Urine electrolyte levels

Further information: Urinary calcium

Urine electrolyte levels can be measured in a medical laboratory for diagnostic purposes. The urine concentrations of sodium, chlorine and potassium may be used to investigate conditions such as abnormal blood electrolyte levels, acute kidney injury, metabolic alkalosis and hypovolemia.[1][2][3] Other electrolytes that can be measured in urine are calcium, phosphorus and magnesium.[4]

Target Lower limit Upper limit Unit Comments LOINC Codes
Sodium (Na) – per day 150[5] 300[5] mmol / 24 h A sodium-related parameter is fractional sodium excretion, which is the percentage of the sodium filtered by the kidney which is excreted in the urine. It is a useful parameter in acute kidney failure and oliguria, with a value below 1% indicating a prerenal disease and a value above 1% suggesting acute tubular necrosis or other kidney damage.[6] 2956-1
Potassium (K) – per day 40[5] 90[5] mmol / 24 h Urine K may be measured in a diagnostic examination for hypokalemia (low blood potassium). If potassium is being lost through the kidneys, urine potassium will likely be high. If urine potassium is low, this suggests a non-renal cause.[7]
Urinary calcium (Ca) – per day 2.5 6.25 mmol / 24 h An abnormally high level is called hypercalciuria and an abnormally low rate is called hypocalciuria. 14637-3
100[8] 250[8] mg / 24 hours 6874-2
Phosphate (P) – per day n/a[5] 38[5] mmol / 24 h Phosphaturia is the hyperexcretion of phosphate in the urine. This condition is divided into primary and secondary types. Primary hyperphosphaturia is characterized by direct excess excretion of phosphate by the kidneys, as from primary kidney dysfunction, and also the direct action of many classes of diuretics on the kidneys. Additionally, secondary causes, including both types of hyperparathyroidism, cause hyperexcretion of phosphate in the urine.[citation needed] 14881-7
  1. ^ Reddi, A.S. (2014). Fluid, electrolyte, and acid-base disorders: clinical evaluation and management. Springer. pp. 13−4. ISBN 978-1-4614-9082-1.
  2. ^ Kamel, K.S.; Halperin, M.L. (2021). "Use of Urine Electrolytes and Urine Osmolality in the Clinical Diagnosis of Fluid, Electrolytes, and Acid-Base Disorders". Kidney International Reports. 6 (5): 1211–1224. doi:10.1016/j.ekir.2021.02.003. PMC 8116912. PMID 34013099. S2CID 233917331.
  3. ^ Umbrello, M.; Formenti, P.; Chiumello, D. (2020). "Urine Electrolytes in the Intensive Care Unit: From Pathophysiology to Clinical Practice". Anesthesia & Analgesia. 131 (5): 1456–1470. doi:10.1213/ANE.0000000000004994. PMID 33079869. S2CID 220414625.
  4. ^ Wu, X. (2010). "Urinalysis: A Review of Methods and Procedures". Critical Care Nursing Clinics of North America. 22 (1): 121–128. doi:10.1016/j.ccell.2009.10.012. PMID 20193886.
  5. ^ a b c d e f Reference range list from Uppsala University Hospital ("Laborationslista"). Artnr 40284 Sj74a. Issued on April 22, 2008
  6. ^ "MedlinePlus Medical Encyclopedia: Fractional excretion of sodium". Retrieved 11 July 2022.
  7. ^ Lederer, E. (8 January 2021). "Hypokalemia Workup". Medscape. Retrieved 11 June 2022.
  8. ^ a b medscape.com - Urine Calcium: Laboratory Measurement and Clinical Utility Archived 2011-09-06 at the Wayback Machine By Kevin F. Foley, PhD, DABCC; Lorenzo Boccuzzi, DO. Posted: 12/26/2010; Laboratory Medicine. 2010;41(11):683–686. © 2010 American Society for Clinical Pathology. In turn citing:
    • Wu HBA. Tietz Guide to Clinical Laboratory Tests. 4th ed. St. Louis, MO: Saunders, Elsevier; 2006.