What is the role of 24-hour urine potassium excretion measurement in the diagnosis of hypokalemia (low potassium level)?

Updated: Dec 06, 2018
  • Author: Eleanor Lederer, MD, FASN; Chief Editor: Vecihi Batuman, MD, FASN  more...
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While more cumbersome to obtain, a 24-hour urine measurement of potassium excretion yields more precise data on how much potassium is being lost through renal excretion. Because the kidneys can conserve up to approximately 10-15 mEq of potassium per day, a value of less than 20 mEq on a 24-hour urine specimen suggests appropriate renal conservation of potassium, while values above that indicate some degree of renal wasting. To ensure that a full and accurate 24-hour urine sample has been collected, urine creatinine should be measured simultaneously.

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