Test Id : UPH24
pH, 24 Hour, Urine
Useful For
Suggests clinical disorders or settings where the test may be helpful
Assessment of patients with metabolic acidosis, crystalluria, as well as monitoring the effectiveness of alkalinization or acidification of urine for certain medical conditions (eg, treatment of uric acid nephrolithiasis) using a 24-hour collection period
Method Name
A short description of the method used to perform the test
pH Meter
NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test
Aliases
Lists additional common names for a test, as an aid in searching
24 Hour pH
24 HR pH
Specimen Type
Describes the specimen type validated for testing
Urine
Necessary Information
24-Hour volume (in milliliters) is required.
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| TM90 | Collection Duration | |
| VL72 | Volume |
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies:
Diazolidinyl Urea (Germall), 5.0 mL (T822)
Urine Tubes, 10 mL (T068)
Container/Tube: Plastic, 10-mL urine tube or a clean, plastic aliquot container
Specimen Volume: 10 mL
Collection Instructions:
1. Collect urine for 24 hours
2. Add 5 mL of diazolidinyl urea as preservative at start of collection or refrigerate specimen during and after collection.
3. Specimen pH should be between 4.5 and 8 and will stay in this range if kept refrigerated. Specimens with pH >8 indicate bacterial contamination, and testing will be cancelled. Do not attempt to adjust pH as it will adversely affect results.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Special Instructions
Library of PDFs including pertinent information and forms related to the test
Urine Preservative Collection Options
Note: The addition of preservative or application of temperature controls must occur at the beginning of the collection.
| | No |
| Refrigerate | OK |
| Frozen | OK |
| 50% Acetic Acid | No |
| Boric Acid | No |
| Diazolidinyl Urea | Preferred |
| 6M Hydrochloric Acid | No |
| 6M Nitric Acid | No |
| Sodium Carbonate | No |
| Thymol | No |
| Toluene | No |
Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.
1 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Assessment of patients with metabolic acidosis, crystalluria, as well as monitoring the effectiveness of alkalinization or acidification of urine for certain medical conditions (eg, treatment of uric acid nephrolithiasis) using a 24-hour collection period
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
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) have more acid content than others (eg, vegetarian diets).
Changes in urine pH may reflect systemic acid-base disorders. For example, the normal response during metabolic acidosis is a lowering of the urine pH to less than 5. If the pH is greater than 5, then a defect in urine acidification should be considered. A urine pH of greater than 8 is suggestive of infection by a urea-splitting organism such as Proteus mirabilis.
Therapeutic interventions to either alkalinize or acidify the urine are necessary for some diseases. For example, some crystals have a propensity to form in alkaline urine, while others form in relative acidic urine, and changing the pH may reduce stone formation.
Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
4.5-8.0
Interpretation
Provides information to assist in interpretation of the test results
Dependent on clinical condition.
A pH greater than 8 suggests the presence of urinary tract infection with a urea-splitting organism.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
No significant cautionary statements
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Menezes CJ, Worcester EM, Coe FL, Asplin J, Bergsland KJ, Ko B: Mechanisms for falling urine pH with age in stone formers. Am J Physiol Renal Physiol. 2019 Jul 1;317(7):F65-F72
2. Ilyas R, Cho K, Young JG: What is the best method to evaluate urine pH? A trial of three urinary pH measurement methods in a stone clinic. J Endourol. 2015 Jan;29(1):70-74
3. Davidsohn I, Henry JB: Todd-Sanford Clinical Diagnosis by Laboratory Methods. 15th ed. Elsevier; 1974; 43-44
4. Free AH, Free HBS: Urodynamics, concepts relating to urinalysis. Ames Co; 1974:57-61
5. Kaplan LA, Pesce AJ: Clinical Chemistry: Theory, Analysis, Correlation. 3rd ed. Mosby-Year Book Inc; 1996:823
Method Description
Describes how the test is performed and provides a method-specific reference
The pH meter is composed of a glass electrode, calomel electrode and voltmeter. The glass electrode has a fixed acid concentration, yielding a corresponding voltage. The calomel electrode is the reference electrode. Its voltage is independent of the H+ ion concentration. The two electrodes constitute a galvanic cell whose electromotive force is measured by the voltmeter. The meter is calibrated to read in pH units, reflecting the H+ ion concentration. The meter is used to determine pH in 0 to 14 range.(Instruction manual: Fisher Scientific accumet Basic (AB) Benchtop Meters. Fisher Scientific; 68x613601.0 07/2012)
PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information
Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.
Monday through Sunday
Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.
Performing Laboratory Location
Indicates the location of the laboratory that performs the test
Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.
- Authorized users can sign in to Test Prices for detailed fee information.
- Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
- Prospective clients should contact their account representative. For assistance, contact Customer Service.
Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
CPT codes are provided by the performing laboratory.
CPT codes are provided by the performing laboratory.
83986
LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.
| Test Id | Test Order Name | Order LOINC Value |
|---|---|---|
| UPH24 | pH, 24 HR, U | 27378-9 |
| Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
|---|---|---|
| PH24 | pH, 24 HR, U | 27378-9 |
| TM90 | Collection Duration | 13362-9 |
| VL72 | Volume | 3167-4 |