Urine anion gap
Separates renal from extrarenal causes of normal anion gap metabolic acidosis.
Inputs
0 of 3mEq/L
mEq/L
mEq/L
When to use
- Hyperchloremic (normal anion gap) metabolic acidosis.
Pearls and pitfalls
- Negative (more ammonium excreted): GI losses such as diarrhea. Positive: renal tubular acidosis.
- Unreliable with ketonuria, very low urine sodium (below 20), or high urine pH.
Why use
A cheap estimate of urinary ammonium.
Urine AG = urine Na + urine K − urine Cl