Potassium test

Alternative names:

hypokalemia test; K+

What the risks are:

Risks associated with venipuncture are slight:

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

Special considerations:

Interfering factors:

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

Drugs that can increase potassium measurements include aminocaproic acid, antineoplastic drugs, captopril, 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 (see salicylates - oral), 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.