Test Id : SUPRA
Effective May 14, 2025: This test is temporarily unavailable due to a nationwide reagent issue. The downtime is expected to be >30 days. An alternative test is not available. See test notification here.
Supersaturation Profile, Random, Urine
Useful For
Suggests clinical disorders or settings where the test may be helpful
Diagnosis and management of patients with renal lithiasis:
-Predicting the likely composition of the stone, in patients who have a radiopaque stone, for whom stone analysis is not available which may help in designing a treatment program
-Identifying specific risk factors for stones formation using a random urine collection
-Monitoring the effectiveness of therapy by confirming that the crystallization potential has indeed decreased
-Evaluation of kidney excretion of acid and urine pH
Profile Information
A profile is a group of laboratory tests that are ordered and performed together under a single Mayo Test ID. Profile information lists the test performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| Test Id | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SRINT | Supersaturation, Random, U 1 | No | Yes |
| RANAU | Sodium, Random, U | Yes, (order RNAUR) | Yes |
| RAKUR | Potassium, Random, U | Yes, (order RKUR) | Yes |
| RACAL | Calcium, Random, U | Yes, (order CACR3) | Yes |
| RAMAG | Magnesium, Random, U | Yes, (order MAGRU) | Yes |
| RACLU | Chloride, Random, U | Yes, (order RCHLU) | Yes |
| RAPOU | Phosphorus, Random, U | Yes, (order RPHOC) | Yes |
| RASUL | Sulfate, Random, U | No | Yes |
| RACIT | Citrate Excretion, Random, U | Yes, (order CITRA) | Yes |
| RAOXU | Oxalate, Random, U | Yes, (order ROXUR) | Yes |
| RAPHU | pH, Random, U | No | Yes |
| RAURA | Uric Acid, Random, U | Yes, (order RURC1) | Yes |
| RACTU | Creatinine, Random, U | Yes, (order RCTUR) | Yes |
| RAOSM | Osmolality, Random, U | No | Yes |
| RAAMM | Ammonium, Random, U | Yes, (order RAMBO) | Yes |
Method Name
A short description of the method used to perform the test
RACIT, RAAMM, RAOXU: Enzymatic
RAOSM: Freezing Point Depression
RASUL: High-Performance Ion Chromatography (HPIC)
RAMAG: Colorimetric Endpoint Assay
RACAL, RAPOU: Photometric
RAPHU: pH Meter
RANAU, RAKUR, RACLU: Potentiometric, Indirect Ion-Selective Electrode (ISE)
RACTU: Enzymatic Colorimetric Assay
RAURA: Uricase
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
Brushite Crystal
Calcium Oxalate Crystal
Hydroxyapatite Crystal
Kidney Stone Disease
Kidney Stone Profile
Stone Risk Profile
Uric Acid Crystals
Specimen Type
Describes the specimen type validated for testing
Urine
Ordering Guidance
A timed 24-hour urine collection is the preferred specimen for measuring and interpreting this profile to determine kidney stone risk factors (SUP24 / Supersaturation Profile, 24 Hour, Urine). Random urine collections with individual analytes normalized to urinary creatinine may be of some clinical use in patients who cannot collect a 24-hour specimen, typically small children. Therefore, this test is offered on random collections for children less than 16 years old.
X-ray dyes and contrast media will affect uric acid test results.
-If a kidney X-ray with dye or computerized tomography (CT) scan with contrast has been performed, patient should wait a minimum of 1 day before starting collection.
-If a cholangiography (bile duct X-ray) has performed, patient should wait 7 days before starting collection.
-Urine must be collected before tablets have been taken for gallbladder X-ray, otherwise patient should wait 7 days before starting collection.
Necessary Information
Patient's age is required.
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Supplies:
-Urine Tubes, 10 mL (T068)
-Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: 90 mL urine container
Submission Container/Tube: 2 x 10 mL plastic urine tubes and 5 x 5 mL plastic urine tubes
Specimen Volume: 40 mL
Collection Instructions:
1. Collect a random urine specimen, mix collection container thoroughly and divide the urine into 7 plastic tubes (2 x 10 mL and 5 x 5 mL).
2. Refrigerate specimen after collection. Specimen pH should be between 4.5 and 8 and will stay in this range if kept refrigerated. Specimens with pH above 8 indicate bacterial contamination, and testing will be canceled. Do not attempt to adjust pH as it will adversely affect results.
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
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.
30 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
| pH <4.5 or >8.0 | Reject |
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) | 14 days | |
| Ambient | 72 hours | ||
| Frozen | 14 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Diagnosis and management of patients with renal lithiasis:
-Predicting the likely composition of the stone, in patients who have a radiopaque stone, for whom stone analysis is not available which may help in designing a treatment program
-Identifying specific risk factors for stones formation using a random urine collection
-Monitoring the effectiveness of therapy by confirming that the crystallization potential has indeed decreased
-Evaluation of kidney excretion of acid and urine pH
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Urine is often supersaturated, which favors precipitation of several crystalline phases such as calcium oxalate, calcium phosphate, and uric acid. However, crystals do not always form in supersaturated urine because supersaturation is balanced by crystallization inhibitors that are present in the urine. Urinary inhibitors include ions (eg, citrate) and macromolecules but remain poorly understood.
Urine supersaturation is calculated by measuring the concentration of all the ions that can interact (potassium, calcium, phosphorus, oxalate, uric acid, citrate, magnesium, sodium, chloride, sulfate, and pH). Once the concentrations of all the relevant urinary ions are known, a computer program can calculate the theoretical supersaturation with respect to the important crystalline phases (eg, calcium oxalate).(1)
Since the supersaturation of urine has been shown to correlate with stone type,(2) therapy is often targeted towards decreasing the urinary supersaturations identified. Treatment strategies include alterations in diet and fluid intake as well as drug therapy; all designed to decrease the urine supersaturation.
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.
The following analytes do not have any established reference values:
Sodium, potassium, chloride, phosphorus, citrate, sulfate, and oxalate
pH: 4.5-8.0
CREATININE
> or =18 years old: 16-326 mg/dL
Reference values have not been established for patients who are younger than 18 years.
OSMOLALITY
0-11 months: 50-750 mOsm/kg
> or =12 months: 150-1,150 mOsm/kg
AMMONIUM
18-77 years: 3-65 mmol/L
No reference values established for patients who are younger than 18 years or older than 77 years.
CALCIUM
1 month-<12 months: 0.03-0.81 mg/mg creat
12 months-<24 months: 0.03-0.56 mg/mg creat
24 months-<3 years: 0.02-0.50 mg/mg creat
3 years-<5 years: 0.02-0.41 mg/mg creat
5 years-<7 years: 0.01-0.30 mg/mg creat
7 years-<10 years: 0.01-0.25 mg/mg creat
10 years-<18 years: 0.01-0.24 mg/mg creat
18 years-83 years: 0.05-0.27 mg/mg creat
Reference values have not been established for patients who are younger than 1 month or older than 83 years.
MAGNESIUM
Magnesium/Creatinine Ratio:
1 month-<12 months: 0.10-0.48 mg/mg creat
12 months-<24 months: 0.09-0.37 mg/mg creat
24 months-<3 years: 0.07-0.34 mg/mg creat
3 years-<5 years: 0.07-0.29 mg/mg creat
5 years-<7 years: 0.06-0.21 mg/mg creat
7 years-<10 years: 0.05-0.18 mg/mg creat
10 years-<14 years: 0.05-0.15 mg/mg creat
14 years-<18 years: 0.05-0.13 mg/mg creat
18 years-83 years: 0.04-0.12 mg/mg creat
Reference values have not been established for patients who are younger than 1 month or older than 83 years.
Interpretation
Provides information to assist in interpretation of the test results
Delta G (DG), the Gibbs free energy of transfer from a supersaturated to a saturated solution, is negative for undersaturated solutions and positive for supersaturated solutions. In most cases, the supersaturation levels are slightly positive, even in normal individuals, but are balanced by an inhibitor activity.
While the DG of urine is often positive, even in the urine of non-stone formers, on average, the DG is more positive in those individuals who do form kidney stones. The reference values are derived by comparing urinary DG values for the important stone-forming crystalline phases between a population of stone formers and a population of non-stone formers. Those DG values that are outside the expected range in a population of non-stone formers are marked abnormal.
A normal or increased citrate value suggests that potassium citrate may be a less effective choice for treatment of a patient with calcium oxalate or calcium phosphate stones.
If the urine citrate is low, secondary causes should be excluded including hypokalemia, renal tubular acidosis, gastrointestinal bicarbonate losses (eg, diarrhea or malabsorption), or an exogenous acid load (eg, excessive consumption of meat protein).
An increased urinary oxalate value may prompt a search for genetic abnormalities of oxalate production (ie, primary hyperoxaluria). Secondary hyperoxaluria can result from diverse gastrointestinal disorders that result in malabsorption. Milder hyperoxaluria could result from excess dietary oxalate consumption or reduced calcium (dairy) intake, perhaps even in the absence of gastrointestinal disease.
Low urine ammonium and high urine pH suggest renal tubular acidosis. Such patients are at risk of calcium phosphate stones.
The results can be used to determine the likely effect of a therapeutic intervention on stone-forming risk. For example, taking oral potassium citrate will raise the urinary citrate excretion, which should reduce calcium phosphate supersaturation (by reducing free ionic calcium), but citrate administration also increases urinary pH (because it represents an alkali load), which promotes calcium phosphate crystallization. The net result of this or any therapeutic manipulation could be assessed by collecting a 24-hour urine and comparing the supersaturation calculation for calcium phosphate before and after therapy.
Important stone-specific factors:
-Calcium oxalate stones: Urine volume, calcium, oxalate, citrate, and uric acid excretion are all risk factors that are possible targets for therapeutic intervention.
-Calcium phosphate stones (apatite or brushite): Urinary volume, calcium, pH, and citrate significantly influence the supersaturation of calcium phosphate. Of note, a urine pH below 6 may help reduce the tendency for these stones to form.
-Uric acid stones: Urine pH, volume, and uric acid excretion levels influence the supersaturation. Urine pH is especially critical, in that uric acid is unlikely to crystallize if the pH is above 6.
-Sodium urate stones: Alkaline pH and high uric acid excretion promote stone formation.
A low urine volume is a universal risk factor for all types of kidney stones.
The following reference means for calculated supersaturation apply to 24-hour timed collections. No information is available for random collections.
Supersaturation Reference Means (Delta G: DG)
Men:
Calcium oxalate: 1.89 DG
Brushite: 0.46 DG
Hydroxyapatite: 4.19 DG
Uric acid: 1.18 DG
Women:
Calcium oxalate: 1.59 DG
Brushite: -0.11 DG
Hydroxyapatite: 3.62 DG
Uric acid: 0.89 DG
Values for individual analytes that are part of this panel on a random urine collection are best interpreted as a ratio to the creatinine excretion. Following are pediatric reference ranges for the important analytes for which pediatric data is available.
Oxalate/Creatinine (mg/mg)
| Age (year) | 95th Percentile |
| 0-0.5 | <0.175 |
| 0.5-1 | <0.139 |
| 1-2 | <0.103 |
| 2-3 | <0.08 |
| 3-5 | <0.064 |
| 5-7 | <0.056 |
| 7-17 | <0.048 |
Matos V, Van Melle G, Werner D, Bardy D, Guignard JP. Urinary oxalate and urate to creatinine ratios in a healthy pediatric population. Am J Kidney Dis. 1999;34(2):e1
Uric Acid/Creatinine (mg/mg)
| Age (year) | 5th Percentile | 95th Percentile |
| 0-0.5 | >1.189 | <2.378 |
| 0.5-1 | >1.040 | <2.229 |
| 1-2 | >0.743 | <2.080 |
| 2-3 | >0.698 | <1.932 |
| 3-5 | >0.594 | <1.635 |
| 5-7 | >0.446 | <1.189 |
| 7-10 | >0.386 | <0.832 |
| 10-14 | >0.297 | <0.654 |
| 14-17 | >0.297 | <0.594 |
Matos V, Van Melle G, Werner D, Bardy D, Guignard JP. Urinary oxalate and urate to creatinine ratios in a healthy pediatric population. Am J Kidney Dis. 1999;34(2):e1
Phosphate/Creatinine (mg/mg)
| Age (year) | 5th Percentile | 95th Percentile |
| 0-1 | >0.34 | <5.24 |
| 1-2 | >0.34 | <3.95 |
| 2-3 | >0.34 | <3.13 |
| 3-5 | >0.33 | <2.17 |
| 5-7 | >0.33 | <1.19 |
| 7-10 | >0.32 | <0.97 |
| 10-14 | >0.22 | <0.86 |
| 14-17 | >0.21 | <0.75 |
Matos V, van Melle G, Boulat O, Markert M, Bachmann C, Guignard JP. Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr. 1997;131(2):252-257
Magnesium/Creatinine (mg/g)
| Age (year) | 95th Percentile |
| 0-1 | <0.48 |
| 1-2 | <0.37 |
| 2-3 | <0.34 |
| 3-5 | <0.29 |
| 5-7 | <0.21 |
| 7-10 | <0.18 |
| 10-14 | <0.15 |
| 14-17 | <0.13 |
Matos V, van Melle G, Boulat O, Markert M, Bachmann C, Guignard JP. Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr. 1997;131(2):252-257
Citrate/Creatinine (mg/mg)
| Age (year) | 95th Percentile |
| 5-18 | <1.311 |
Srivastava T, Winston MJ, Auron A, Alon US. Urine calcium/citrate ratio in children with hypercalciuric stones. Pediatr Res. 2009;66(1):85-90
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The urine is often supersaturated with respect to the common crystalline constituents of stones, even in non-stone formers.
Individual interpretation of the supersaturation values in the context of the clinical situation is critical. In particular, treatment may reduce the supersaturation with respect to one crystal type but increase the supersaturation with respect to another. Therefore, the specific goals of treatment must be considered when interpreting the test results.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Werness PG, Brown CM, Smith LH, Finlayson B. EQUIL2: a BASIC computer program for the calculation of urinary saturation. J Urol. 1985;134(6):1242-1244
2. Parks JH, Coward M, Coe FL. Correspondence between stone composition and urine supersaturation in nephrolithiasis. Kidney Int. 1997;51(3):894-900
3. Finlayson B. Calcium stones: Some physical and clinical aspects. In: David DS, ed. Calcium Metabolism in Renal Failure and Nephrolithiasis. John Wiley and Sons; 1977:337-382
4. Burtis CA, Bruns DE. Tietz Fundamentals of Clinical Chemistry and Molecular Diagnostics. 7th ed. Saunders; 2014
5. Tiselius HG, Daudon M, Thomas K, Seitz C. Metabolic work-up of patients with urolithiasis: indications and diagnostic algorithm. Eur Urol Focus. 2017;3(1):62-71. doi:10.1016/j.euf.2017.03.014
Method Description
Describes how the test is performed and provides a method-specific reference
The major analytes evaluated are potassium, calcium, phosphorus, oxalate, uric acid, citrate, magnesium, sodium, chloride, sulfate, and pH. Given the measured urine concentrations of these analytes and the known affinity constants of the ions for each other at the given pH, a computer program (EQUIL2) calculates a supersaturation for each ion pair of interest (eg, calcium oxalate). Results are expressed as a delta G (DG) value for each ion pair. DG is the Gibbs free energy of transfer from a supersaturated to a saturated solution.(Werness PG, Brown CM, Smith LH, Finlayson B. EQUIL2: a BASIC computer program for the calculation of urinary saturation. J Urol. 1985;134[6]:1242-1244; Moreira DM, Friedlander JI, Hartman C, Elsamra SE, Smith AD, Okeke Z. Using 24-hour urinalysis to predict stone type. J Urol. 2013;190[6]:2106-2111)
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.
Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
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.
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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 was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.
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.
82310-Calcium
82436-Chloride
82507-Citrate excretion
82570-Creatinine
83735-Magnesium
83935-Osmolality
83945-Oxalate
83986-pH
84105-Phosphorus
84133-Potassium
84300-Sodium
84392-Sulfate
84560-Uric acid
82140-Ammonium
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 |
|---|---|---|
| SUPRA | Supersaturation, Random, U | 101929-8 |
| 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.
|
|---|---|---|
| OXMCO | Oxalate, Random, U (mmol/L) | 15086-2 |
| OXGCO | Oxalate, Random, U (mg/L) | 2700-3 |
| OXUCR | Oxalate/Creatinine Ratio, Random, U | 13483-3 |
| 31246 | Interpretation | 69051-1 |
| 616399 | Calcium Oxalate Crystal | In Process |
| 616400 | Brushite Crystal | In Process |
| 616401 | Hydroxyapatite Crystal | In Process |
| 616402 | Uric Acid Crystal | In Process |
| RAUAC | Uric Acid, Random, U | 3086-6 |
| UACCR | Uric Acid/Creat Ratio, Random, U | 3089-0 |
| RASUC | Sulfate, Random, U | 2975-1 |
| POUCO | Phosphorus, Random, U | 2778-9 |
| PHOCR | Phosphorus/Creat Ratio, Random, U | 11141-9 |
| RAPHU | pH, Random, U | 2756-5 |
| RAOSU | Osmolality, Random, U | 2695-5 |
| RANAC | Sodium, Random, U | 2955-3 |
| RAMGC | Magnesium, Random, U | 19124-7 |
| MAGCR | Magnesium/Creat Ratio, Random, U | 13474-2 |
| RACTU | Creatinine, Random, U | 2161-8 |
| RAKUC | Potassium, Random, U | 2828-2 |
| RACLC | Chloride, Random, U | 2078-4 |
| CITCO | Citrate Excretion, Random, U | 2128-7 |
| CITCR | Citrate/Creatinine Ratio, Random, U | 13722-4 |
| RACAC | Calcium, Random, U | 17862-4 |
| CALCR | Calcium/Creatinine Ratio, Random, U | 9321-1 |
| RAAMM | Ammonium, Random, U | 1842-4 |