Potassium Test: Normal Levels, Causes of Low and High Potassium

A potassium test is a blood test that measures the level of potassium in the blood. There is little potassium in the blood, and the majority is in cells. Raised or lowered levels of blood potassium can have an effect on the heart, nerves, and muscles, even though they might very well be small. The test is often ordered as part of a group of lab tests called an electrolyte panel or a complete metabolic panel. It can also be used on its own to track those with kidney disease, people on some medications, or any person who is having symptoms of an electrolyte disorder.

Why Is a Potassium Blood Test Important?

Potassium helps generate the electrical signals that control muscle contraction and nerve communication. It also helps in keeping the body's internal fluid balance in check and helps in keeping the rhythm regular in the heart. Your doctor might order your potassium level checked in your blood to be sure it's normal. Kidney disease, dehydration, some medications, hormone imbalance, or other medical problems can cause abnormal levels of potassium. This test might be ordered if a person has symptoms of an electrolyte imbalance or muscle weakness and tiredness, or if symptoms of irregular heartbeat. It may also be useful for people with kidney disease and those who take certain medicines that may deplete potassium.

What Are the Normal Potassium Levels?

In normal blood, potassium is within the range of 3.5 to 5.0 milliequivalents per litre (mEq/L). The reference range is a little different, depending on the lab and testing equipment. When the potassium level is low, it is referred to as Hypokalaemia; when the level is high, it is Hyperkalaemia. Results should be interpreted by a healthcare professional together with symptoms, medical history, medications, and other tests. 

Causes of Low Potassium Levels

Hypokalaemia (low potassium) is when the level of potassium is lower than normal in the blood. Hypokalaemia occurs when the body loses excessive amounts of potassium and/or fails to absorb or retain sufficient amounts of potassium, or when potassium goes into the cells. It's typically due to vomiting or diarrhea that results in a deficit of potassium. Profuse sweating, especially if there is not enough fluid intake and electrolyte replenishment, may be a factor in electrolyte abnormalities.

Some medicines may cause you to pass potassium in your urine, including diuretics to help your blood pressure or fluid retention. It may also be unable to maintain the balance of potassium in your blood due to other kidney and/or hormone problems. Mildly low potassium may not cause symptoms. In severe deficiency, muscles cramp and become weak, constipation occurs, fatigue sets in, and abnormal heart rhythms can occur. The treatment is based on the severity and cause of hypokalaemia. Potassium replacement may be prescribed by a doctor when required. 

Causes of High Potassium Levels

Hyperkalaemia is a high blood potassium level, that is, one that is greater than the normal range. Hyperkalaemia can develop if the kidneys have difficulty getting rid of excess potassium from the body, and/or when potassium moves out of cells and into the blood. It is more common in people with kidney disease, because the kidneys normally remove excess potassium. Other medications may also cause too much potassium to build up in the blood, such as some blood pressure medicines and potassium-sparing diuretics, which help to retain potassium in the blood.

Other factors can include metabolic disorders, severe tissue damage, and some hormonal diseases. In addition, when affected, severe dehydration could play a role. False high blood test results could be the result of hemolysis (bursting) of blood cells during collection or processing. This is called pseudohyperkalaemia. If the doctor doesn't think the patient matches up with the test result, he may recommend that the test be repeated. In some cases, no signs or symptoms are associated with high potassium. When symptoms do develop, they can include muscle weakness, tingling, nausea, and an abnormal heartbeat. Life-threatening heart rhythm abnormalities can occur if hyperkalaemia is severe and is an emergency and requires urgent medical assessment.

How Is the Potassium Test Performed?

A blood test is taken (usually from a vein in the arm) to check the blood potassium levels. The health care worker cleans the area, inserts a tiny needle, and withdraws a sample of blood into a blood collection tube. The collected blood sample is sent to the laboratory for analysis. Generally, no preparation is recommended for the test. However, one should follow the instructions from one's doctor or Diagnostic Laboratory. You should let your health care provider know about any medication or supplements you are taking because some may affect the levels of potassium in your body. Don't stop prescribed medicine unless directed to do so by a doctor.

Conclusion

Molecular Diagnostics and Therapy offers all kinds of diagnostic testing to assess and monitor health issues. The potassium test helps assess electrolyte balance in the body and aids in the evaluation and monitoring of conditions that could impact blood Potassium levels. Test results must be used in conjunction with the clinical picture, history, and other test results with a competent health care worker. A blood potassium test may be used to help determine if levels are okay or not and to help determine if any further investigation or treatment is needed.