Potassium Test-Why am I having this test?

Potassium Test is done to determine how much potassium you have in your blood. Potassium is an important nutrient that helps your muscles and nerves function normally. It also helps maintain a stable acid–base balance in your bloodstream.

Most of the body’s potassium is inside of cells, and only a very small amount is in the blood. Because the amount of potassium in the blood is so small, minor changes can have big effects.

Potassium blood levels are affected by many factors. This test may be done as part of routine blood work. It may also be done:

• To help diagnose the cause of a serious illness.
• To monitor treatment for conditions such as heart disease or heart failure.
• To check for problems with kidney function.
• To monitor the presence of certain hormones in your blood.
• To check for problems related to how much salt (sodium) leaves your body through urination.
• To monitor the effect of certain medicines you may be taking.

What is being tested?

This test measures the amount of potassium in your blood.

What kind of sample is taken?

A blood sample is required for this test. It is usually collected by inserting a needle into a blood vessel or by sticking a finger with a small needle.

Tell a health care provider about:

• All medicines you are taking, including vitamins, herbs, eye drops, creams, and over-the-counter medicines.
• Any medical conditions you have.

How are the results reported?

Your test results will be reported as a value that indicates the amount of potassium in your blood. Your health care provider will compare your results to normal ranges that were established after testing a large group of people (reference ranges). Reference ranges may vary among labs and hospitals. For this test, common reference ranges are:

• Adult or elderly: 3.5–5.0 mEq/L or 3.5–5.0 mmol/L (SI units).
• Child: 3.4–4.7 mEq/L.
• Infant: 4.1–5.3 mEq/L.
• Newborn: 3.9–5.9 mEq/L.

What do the results mean?

Results that are within the reference range are considered normal. Test results that are higher than normal can result from many things, including:

• Too much dietary intake of potassium-rich foods.
• Too much IV intake of potassium-rich solutions.
• Kidney failure.
• Addison’s disease.
• Decreased production of the aldosterone hormone by the kidneys (hypoaldosteronism).
• Crush injury to tissues.
• The breakdown of red blood cells in the spleen (hemolysis).
• Transfusion of broken-down (hemolyzed) blood cells.
• Infection.
• A condition in which your blood is too acidic (acidosis).
• Dehydration.
• Side effect from medicine.

Test results that are lower than normal can result from:

• Not enough dietary intake of potassium-rich foods.
• Not enough IV intake of potassium-rich solutions.
• Complications from a burn.
• Conditions that cause excessive or prolonged diarrhea or vomiting.
• Use of medicines that encourage extra fluid loss from your body through urination (diuretics).
• Too much production of aldosterone hormone by the kidneys (hyperaldosteronism).
• Cushing’s syndrome.
• Kidney disease.
• Consuming too much licorice. When licorice is eaten in large amounts, it functions like the hormone aldosterone.
• A condition in which your blood is not acidic enough (alkalosis).
• Use of insulin.
• Taking in too much sugar (glucose) as a treatment for a low blood glucose level.
• Excess fluid in the abdomen (ascites).
• Narrowing or partial blockage of blood vessels to the kidney (renal artery stenosis).
• Cystic fibrosis.
• Complications from trauma.
• Surgery.

Talk with your health care provider about what your results mean.

Questions to ask your health care provider

Ask your health care provider, or the department that is doing the test:

• When will my results be ready?
• How will I get my results?
• What are my treatment options?
• What other tests do I need?
• What are my next steps?

Summary

• The potassium (K) test is done to determine how much potassium you have in your blood. Potassium is an important nutrient that helps your muscles and nerves function normally.
• This test may be done as part of routine blood work or to help diagnose or monitor certain conditions.
• A number of conditions can lead to a potassium level that is higher or lower than normal.
• Make sure you talk with your health care provider about what your results mean.