Test Catalog

Test Id : SSATR

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. This 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
RRSUP Supersaturation, Random, U No Yes
NAUR Sodium, Random, U Yes, (order RNAUR) Yes
KURR Potassium, Random, U Yes, (order RKUR) Yes
CACR2 Calcium, Random, U Yes, (order CACR3) Yes
MAGR Magnesium, Random, U Yes, (order MAGRU) Yes
CLUR Chloride, Random, U Yes, (order RCHLU) Yes
POUR Phosphorus, Pediatric, Random, U Yes, (order RPHOC) Yes
SULFR Sulfate, Random, U No Yes
CITRR Citrate Excretion, Peds, Random, U Yes, (order CITRA) Yes
OXUR Oxalate, Pediatric, Random, U Yes, (order ROXUR) Yes
UPHR pH, Random, U No Yes
URCUR Uric Acid, Random, U Yes, (order RURC1) Yes
CTURR Creatinine, Random, U Yes, (order RCTUR) Yes
UOSMR Osmolality, Random, U No Yes
RAMCN Ammonium, Random, U Yes, (order RAMBO) Yes

Method Name
A short description of the method used to perform the test

CITRR, RAMCN OXUR: Enzymatic

UOSMR: Freezing Point Depression

SULFR: High-Performance Ion Chromatography (HPIC)

MAGR: Colorimetric Endpoint Assay

CACR2: Photometric

POUR: Molybdic Acid

UPHR: pH Meter

NAUR, KURR, CLUR: Potentiometric, Indirect Ion-Selective Electrode (ISE)

CTURR: Enzymatic Colorimetric Assay

URCUR: Uricase

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

No

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

Supersaturation, Peds, Random, U

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

Sodium Urate Crystal

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 (order SAT24 / Supersaturation Profile, 24 Hour, Urine. Random 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.

Additional Testing Requirements

 

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 5 mL Aliquot Tube (T914)

Container/Tube: 3 Plastic, 10-mL urine tubes and 4 plastic, 5-mL tubes

Specimen Volume: 40 mL

Collection Instructions:

1. Collect a random urine specimen and divide the urine into 6 tubes.

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 over 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

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

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. This 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 also present in 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 those urinary supersaturations that are 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.

pH: 4.5 to 8.0

 

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 patient younger than 18 years and older than 77 years of age

 

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 than1 month of age.

Reference values have not been established for patients who are older than 83 years of age.

 

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 of age.

Reference values have not been established for patients who are older than 83 years of age

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 even more positive in those individuals who do form kidney stones. The reference values are simply 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 suggests 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 for calcium phosphate. Of note, a urine pH of less than 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 greater than 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)

Brushite: 0.21 DG

Hydroxyapatite: 3.96 DG

Uric acid: 1.04 DG

Sodium urate: 1.76 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, et al: Urinary oxalate and urate to creatinine ratios in a healthy pediatric population. Am J Kidney Dis. 1999;34: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, et al: Urinary oxalate and urate to creatinine ratios in a healthy pediatric population. Am J Kidney Dis. 1999;34: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, et al: Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr. 1997;131:252-257

 

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, et al: Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population. J Pediatr. 1997;131:252-257

 

Citrate/Creatinine (mg/mg)

Age (year)

95th Percentile

5-18

<1.311

 

Srivastava T, Winston MJ, Auron A, et al: Urine calcium/citrate ratio in children with hypercalciuric stones. Pediatr Res. 2009;66:85-90

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 light 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 Dec;134(6):1242-1244

2. Parks JH, Coward M, Coe FL: Correspondence between stone composition and urine supersaturation in nephrolithiasis. Kidney Int. 1997 Mar;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 Feb;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;134:1242-1244; Moreira DM, Friedlander JI, Hartman C, et al: Using 24-hour urinalysis to predict stone type. J Urol. 2013;190:2106-2111)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

Supplemental RE

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 Friday

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.

2 to 5 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

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 Regional Manager. 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 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 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.

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
SSATR Supersaturation, Peds, Random, U In Process
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.
SULFR Sulfate, Random, U 2975-1
UOSMR Osmolality, Random, U 2695-5
UPHR pH, Random, U 2756-5
CITR1 Citrate Concentration, Peds, Random, U 2128-7
RATO8 Citrate/Creatinine Ratio 13722-4
RCHLU Chloride, Random, U 2078-4
RCTUR Creatinine, Random, U 2161-8
RKUR Potassium, Random, U 2828-2
RNAUR Sodium, Random, U 2955-3
OXCON Oxalate, Pediatric, Random, U 15086-2
OXCO2 Oxalate Concentration 2700-3
RATO7 Oxalate/Creatinine Ratio 13483-3
POCON Phosphorus, Pediatric, Random, U 2778-9
RATO5 Phosphorus/Creatinine Ratio 11141-9
31241 Calcium Oxalate Crystal In Process
31242 Brushite Crystal In Process
31243 Hydroxyapatite Crystal In Process
31244 Uric Acid Crystal In Process
31245 Sodium Urate Crystal In Process
31246 Interpretation 69051-1
URCO2 Uric Acid, Random, U 3086-6
RATO6 Uric Acid/Creat Ratio, Random, U 3089-0
MGCON Magnesium, Random, U 19124-7
MGCTR Magnesium/Creatinine Ratio 13474-2
CALC4 Calcium, Random, U 17862-4
CACTR Calcium/Creatinine Ratio 9321-1
RAMCN Ammonium, Random, U 1842-4

Test Setup Resources

Setup Files
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Sample Reports
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Normal Reports | Abnormal Reports

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