Potassium (K) in Urine
Potassium (K) in UrineSkip to the navigationTest OverviewA potassium test measures how much potassium is in the urine. Potassium is both an
electrolyte and a mineral. It helps balance the amounts of water
and electrolytes in the body. (Water is the amount of fluid inside and outside the body's cells.) It is also important in how nerves and muscles
work. Potassium levels often change with sodium levels. When
sodium levels go up, potassium levels go down. When sodium levels go down,
potassium levels go up. These levels are also affected by a hormone called
aldosterone. This hormone is made by the
adrenal glands. Potassium levels can be
affected by how the
kidneys are working, the blood
pH, and the amount of potassium you eat. The
hormone levels in your body, severe vomiting, and
taking certain medicines such as diuretics and potassium supplements can also affect the levels. Certain cancer
treatments that destroy cancer cells can also raise potassium levels. Many foods are rich in potassium. Some examples are potatoes, bananas, prunes, orange juice, and winter squash. A balanced diet
has enough potassium for the body's needs. But if your levels get low, it can take some time for your body to start holding on to potassium. A potassium level that is too high or too low can be
serious. Abnormal levels may cause symptoms such as muscle cramps or
weakness, nausea, diarrhea, or frequent urination.
Other symptoms may include dehydration, low blood pressure, confusion,
irritability, paralysis, and changes in heart rhythm. Why It Is DoneA urine test to check potassium levels
is done to look for the cause of a low or high blood potassium test result. How To PrepareYou do not need to do anything special to prepare for this test. Talk to your doctor if you have any concerns about the need for the test, its risks, how it will be
done, or what the results will mean. To help you understand the importance
of this test, fill out the
medical test information form(What is a PDF document?). How It Is DoneUrine 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 gal (4 L). The container has 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.
How It FeelsIt is not painful to collect a
one-time or 24-hour urine sample. RisksCollecting a
one-time or 24-hour urine sample does not cause problems. ResultsA test for potassium in the urine is a
24-hour test or a one-time (spot) test. It checks how much potassium is in the urine. Potassium is both an
electrolyte and a mineral. NormalThese numbers are just a guide. The range for "normal" varies from lab to lab. Your lab report should show what range your lab uses for "normal." Also, your doctor will evaluate your results based on your health and other factors. So a number that is outside the normal range here may still be normal for you. Results are ready in 1 day. 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. What Affects the TestYou may not be able to have the test, or the results may not be helpful, if: - You take potassium
supplements.
- You take certain medicines, such as
antibiotics that contain potassium (such as a type of
penicillin g). Other medicines that can affect the results are
nonsteroidal anti-inflammatory drugs (NSAIDs),
heparin,
insulin, glucose,
corticosteroids,
diuretics, and medicines used to treat high blood pressure
and heart disease. Natural licorice (Glycyrrhiza glabra) may also affect the results.
- You use too many laxatives.
- You have severe
vomiting.
- You don't collect exactly 24 hours of urine.
What To Think About- Potassium levels can also be checked in a blood
test. To learn more, see the topic
Potassium (K) in Blood.
- Doctors may look
at urine potassium and blood potassium levels to see if conditions or
medicines may be causing fluid or electrolyte imbalances. Urine potassium
levels are often high when blood levels are low. Or they may be low when blood levels are
high. These levels are affected by medicines and hormones.
ReferencesCitations- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Other Works Consulted- Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
- Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.
CreditsByHealthwise Staff Primary Medical ReviewerAdam Husney, MD - Family Medicine E. Gregory Thompson, MD - Internal Medicine Specialist Medical ReviewerAvery L. Seifert, MD - Urology Current as ofOctober 14, 2016 Current as of:
October 14, 2016 Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins. Last modified on: 8 September 2017
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