Nephrology · Internal Medicine

Transtubular Potassium Gradient (TTKG) calculator

Enter the published formula inputs below to calculate and interpret this score.

Clinical inputs

Urine potassium (mmol/L)

Serum potassium (mmol/L)

Urine osmolality (mOsm/kg)

Serum osmolality (mOsm/kg)

Result

Complete all required inputs to calculate the score.

Formula inputs

Urine potassium (mmol/L)Accepted range: 1 to 200
Serum potassium (mmol/L)Accepted range: 1 to 10
Urine osmolality (mOsm/kg)Accepted range: 50 to 1200
Serum osmolality (mOsm/kg)Accepted range: 250 to 350

Primary source

West ML et al. New clinical approach to evaluate disorders of potassium excretion. Miner Electrolyte Metab. DOI: 10.1159/000150253. PMID: 3952604. Scope: transtubular potassium gradient (TTKG) = (urine K × serum osmolality) / (serum K × urine osmolality) when urine is at least iso-osmolar to plasma. (1986)

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