Positive Urinary Anion Gap helps to establish the diagnosis of :

Answer is C (Renal Tubular Acidosis):Positive Urinary Anion gap helps in establishing a diagnosis of Renal Tubular AcidosisUrinary Anion Gap (UAG) can be used to estimate renal ammonium production and distinguish Renal Tubular Acidosis (Positive UAG) from GI bicarbonate loss (Negative UAG)- HarrisonsUrinary Anion Gap (UAG)Urinary Anion Gap (UAG) calculation is useful in cases of Normal Anion Gap (Hyperchloremic) Metabolic AcidosisNormal Anion Gap Acidosis may result from excessive bicarbonate losses from either the gastrointestinal tract (eg diarrhea) or renal sources (eg Renal Tubular Acidosis)Urinary Anion Gap Estimation helps to distinguish Renal bicarbonate loss from Gastrointestinal bicarbonate loss thereby helping in establishing the cause of normal anion gap metabolic acidosisPositive Urinary Anion Gap:- Implies Renal loss of Bicarbonate and the diagnosis is usually distal A Negative Urinary Anion Gap:- Implies Gastrointestinal loss of BicarbonateNoteIn type II (Proximal A) the kidney has defective HCO3- reabsorption leading to increased HCO3- excretion rather than decreased NH4C1 excretion.Thus the urinary anion gap is often negative