| Spurious/Pseudohyperkalemia Leakage from erythrocytes when separation of serum from clot is delayed (plasma K+ normal) Marked thrombocytosis or leukocytosis with release of intracellular K+ (plasma K+ normal) Repeated fist clenching during phlebotomy, with release of K+ from forearm muscles Specimen drawn from arm with intravenous K+ infusion Decreased K+ excretion Kidney disease, acute and chronic Renal secretory defects (may or may not have reduced kidney function): kidney transplant, interstitial nephritis, systemic lupus erythematosus, sickle cell disease, amyloidosis, obstructive nephropathy Hypoaldosteronism Addison disease Type IV renal tubular acidosis Heparin Drugs that inhibit potassium excretion: spironolactone, eplerenone, drospirenone, NSAIDs, ACE inhibitors, angiotensin II receptor blockers, triamterene, amiloride, trimethoprim, pentamidine, cyclosporine, tacrolimus Shift of K+ from within the cell Massive release of intracellular K+ in burns, rhabdomyolysis, hemolysis, severe infection, internal bleeding, vigorous exercise Metabolic acidosis (in the case of organic acid accumulation— eg, lactic acidosis—a shift of K+ does not occur since organic acid can easily move across the cell membrane) Hypertonicity (solvent drag) Insulin deficiency (metabolic acidosis may not be apparent) Hyperkalemic periodic paralysis Drugs: succinylcholine, arginine, digitalis toxicity, beta-adrenergic antagonists Alpha-adrenergic stimulation? Excessive intake of K+ Especially in patients taking medications that decrease potassium secretion (see above) |