Diagnosis of<unk>  is done by measuring the level of fractional excretion of bicarbonate in the urine. Since in<unk>  patients the nephron is unable to reabsorb bicarbonate, the level of bicarbonate is going to be high in the urine.
Proximal renal tubular acidosis
Distal renal tubular acidosis
Renal tubular acidosis
Inborn errors of renal tubular transport
Isotonic hyponatremia
Cystinuria
Hypotonic hyponatremia
Primary hyperoxaluria