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Transtubular Potassium Gradient at CCD   TTKG = (UrineK / SerumK) / (UrineOsm / SerumOsm)   Input:   Urine K   mEq/L Serum K   mEq/L Urine Osm   mOsm/dL mOsm/kg Serum Osm   mOsm/dL mOsm/kg Result:   TTKG   # index none number points score   Decimal Precision: 0 1 2 3           Notes The transtubular potassium gradient in the cortical collecting duct is an index reflecting conservation of potassium. A normal TTKG in normal subjects on normal diets is 8-9. With a potassium load the TTKG may rise to 11. In the face of Hyperkalemia, a low TTKG (< 7) may indicate hypoaldosteronism. Without other disease, hypokalemia should produce a TTKG < 3 (some authors say TTKG < 2.) The expected TTKG in hyperkalemia is > 10.   Related Results            Pull down to select a related equation and transfer values in common Osmolar Clearance     [ Urine_Osm, Serum_Osm ]       References West ML, Marsden PA, Richardson RM, et. al. New clinical approach to evaluate disorders of potassium excretion. Mineral Electrolyt Metab. 12:234,1986. Ethier JH, Kamel KS, Magner PO, et. al. The transtubular potassium concentration in patients with hypokalemia and hyperkalemia. Am J Kidney Dis. 15:309,1990.     Legal Notices and Disclaimer   All information contained in and produced by the MedCalc 3000 system is provided for educational purposes only. This information should not be used for the diagnosis or treatment of any health problem or disease. THIS INFORMATION IS NOT INTENDED TO REPLACE CLINICAL JUDGMENT OR GUIDE INDIVIDUAL PATIENT CARE IN ANY MANNER. Click here for full notice and disclaimer.   MedCalc 3000 is Copyright © 1998-2010 Foundation Internet Services, LLC    [Build 240921 v9.1]