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Transtubular Potassium Gradient Calculation

Transtubular potassium gradient (TTKG) is an index reflecting the conservation of potassium in the cortical collecting ducts of the kidneys. It is useful in diagnosing the cause of hyperkalemia.

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Transtubular Potassium Gradient (TTKG) Calculator

Urine K (mmol/L)
TPlasma osmolality (mmol/kg)
Plasma K (mmol/L)
Urine osmolality (mmol/kg)
TTKG =

 
   
  



Formula Used:

TTKG = (Urine K * Plasmaosm) / (Plasma K *Urineosm)

Where,

TTKG = Transtubular Potassium Gradient
Urine K = Urine potassium (in mEq/L or mmol/L)
Plasma K = Plasma potassium (in mEq/L or mmol/L)
Plasmaosm = Plasma osmolality (in mOsm/kg or mmol/kg)
Urineosm = Urine osmolality (in mOsm/kg or mmol/kg)

During potassium depletion or hypokalemia, the TTKG should fall to less than 3, indicating appropriately reduced urinary excretion of potassium. Free online Medical Calculators.