This, in turn, causes inadequate secretion of protons and potassium, with decreased trapping and excretion of ammonium and decreased excretion of potassium.
[emedicine.medscape.com]
In five patients, impaired potassium excretion was associated with decreased ammonium excretion, a urinary pH below 5.5 (5.18±0.07, mean ±S.E.M.), and aldosterone deficiency
[nejm.org]
Type 4 RTA is confirmed by a history of a condition that could be associated with type 4 RTA, chronically elevated potassium, and normal or mildly decreased bicarbonate.
[merckmanuals.com]