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Test ID: PHU_ pH, Random, Urine

Reporting Name

pH, U

Useful For

Assessment of patients with metabolic acidosis


Assessment of crystalluria


Monitoring the effectiveness of alkalinization or acidification of urine for certain medical conditions (eg, treatment of uric acid nephrolithiasis)

Clinical Information

Urine pH is a measure of the acidity/alkalinity of urine, and by itself usually provides little useful information. Under normal conditions its value is influenced by the type of diet (some diets: eg, diets rich in meat-having more acid content than others; eg, vegetarian diets). Assessment of urine pH may be useful in the evaluation of systemic acid-base disorder. For example, the normal response during metabolic acidosis is a lowering of the urine pH to less than 5. If it is >5, then a defect in urine acidification should be considered. Often a urine pH above 7 is suggestive of infection of a urea splitting organism such as proteus mirabilis. Monitoring of urine pH may also be helpful during therapeutic interventions to either alkalinize the urine (such as for treatment of uric acid nephrolithiasis) or acidify the urine. Finally, when assessing crystalluria, noting the urine pH may be helpful since some crystals have a propensity to form in alkaline urine while others form in relative acidic urine.


Dependent on clinical condition.

Analytic Time

1 day

Day(s) and Time(s) Performed

Monday through Sunday; Continuously

Method Name

pH meter

Specimen Type


Specimen Required

Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 10 mL

Collections Instructions: Collect a random urine specimen.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 7 days
  Frozen  7 days

Reference Values


Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
PHU_ pH, U 2756-5


Result ID Test Result Name Result LOINC Value
PHU_ pH, U 2756-5
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