pH, urine
Clinical Background:
The pH of urine is determined by the need to maintain the blood pH within a tightly controlled range. Urine pH will therefore vary to maintain this control and is usually acidic because of the need...
The pH of urine is determined by the need to maintain the blood pH within a tightly controlled range. Urine pH will therefore vary to maintain this control and is usually acidic because of the need to excrete excess hydrogen ions. Normally acid base balance is assessed using blood markers such as pH and bicarbonate and treating the underlying cause. Urine pH measurement is only of use in the investigation of possible renal tubular acidosis when the urine is inappropriately alkaline for the degree of systemic metabolic acidosis.
Test Details
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Discipline:
Biochemistry
Biochemistry
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Specimen Container Adult:
Urine-Random
Urine-Random
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Specimen Container Paediatric:
Urine-Random
Urine-Random
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Minimum Volume Adult:
1 mL urine
1 mL urine
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Minimum Volume Paediatric:
1 mL urine
1 mL urine
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Special Requirement:
We recommend measuring urine pH on the ward using a point of care dipstick. If this is not possible, please send the sample to the laboratory as soon as it has been collected.
We recommend measuring urine pH on the ward using a point of care dipstick. If this is not possible, please send the sample to the laboratory as soon as it has been collected.
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Sample Stability:
Urine pH will alter with time due to mico-organism actions.
Urine pH will alter with time due to mico-organism actions.
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Interpretation:
On standing urine pH tends to rise due to formation of ammonia by micro-organisms. The pH of urine containing glucose may decrease as micro-organisms metabolise the glucose. Bacterial infections ca...
Read MoreOn standing urine pH tends to rise due to formation of ammonia by micro-organisms. The pH of urine containing glucose may decrease as micro-organisms metabolise the glucose. Bacterial infections can alter the pH in either direction.
In metabolic acidosis the urine pH should also be maximally acidic. A urine pH which is not at the lowest physiologically likely (pH 4.5) is likely to be inappropriately alkaline and consideration should be given to whether renal tubular acidosis is present. -
Reference Ranges:
Adult: 4.5 - 8.0
Adult: 4.5 - 8.0
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Routine Contact Name:
Duty biochemist
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Routine Telephone:
Freeman: 0191 244 8889
RVI: 0191 282 9719Freeman: 0191 244 8889
RVI: 0191 282 9719 -
Routine Email: