A split urine test is used to determine whether the protein in your urine is caused by a condition called orthostatic proteinuria. For reasons that are not well understood, proteinuria (protein in the urine) occurs in some people while standing or sitting, but not while lying down.
Orthostatic proteinuria is a harmless condition that can occur in young people. Generally, no further testing or treatment is necessary after diagnosis. More detailed information about orthostatic proteinuria is available by subscription. (See "Orthostatic (postural) proteinuria".)
You will need to collect all of your urine for 24 hours. Pick a day when this would be convenient. Men may want to buy an inexpensive urinal for easy collection; women may buy an inexpensive urine hat, which fits over the toilet.
You will also need two jugs and a funnel. Two half-gallon plastic jugs (eg, milk jugs), thoroughly rinsed, are adequate. Label the two jugs:
Perform the following steps on the day that you are going to collect the urine:
●When you first get up, urinate and throw away this urine.
●For the rest of the day, collect all of the urine each time you go to the bathroom. Put this urine into the daytime urine jug. You can do your normal daily activities, but strenuous exercise should be avoided.
●In the evening, lie down two hours before you go to sleep. Just before sleeping, go to the bathroom for the last time and add this urine to the daytime jug. Lying down for two hours helps to avoid mixing urine made at night with urine made during the day.
●If you need to go to the bathroom during the night, be sure to collect this urine and put it in the nighttime urine jug.
●The next morning (approximately eight hours after going to sleep), collect the first morning urine and put in the nighttime urine jug.
●Take the two jugs to the laboratory.
Your doctor or nurse's office will notify you when the results are available.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
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Patient information: Chronic kidney disease (The Basics)
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Assessment of urinary protein excretion and evaluation of isolated non-nephrotic proteinuria in adults
Orthostatic (postural) proteinuria
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