A fresh, early morning sample is preferred.
The measurement of urine pH can be helpful in the assessment of patients with renal tubular acidosis (RTA) and in stone formers. The finding of a urine pH >5.5 in the presence of systemic acidosis supports the diagnosis of RTA.
No reference range is reported for urine pH. Although urine pH normally ranges between 6.5 to 8.5 in healthy individuals, it varies with food consumption. Urine with a pH >6.0 is suggestive of alkali contamination or the presence of urea splitting bacteria. In a patient with metabolic acidosis, a urine pH >5.5 suggests a failure of urinary acidification which may indicate renal tubular acidosis.