A potassium urine test checks the level of potassium in your body. Potassium is an important element in cell metabolism, and it’s important in maintaining the balance of fluids and electrolytes in your body. Having too much or too little potassium can be bad. Getting a urine test to determine the amount of potassium in your body can help you alter your potassium levels for better overall health.
Hyperkalemia vs. hypokalemia
Your doctor may order a potassium urine test to help diagnose certain conditions, including:
- hyperkalemia or hypokalemia
- kidney disease or injury, such as medullary cystic kidney disease
- adrenal gland problems, such as hypoaldosteronism and Conn’s syndrome
In addition, your doctor can use a potassium urine test to:
- check your potassium levels if you’ve been vomiting, had diarrhea for several hours or days, or shown signs of dehydration
- verify a high or low blood potassium test result
- monitor possible side effects of medications or drug treatments
Having too much potassium in your body is called hyperkalemia. It can cause:
- muscle weakness
- abnormal heart rhythms
If undetected or untreated, hyperkalemia can be dangerous and possibly even fatal. It’s not always detected before it causes symptoms.
Too little potassium in your body is called hypokalemia. A severe loss or drop in potassium can cause:
- muscle cramps or spasms
- acute tubular necrosis
- eating disorders, such as anorexia and bulimia
- other kidney diseases
- low blood magnesium levels, called hypomagnesaemia
- medicines, such as antibiotics, blood thinners, nonsteroidal anti-inflammatory drugs (NSAIDs), and blood pressure medication like angiotensin II receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitors
- renal tubular acidosis
- excessive use of diuretics or potassium supplements
- type 1 diabetes
- alcoholism or heavy drug use
- Addison’s disease
A low level of potassium in your urine may be caused by:
- adrenal gland insufficiency
- eating disorders, such as bulimia
- excessive sweating
- excessive laxative use
- magnesium deficiency
- certain medicines, including beta blockers and nonsteroidal anti-inflammatory drugs (NSAIDs), water or fluid pills (diuretics), and some antibiotics
- excessive vomiting or diarrhea
- excessive alcohol use
- folic acid deficiency
- diabetic ketoacidosis
- chronic kidney disease
A potassium urine test has no risks. It involves normal urination and won’t cause any discomfort.
Before taking a potassium urine test, ask your doctor if you need to temporarily stop taking any prescription or over-the-counter medications or supplements. Drugs and supplements that can affect the results of a potassium urine test include:
- beta blockers
- blood pressure medication
- diabetes medications or insulin
- herbal supplements
- potassium supplements
- nonsteroidal anti-inflammatory drugs (NSAIDs)
Your doctor or nurse may instruct you to clean your genital area before you begin the urine sample collection. Do NOT stop taking any medications until you’ve spoken with your doctor or nurse. You will also need to keep the urine sample clean of pubic hair, stool, menstrual blood, toilet paper, and other potential contaminants.
There are two different potassium urine tests: a single, random urine sample and a 24-hour urine sample. What your doctor is looking for will determine which test you take.
For a single, random urine sample, you will be asked to urinate into a collection cup at your doctor’s office or at a lab facility. You will give the cup to a nurse or lab technician and it will be sent for testing.
For a 24-hour urine sample, you will collect all of your urine from a 24-hour window into a large container. To do this, you will begin your day by urinating into a toilet. After that initial urination, you will begin collecting your urine every time you urinate. After 24 hours, you will turn over your collection container to a nurse or lab technician and it will be sent for testing.
If you have any questions or concerns about the potassium urine test or how to collect your urine samples, talk with your doctor or nurse.
A normal potassium range, or reference range, for an adult is 25–125 milliequivalents per liter (mEq/L) per day. A normal potassium level for a child is 10–60 mEq/L. These ranges are only a guide, and actual ranges vary from doctor to doctor and lab to lab. Your lab report should include a reference range for normal, low, and high potassium levels. If it doesn’t, ask your doctor or lab for one.
Following a potassium urine test, your doctor may also request a potassium blood test if they think it will help confirm a diagnosis or detect something that the urine missed.
A potassium urine test is a simple, painless test to see if your potassium levels are balanced. Having too much or too little potassium in your body can be harmful. If left untreated, it can lead to serious health issues. If you experience any symptoms of having too little or too much potassium, see your doctor. The earlier you detect and diagnose an issue, the better.