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Potassium Blood Test

What is a potassium blood test?

A potassium blood test measures the amount of potassium in your blood. Potassium is a type of electrolyte. Electrolytes are electrically charged minerals in your body that help control muscle and nerve activity, maintain fluid levels, and perform other important functions. Your body needs potassium to help your heart and muscles work properly. Potassium levels that are too high or too low may indicate a medical problem.

Other names: potassium serum, serum potassium, serum electrolytes, K

What is it used for?

A potassium blood test is often included in a series of routine blood tests called an electrolyte panel. The test may also be used to monitor or diagnose conditions related to abnormal potassium levels. These conditions include kidney disease, high blood pressure, and heart disease.

Why do I need a potassium blood test?

Your health care provider may order a potassium blood test as part of your regular checkup or to monitor an existing condition such as diabetes or kidney disease. You may also need this test if you have symptoms of having too much or too little potassium.

If your potassium levels are too high, your symptoms may include:

  • Irregular heart rhythms
  • Fatigue
  • Weakness
  • Nausea
  • Paralysis in the arms and legs

If your potassium levels are too low, your symptoms may include:

  • Irregular heart rhythms
  • Muscle cramps
  • Twitches
  • Weakness
  • Fatigue
  • Nausea
  • Constipation

What happens during a potassium blood test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

See also  Insulin in Blood

Will I need to do anything to prepare for the test?

You don’t need any special preparations for a potassium blood test or an electrolyte panel. If your health care provider has ordered more tests on your blood sample, you may need to fast (not eat or drink) for several hours before the test. Your health care provider will let you know if there are any special instructions to follow.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Too much potassium in the blood, a condition known as hyperkalemia, may indicate:

  • Kidney disease
  • Burns or other traumatic injuries
  • Addison’s disease, a hormonal disorder that can cause a variety of symptoms including weakness, dizziness, weight loss, and dehydration
  • Type 1 diabetes
  • The effect of medicines, such as diuretics or antibiotics
  • In a rare instance, a diet too high in potassium. Potassium is found in many foods, such as bananas, apricots, and avocados, and is part of a healthy diet. But eating excessive amounts of potassium-rich foods can lead to health problems.

Too little potassium in the blood, a condition known as hypokalemia, may indicate:

  • A diet too low in potassium
  • Alcoholism
  • Loss of bodily fluids from diarrhoea, vomiting, or use of diuretics
  • Aldosteronism, a hormonal disorder that causes high blood pressure

If your results are not in the normal range, it doesn’t necessarily mean that you have a medical condition requiring treatment. Certain prescription and over-the-counter medicines may raise your potassium levels, while eating a lot of licorice may lower your levels. To learn what your results mean, talk to your health care provider.

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Is there anything else I need to know about a potassium blood test?

Repeated clenching and relaxing of your fist just before or during your blood test may temporarily increase the potassium levels in your blood. This may lead to an incorrect result.

References

  1. Hinkle J, Cheever K. Brunner & Suddarth’s Handbook of Laboratory and Diagnostic Tests. 2nd Ed, Kindle. Philadelphia: Wolters Kluwer Health, Lippincott Williams & Wilkins; c2014. Potassium, Serum; 426–27 p.
  2. Lab Tests Online [Internet]. Washington D.C.: American Association for Clinical Chemistry; c2001–2017. Potassium [updated 2016 Jan 29; cited 2017 Feb 8]; [about 2 screens]. Available from: https://labtestsonline.org/understanding/analytes/potassium/tab/test
  3. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2017. High potassium (hyperkalemia); 2014 Nov 25 [cited 2017 Feb 8]; [about 4 screens]. Available from: http://www.mayoclinic.org/symptoms/hyperkalemia/basics/when-to-see-doctor/sym-20050776
  4. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2017. Low potassium (hypokalemia); 2014 Jul 8 [cited 2017 Feb 8]; [about 4 screens]. Available from: http://www.mayoclinic.org/symptoms/low-potassium/basics/when-to-see-doctor/sym-20050632
  5. Mayo Clinic [Internet]. Mayo Foundation for Medical Education and Research; c1998–2017. Primary aldosteronism; 2016 Nov 2 [cited 2017 Feb 8]; [about 3 screens]. Available from: http://www.mayoclinic.org/diseases-conditions/primary-aldosteronism/home/ovc-20262038
  6. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2016. Addison Disease (Addison’s Disease; Primary or Chronic Adrenocortical Insufficiency) [cited 2017 Feb 8]; [about 3 screens]. Available from: https://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/adrenal-gland-disorders/addison-disease
  7. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2016. Hyperkalemia (High Level of Potassium in the Blood) [cited 2017 Feb 8]; [about 3 screens]. Available from: http://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/hyperkalemia-high-level-of-potassium-in-the-blood
  8. Merck Manual Consumer Version [Internet]. Kenilworth (NJ): Merck & Co., Inc.; c2016. Hypokalemia (Low Level of Potassium in the Blood) [cited 2017 Feb 8]; [about 3 screens]. Available from: http://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/hypokalemia-low-level-of-potassium-in-the-blood
  9. Merck Manual Consumer Version [Internet]. Kenilworth (NJ Merck & Co., Inc.; c2016. Overview of Potassium’s Role in the Body [cited 2017 Feb 8]; [about 3 screens]. Available from: http://www.merckmanuals.com/home/hormonal-and-metabolic-disorders/electrolyte-balance/overview-of-potassium-s-role-in-the-body
  10. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What Are the Risks of Blood Tests? [updated 2012 Jan 6; cited 2017 Feb 8]; [about 4 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests#Risk-Factors
  11. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; What To Expect with Blood Tests [updated 2012 Jan 6; cited 2017 Feb 8]; [about 4 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests
  12. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Types of Blood Tests [updated 2012 Jan 6; cited 2017 Feb 8]; [about 4 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests#Types
  13. National Kidney Foundation [Internet]. New York: National Kidney Foundation Inc., c2016. A to Z Health Guide: Understanding Lab Values [updated 2017 Feb 2; cited 2017 Feb 8]; [about 2 screens]. Available from: https://www.kidney.org/kidneydisease/understandinglabvalues
  14. National Kidney Foundation [Internet]. New York: National Kidney Foundation Inc., c2016. Potassium and Your CKD Diet [cited 2017 Feb 8]; [about 2 screens]. Available from: https://www.kidney.org/atoz/content/potassium
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