Test Details
Methodology
Electrochemical (pH meter)
Result Turnaround Time
3 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Use
The urine pH is a crude measure of the acid-base balance of the body. It may be helpful in determining subtle presence of distal renal tubular disease or pyelonephritis. Urine pH is useful for identifying crystals in urine and determining predisposition to form a given type of stone. See table.
Conditions Associated With Acid Urine |
Metabolic acidosis |
Diabetes mellitus |
Diarrhea |
Starvation |
Respiratory acidosis |
Emphysema |
Sleep |
Renal failure with lack of NH3 buffer |
Gastric suction and vomiting |
Diuretic therapy |
Postprandial alkaline tide (one hour after meal) |
Fanconi syndrome and Milkman syndrome (increased urinary loss of bicarbonate) |
Alkali therapy (citrate, bicarbonate) |
Conditions Associated With Alkaline Urine |
Respiratory alkalosis |
Metabolic alkalosis |
Urea-splitting bacteria (Proteus sp) |
Vegetable diet |
Limitations
This test was developed, and its performance characteristics determined, by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Custom Additional Information
Dietary factors affect urine pH. Alkaline urine is observed in persons who eat large quantities of citrus fruit and vegetables. Acid urine is observed with high meat intake. Pyridium® metabolites may mask the pH reaction. Urine pH >6.5 indicates presence of bicarbonate while pH <5.5 indicates absence of bicarbonate. Consistently acid urine, pH <5.5, is associated with xanthine, cystine, and uric acid stones. Calcium oxalate and apatite stones are not associated with any particular disturbance of urine pH. Alkaline urine pH >7 is associated with calcium carbonate, calcium phosphate, and especially magnesium ammonium phosphate stones. In conjunction with serum pH and bicarbonate levels urine pH may be applied to the study of renal tubular acidification.
Specimen Requirements
Specimen
Urine (random)
Volume
5 mL
Minimum Volume
1 mL
Container
Plastic urine container, no preservative
Collection Instructions
Freshly voided random urine
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
Newborns: 5.0−7.0; thereafter: 4.5−8.0
Storage Instructions
Room temperature
Causes for Rejection
Icteric samples; preservative added
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 013037 | pH, Urine | 2756-5 | 013037 | pH, Urine | 2756-5 | |
| Order Code | 013037 | |||||
| Order Code Name | pH, Urine | |||||
| Order Loinc | 2756-5 | |||||
| Result Code | 013037 | |||||
| Result Code Name | pH, Urine | |||||
| UofM | ||||||
| Result LOINC | 2756-5 |