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Potassium 24 hr Urine

Order Code U009
Turnaround Time 24-48 hours
Test Includes

Urinary excretion of potassium is increased in primary aldosteronism. It is often increased in dehydration and in salicylate toxicity. Decreased levels are seen in malabsorption.

Specimen Requirements
Specimen Source
Transport Container
(Specimen Container)

24-hour urine container

Preferred Specimens
Collection Instructions
(Transport Temperature)
Transport at Room Temperature
Specimen Stability
Temperature Period
Room temperature 14 days
Refrigerated 14 days
Frozen 30 days
Special Instructions

10 mL aliquot of a 24-hour urine collected in a no preservative plastic urine container . Record total volume and collection duration on specimen container and test requisition

Test Details
Ion Selective Electrode (ISE)
Clinical Significance

Potassium (K+) is the major intracellular cation. Functions of potassium include regulation of neuromuscular excitability, heart contractility, intracellular fluid volume, and hydrogen ion concentration. The physiologic function of K+ requires that the body maintain a low extracellular fluid (ECF) concentration of the cation; the intracellular concentration is 20 times greater than the extracellular K+ concentration. Only 2% of total body K+ circulates in the plasma.The kidneys provide the most important regulation of K+. The proximal tubules reabsorb almost all the filtered K+. Under the influence of aldosterone, the remaining K+ can then be secreted into the urine in exchange for sodium in both the collecting ducts and the distal tubules. Thus, the distal nephron is the principal determinant of urinary K+ excretion.Decreased excretion of K+ in acute renal disease and end-stage renal failure are common causes of prolonged hyperkalemia.Renal losses of K+ may occur during the diuretic (recovery) phase of acute tubular necrosis, during administration of nonpotassium sparing.

Reference Ranges

22 – 160 mmol/24 hr