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Blood test
Blood test


Potassium test

Alternative Names:
Hypokalemia test; K+

What the risks are:

Risks associated with venipuncture are slight:

  • excessive bleeding
  • fainting or feeling light-headed
  • hematoma (blood accumulating under the skin)
  • infection (a slight risk any time the skin is broken)
  • multiple punctures to locate veins


Special considerations:

The following factors can interfere with the test:

  • Infusion of potassium-containing fluids
  • Infusion of glucose or insulin

Drugs that can increase potassium measurements include aminocaproic acid, antineoplastic drugs, ACE inhibitors (such as captopril or enalapril) epinephrine, heparin, histamine, isoniazid, mannitol, some diuretics, and succinylcholine.

Drugs that can decrease potassium measurements include acetazolamide, aminosalicylic acid, amphotericin B, carbenicillin, cisplatin, some diuretics, insulin, laxatives, penicillin G, phenothiazines, salicylates, and sodium polystyrene sulfonate.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others. If puncturing the vein is difficult, trauma to the red blood cells may cause potassium to be released from them, causing a falsely elevated result.




Review Date: 6/13/2005
Reviewed By: Nader Najafian, M.D., Associate Physician, Renal Division, Brigham & Women's Hospital, Instructor of Medicine, Harvard Medical School, Boston, MA. Review provided by VeriMed Healthcare Network.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2004 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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