What is potassium?
Potassium (K+) helps nerves and muscles communicate. It also helps move nutrients into cells and waste products out of cells.
Potassium, an essential nutrient found throughout the body, is necessary for healthy cell activity.
Potassium is also important in how nerves and muscles work.
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.
Potassium is also considered a mineral. It helps keep the water (the amount of fluid inside and outside the body's cells) and electrolyte balance of the body.
What is a blood potassium test?
A blood potassium test is one of the most commonly ordered lab tests and may be done for a wide variety of medical conditions. As an electrolyte that is critical in muscle contraction and nerve conduction, both elevated and decreased levels can be very serious.
Blood levels of potassium are frequently measured in a panel test along with other electrolytes, including sodium, chloride, and bicarbonate.
Your doctor may order a potassium test if they suspect you have an electrolyte imbalance or as part of a routine checkup.
A potassium test is performed as a simple blood test and carries few risks or side effects. The blood sample drawn will be sent to a laboratory for analysis.
In general, the potassium marker is part of a larger test panel called a Comprehensive Metabolic Panel (CMP).
Why is a potassium test performed?
Where do I get potassium in the diet?
Many foods are rich in potassium. A balanced diet has enough potassium for the body's needs. Some people also obtain potassium from dietary supplements.
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:
Swiss chard, lima beans, kidney beans, sweet potatoes, white potatoes (especially the skins), spinach, papaya, pinto beans, bananas, lentils.
What is a “normal” level of potassium in blood?
For most people, the level of potassium in your blood should be between 3.5 and 5.0, depending on the laboratory that is used. Ask your healthcare provider what your potassium level is. The results are reported in milli-equivalents per liter (mEq/l).
The reference range for a normal potassium can vary somewhat between labs, but is most often in the range of:
For adults: 3.5 mEq/l to 5.0 mEq/l
For children: 3.4 mEq/l to 4.7 mEq/l
For infants: 4.1 mEq/l to 5.3 mEq/l
For newborns: 3.9 mEq/l to 5.9 m Eq/l
Potassium in the body:
Under normal circumstances, your body absorbs and stores the potassium it needs, and the kidneys primarily remove any excess through urine. In this way, a potassium measurement can detect disruptions to how the body stores, uses, and excretes potassium.
Urine potassium tests together with creatinine:
In some urine potassium tests, creatinine is measured along with potassium. A waste material that is a byproduct of muscle activity, creatinine is excreted at a relatively steady pace daily. Simultaneous measuring urine creatinine normalizes the potassium excretion, independent of how many fluids you consume before the test and how diluted your urine is, without having to do a full 24-hour urine collection.
Why do potassium levels change?
Potassium levels often change with sodium levels. When sodium levels go up, potassium levels go down, and when sodium levels go down, potassium levels go up. Potassium levels are also affected by a hormone called aldosterone, which is made by the adrenal glands.
Aldosterone is a hormone that helps regulate your blood pressure by managing the levels of sodium (salt) and potassium in your blood and impacting blood volume. Having too much or too little aldosterone in your body can cause health issues.
Potassium levels can be affected by how the kidneys are working, the blood pH, the amount of potassium you eat, the hormone levels in your body, severe vomiting, and taking certain medicines, such as diuretics and potassium supplements. Certain cancer treatments that destroy cancer cells can also make potassium levels high.
But if your potassium levels get low, it can take some time for your body to start holding on to potassium. In the meantime, potassium is still passed in the urine, so you may end up with very low levels of potassium in your body, which can be dangerous.
A potassium level that is too high or too low can be serious. Abnormal potassium levels may cause symptoms such as muscle cramps or weakness, nausea, diarrhea, frequent urination, dehydration, low blood pressure, confusion, irritability, paralysis, and changes in heart rhythm.
Other electrolytes, such as sodium, calcium, chloride, magnesium, and phosphate, may be checked in a blood sample at the same time as a blood test for potassium.
References:
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Hypokalemia means low blood potassium levels. Your body needs potassium to function correctly.
Too little potassium in the blood is known as hypokalemia. Hypokalemia most often can happen after taking diuretic medications that increase urination. Diarrhea, vomiting, and profuse sweating may also cause fluid loss that diminishes blood levels of potassium. Less often, hypokalemia results from insufficient potassium intake due to poor diet or health conditions that increase the amount of potassium stored in cells.
Normal levels of potassium for an adult range from 3.5 to 5.2 mEq/L (3.5 to 5.2 mmol/L). Anything lower than 3 mEq/L (3 mmol/L) may be considered severe hypokalemia.
How does hypokalemia affect my body?
You need potassium to keep your muscles, nerves and heart working well. You also need potassium for a healthy digestive system and bone health. Low levels of potassium can affect these important functions in your body. Over time, low levels of potassium in your body can cause effects such as abnormal heart rhythms, muscle weakness and even paralysis.
What causes hypokalemia?
Low blood potassium typically occurs because of an excessive loss of potassium in your digestive tract. This may be due to frequent vomiting, diarrhea or laxative use.
Other causes of hypokalemia include:
What are the symptoms of hypokalemia?
Mild cases of low potassium may not cause any symptoms. But signs may include:
More severe cases of low potassium may cause signs and symptoms such as:
How is hypokalemia diagnosed?
Your healthcare provider will check your potassium level through a blood test. The normal potassium level for an adult ranges from 3.5 to 5.2 mEq/L (3.5 to 5.2 mmol/L). Potassium levels between 3 and 3.5 mEq/L (3 to 3.5 mmol/L) are considered mild hypokalemia. Anything lower than 3 mEq/L (3 mmol/L) is considered severe hypokalemia.
Your healthcare provider may also order a basic or comprehensive metabolic panel. This panel is a group of blood tests that determine your body's kidney function and electrolyte balance.
If hypokalemia is confirmed, your healthcare provider will try to determine the cause. If the cause isn’t clear, they may order a urine test (urinalysis) to measure the amount of potassium in your urine.
Your healthcare provider may also order an electrocardiogram (ECG or EKG). An ECG measures your heart rhythm. Hypokalemia can cause abnormal heart rhythms. An ECG can pick up the abnormal heart rhythms.
How is hypokalemia treated?
If you have a mild case of hypokalemia, your healthcare provider will prescribe a potassium supplement that you’ll take by mouth. If your case is more severe, your healthcare provider may give you potassium through your vein (intravenously). Reasons you may need potassium through your vein include:
Your healthcare provider will also treat any condition that’s causing hypokalemia.
If you need to take a diuretic, your healthcare provider may switch you to a type that keeps potassium in your body. They may also tell you to take extra potassium supplements.
How can I reduce my risk of hypokalemia?
You can reduce your risk of developing hypokalemia by eating a diet full of foods that contain potassium. Discuss your diet with your healthcare provider. Foods that have lots of potassium include:
What can I expect if I have hypokalemia?
If you have a mild case of hypokalemia, potassium supplements should help treat it. Make sure to continue eating a diet rich in potassium.
If your case is more severe, potassium given through your vein should treat it. If left untreated, severe hypokalemia can cause serious heart rhythm problems. In addition, life-threatening paralysis may occur.
Be sure to follow up with your healthcare provider to ensure that your hypokalemia is treated appropriately.
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Too much potassium in the blood is called hyperkalemia. This can signify that the kidneys are not properly removing excess potassium from the blood and excreting it from the body in urine. It is often related to certain medications that prevent the kidneys from regulating potassium levels, but other kidney disorders (such as acute or chronic kidney failure) may also cause it.
High blood potassium levels may be caused by damage or injury to the kidneys. This prevents the kidneys from removing potassium from the blood normally. High blood potassium levels can also be caused by conditions that move potassium from the body's cells into the blood. These conditions include:
Taking too many potassium supplements can also cause high levels of potassium in the blood.
Too much acid (pH) in the blood makes potassium levels higher by causing the potassium in the body's cells to "leak" out of cells and into the blood.
Some medicines, such as aldosterone antagonists and angiotensin-converting enzyme (ACE) inhibitors, can cause high potassium levels.
High potassium levels can also occur when too much potassium is released into the blood from inside cells where it is normally stored. This can be caused by burns or other injuries (eg, severe tissue trauma, hemolysis), and conditions that affect the acid-base balance in the body.
In many cases, high potassium levels are the result of multiple causes. Increasing potassium intake from diet or supplements rarely causes hyperkalemia alone. Still, when paired with reduced kidney function or other contributing factors, increased intake may spur a rise in blood levels of potassium.
False hyperkalemia may occur if blood samples are not collected and handled properly. For example, if red cells are destroyed during the collection procedure.
The most common causes of hyperkalemia include:
Kidney Disease:
Hyperkalemia can happen if your kidneys do not work well. It is the job of the kidneys to balance the amount of potassium taken in with the amount lost in urine. Potassium is taken in through the foods you eat and the liquids you drink. It is filtered by the kidneys and lost through the urine. In the early stages of kidney disease, the kidneys can often make up for high potassium. But as kidney function gets worse, they may not be able to remove enough potassium from your body. Advanced kidney disease is a common cause of hyperkalemia.
A diet high in potassium:
Eating too much food that is high in potassium can also cause hyperkalemia, especially in people with advanced kidney disease. Foods such as cantaloupe, honeydew melon, orange juice, and bananas are high in potassium.
Drugs that prevent the kidneys from losing enough potassium:
Some drugs can keep your kidneys from removing enough potassium. This can cause your potassium levels to rise.
Other (less common) causes include:
What are the symptoms of hyperkalemia?
Many people have few, if any, symptoms. If symptoms do appear, they are usually mild and non-specific. You may feel some muscle weakness, numbness, tingling, nausea, or other unusual feelings. It usually develops slowly over many weeks or months and is often mild. It can recur.
If hyperkalemia comes on suddenly and you have very high levels of potassium, you may feel heart palpitations, shortness of breath, chest pain, nausea, or vomiting. Sudden or severe hyperkalemia is a life-threatening condition. It requires immediate medical care.
How to treat hyperkalemia?
If you have hyperkalemia—or if you are at risk for getting it— you may need to follow a low-potassium diet. Ask your healthcare provider or dietitian how much potassium is right for you. Eating too much can be harmful, but having too little can cause problems, too. Some people may need a little more; others may need less. High protein foods such as meat, fish, and chicken also have potassium, but you need a balance of high protein foods to stay healthy. Portion size is very important. A dietitian can help you create a meal plan that gives you the right amount of potassium and protein to meet your needs.
Here are a few tips:
Follow a low-potassium diet, if needed. Eating too much food that is high in potassium can cause problems in some people, especially in people with kidney disease. Ask your healthcare provider or dietitian how much potassium is right for you. Eating too much can be harmful, but having too little can cause problems, too. Some people may need a little more; others may need less.
Try avoiding certain salt substitutes. Certain salt substitutes are high in potassium. Most people with kidney disease should not use them.
Avoid herbal remedies or supplements. They may have ingredients that can raise potassium levels. In general, people with kidney disease should not take herbal supplements. If you have any questions about them, ask your healthcare provider.
Taking water pills or potassium binders, as directed by your healthcare provider. Some people may also need medicine to help remove extra potassium from the body and keep it from coming back. This may include:
Follow your treatment plan carefully if you have diabetes, kidney disease, heart disease, or any other serious condition. Following your treatment plan will help you keep your potassium levels in the healthy range.
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Alanine-aminotransferase (ALT, SGPT), Albumin, Serum, Albumin/Globulin (A/G) Ratio, Alkaline Phosphatase (ALP), Aspartate-aminotransferase (AST, SGOT), Bilirubin Total, Blood urea nitrogen (BUN), BUN/Creatinine Ratio, Calcium, Serum, Carbon Dioxide (CO2), Chloride, Serum, Creatinine, Serum, eGFR - Estimated Glomerular Filtration Rate (African Am), eGFR - Estimated Glomerular Filtration Rate (Non-African Am), eGFR / Cystatin C, Globulin, Serum (aka Globulin, Total), Glucose, Glucose Non-Fasting, Intestinal Isoenzymes (Alkaline Phosphatase), Potassium, Serum (Kalium), Sodium, Serum (Natrium), Total Protein, Serum