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Test ID SUPRA Supersaturation Profile, Random, 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


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.


Secondary ID

616375

Useful For

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

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

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

Reporting Name

Supersaturation, Random, U

Specimen Type

Urine

Specimen Minimum Volume

30 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Clinical Information

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

The following analytes do not have any established reference values:

Sodium, potassium, chloride, phosphorus, citrate, sulfate, and oxalate

pH: 4.5-8.0

 

CREATININE

≥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

≥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.

Cautions

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.

Day(s) Performed

Monday through Sunday

Report Available

2 to 5 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

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

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

NY State Approved

No