🫘 Urine Anion Gap Calculator
Calculate the urine anion gap to evaluate normal-anion-gap metabolic acidosis.
Clinical takeaway
A surrogate for urinary ammonium.
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When to use
Distinguish renal tubular acidosis from extrarenal bicarbonate loss.
How it works
UAG = UNa + UK − UCl. Negative → appropriate NH₄⁺ excretion (GI loss); positive → impaired excretion (distal RTA).
Key points
- A surrogate for urinary ammonium.
- Unreliable with ketoacids or other unmeasured urinary anions.
- Interpret with serum acid–base and potassium.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Urine sodium | 40 mmol/L |
|---|---|
| Urine potassium | 30 mmol/L |
| Urine chloride | 60 mmol/L |
→Urine anion gap10mmol/L
- Interpretation：Positive — impaired renal NH₄⁺ excretion (e.g. distal RTA).
- Formula：UAG = UNa + UK − UCl
Frequently asked questions
- What is Urine Anion Gap Calculator?
- Calculate the urine anion gap to evaluate normal-anion-gap metabolic acidosis.
- How is Urine Anion Gap Calculator calculated? What is the core formula?
- UAG = UNa + UK − UCl. Negative → appropriate NH₄⁺ excretion (GI loss); positive → impaired excretion (distal RTA).
- When is Urine Anion Gap Calculator used?
- Distinguish renal tubular acidosis from extrarenal bicarbonate loss.
- What are the key clinical points for Urine Anion Gap Calculator?
- A surrogate for urinary ammonium. Unreliable with ketoacids or other unmeasured urinary anions. Interpret with serum acid–base and potassium.
- What are the limits and cautions when using Urine Anion Gap Calculator?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Urine Anion Gap Calculator calculated in practice? Can you show a worked example?
- Inputs: Urine sodium 40 mmol/L, Urine potassium 30 mmol/L, Urine chloride 60 mmol/L → Result: Urine anion gap 10 mmol/L（Interpretation: Positive — impaired renal NH₄⁺ excretion (e.g. distal RTA)., Formula: UAG = UNa + UK − UCl）