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A potassium test is used to measure the amount of potassium in your blood. Potassium is an electrolyte that’s essential for proper muscle and nerve function. Even minor increases or decreases in the amount of potassium in your blood can result in serious health problems.
Your doctor may order a potassium test if they suspect you have an electrolyte imbalance or as part of a routine check-up.
Potassium is an electrolyte. Electrolytes become ions when they’re in a solution, and they conduct electricity. Our cells and organs require electrolytes to function normally.
A potassium test is performed as a simple blood test and carries few risks or side effects. The blood sample drawn by your healthcare provider will be sent to a laboratory for analysis, and your doctor will review the results with you.
A potassium test is often performed as part of a basic metabolic panel, which is a group of chemical tests run on your blood serum. Your doctor may order a potassium test during a routine physical or for a variety of other reasons, including:
The test will help reveal whether your potassium level is normal.
Prior to the test, your doctor may want you to stop taking any medications that could affect the test results. Ask your doctor for specific instructions prior to test day.
The potassium test is performed like other routine blood tests. A site on your arm, usually the inside of your elbow or the back of your hand, will be cleaned with antiseptic. Your health care provider will wrap a band around your upper arm to create pressure so that your veins swell.
A needle will be inserted into your vein. You may feel a sting or the prick of the needle. Blood will then be collected into a tube. The band and the needle will then be removed and the site covered with a small bandage. The test generally takes only a few minutes.
Risks and side effects of a potassium test are the same as for any routine blood test. In some cases, your health care provider may have trouble entering a suitable vein. In rare instances, people report:
Anytime the skin is broken, you also run a small risk of infection.
Your body needs potassium to function normally. It’s vital to the functioning of nerve and muscle cells. A normal potassium level is between 3.6 and 5.2 millimoles per liter. It’s important to note that individual laboratories may use different values. For that reason, you should ask your doctor to interpret your specific results.
The amount of potassium in your blood is so small that tiny increases or decreases can cause serious problems.
Lower-than-normal levels of potassium can be due to:
A blood potassium level of 7.0 millimoles per liter or higher can be life threatening. Having higher-than-normal levels of potassium in your blood can be the result of a variety of conditions and circumstances. These include:
False results of a potassium test can occur during the collection and processing of the blood sample. For example, your potassium levels may rise if you relax and clench your fist while blood is being collected. A delay in transporting the sample to the laboratory or shaking the sample may cause potassium to leak out of the cells and into the serum.
If your doctor suspects a false result, they may need to have you repeat the test.
You should be able to get the right amount of potassium from your diet. How much potassium you should take depends on your age, gender, and specific health conditions. Some excellent dietary sources of potassium are:
Written by: Ann Pietrangelo
Medically reviewed on: Nov 14, 2016: Deborah Weatherspoon, Ph.D, MSN, RN, CRNA
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