transtubular_potassium_gradient_guideline v.1
The transtubular potassium gradient (TTKG) is an index of the potassium (K) secretory process activity. TTKG facilitates the differential diagnosis between hyperkalemia and hypokalemia.
To record the transtubular potassium gradient (TTKG) in patients.
Use to record the transtubular potassium concentration gradient (TTKG) in patients with hyper- or hypokalemia. The TTKG formula is: (urine potassium / serum potassium) / (urine osmolality / serum osmolality). Urine sodium should be at least 25 mmol/L for this formula to be accurate. The expected TTKG values in healthy subjects (normal diet and no medication) are between 8 and 9. TTKG > 10 suggests normal renal excretion of potassium in patients with hyperkalemia (K⁺ >5.0 mEq/L). TTKG < 7 suggests hypoaldosteronism in patients with hyperkalemia. TTKG > 3 suggests renal potassium wasting in patients with hypokalemia (K⁺ <3.5 mEq/L).
Use only in patients with hyper- or hypokalemia.
Ethier JH, Kamel KS, Magner PO, Lemann J Jr, Halperin ML. The transtubular potassium concentration in patients with hypokalemia and hyperkalemia. Am J Kidney Dis. 1990 Apr;15(4):309-15. doi: 10.1016/s0272-6386(12)80076-x. PMID: 2321642. Joo KW, Chang SH, Lee JG, Na KY, Kim YS, Ahn C, Han JS, Kim S, Lee JS. Transtubular potassium concentration gradient (TTKG) and urine ammonium in differential diagnosis of hypokalemia. J Nephrol. 2000 Mar-Apr;13(2):120-5. PMID: 10858974. Choi MJ, Ziyadeh FN. The utility of the transtubular potassium gradient in the evaluation of hyperkalemia. J Am Soc Nephrol. 2008 Mar;19(3):424-6. doi: 10.1681/ASN.2007091017. Epub 2008 Jan 23. PMID: 18216310.
openEHR-EHR-OBSERVATION.transtubular_potassium_gradient, openEHR-EHR-OBSERVATION.blood_serum, openEHR-EHR-OBSERVATION.lab_test_serum_potassium, openEHR-EHR-OBSERVATION.lab_test-urea_and_electrolytes, openEHR-EHR-EVALUATION.transtubular_potassium_gradient_assessment
