper. The infant should be checked frequently and the bag changed after the infant has urinated into the bag. The urine is drained into the container for transport to the laboratory.

Deliver it to the laboratory or your health care provider as soon as possible upon completion. The laboratory will measure the volume of urine in the specimen.

• Sodium - urine
• Potassium - urine
• Urea nitrogen - urine

800 to 2000 ml/day (with a normal fluid intake of about 2 L/day)

Normal value ranges may vary slightly among different laboratories.

Note: ml/day = milliliter per day; L/day = liters per day

• Diabetes insipidus - renal
• Diabetes insipidus - central
• Diabetes mellitus
• High fluid intake
• Some forms of kidney failure
• End-stage renal disease
• Use of diuretic medications