Potassium (k) urine test

A urine test to check potassium levels is done to look for the cause of a low or high blood potassium test result.

Urine potassium can be checked in a single urine sample. But it is more often measured in a 24-hour urine sample.

Urine collection over 24 hours

• You start collecting your urine in the morning. When you first get up, empty your bladder but do not save this urine. Write down the time that you urinated. This marks the start of your 24-hour collection period.
• For the next 24 hours, collect all your urine. Your doctor or lab will usually give you a large container that holds about 1 gallon. The container may have a small amount of preservative in it. Urinate into a small, clean container. Then pour the urine into the large container. Do not touch the inside of either container with your fingers.
• Keep the large container in the refrigerator for the 24 hours.
• Empty your bladder for the final time at or just before the end of the 24-hour period. Add this urine to the large container, and record the time.
• Do not get toilet paper, pubic hair, stool (feces), menstrual blood, or other foreign matter in the urine sample.

• In general, there's nothing you have to do before this test, unless your doctor tells you to.
• For 24-hour urine collection, your doctor or lab will usually give you a large container that holds about 1 gallon.

Each lab has a different range for what's normal. Your lab report should show the range that your lab uses for each test. The normal range is just a guide. Your doctor will also look at your results based on your age, health, and other factors. A value that isn't in the normal range may still be normal for you.

Many conditions can affect potassium levels. Your doctor will talk with you about any abnormal results as they relate to your symptoms and past health.