Spurious
- Leakage from erythrocytes, marked thrombocytosis or leukocytosis
- Repeated fist clenching during phlebotomy
- Specimen from arm with K+ infusion
Decreased excretion
- Renal failure
- Renal secretory defects, eg, interstitial nephritis, sickle cell disease
- Hypoaldosteronism: hyporeninism (type IV renal tubular acidosis), eg, diabetic nephropathy, heparin, AIDS; adrenal insufficiency
- Drugs that inhibit K+ excretion (spironolactone, triamterene, ACE inhibitors, trimethoprim, NSAIDs)
Potassium shift out of cell
- Burns, rhabdomyolysis, hemolysis, severe infection, internal bleeding, vigorous exercise
- Metabolic acidosis
- Hypertonicity (solvent drag)
- Insulin deficiency
- Hyperkalemic periodic paralysis
- Drugs: digitalis toxicity, beta-adrenergic antagonists, succinylcholine, arginine
Excessive intake of K+