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Test ID: SULFU Sulfate, 24 Hour, Urine

Reporting Name

Sulfate, 24 Hr, U

Useful For

Assessing the nutrition intake of animal protein


The calculation of urinary supersaturation of various crystals or stones

Clinical Information

Urinary sulfate is a reflection of dietary protein intake, particularly meat, fish, and poultry, which are rich in sulfur-containing amino acids methionine and cysteine. Urinary sulfate can be used to assess dietary protein intake for nutritional purposes. A protein-rich diet has been associated with an increased risk for stone formation, possibly due, in part, to an increase in urinary calcium excretion caused by acid production from metabolism of sulfur-containing amino acids.(1,2) Indeed, urinary sulfate excretion is higher in patients who have kidney stones than in individuals who do not form stones. Thus, urinary sulfate excretion may provide an index for protein-induced calciuria.(1)


Sulfate is a major anion in the urine that has significant affinity for cations and modulates the availability of cations for reacting with other anions in the urine. It thus is an important factor of urinary supersaturation(3) for various crystals or stones such as calcium oxalate, hydroxyapatite, and brushite. For example, a high sulfate concentration may modulate the availability of calcium for reacting with oxalate and thus affect the propensity for calcium oxalate stone or crystal formation. Urinary sulfate also has a major impact on buffering or providing hydrogen ions and as such modulates the supersaturation of uric acid.


Urinary sulfate is a reflection of dietary protein intake, particularly of meat, and thus can be used as an index of nutritional protein intake.


It also is used in the calculation of urinary supersaturation of various crystals or stones.

Report Available

1 to 3 days

Day(s) Performed

Monday through Friday

Clinical Reference

1. Rodgers A, Gauvin D, Edeh S, et al. Sulfate but not thiosulfate reduces calculated and measured urinary ionized calcium and supersaturation: implications for the treatment of calcium renal stones. PLoS ONE. 2014;9(7):e103602. doi:10.1371/journal.pone.0103602

2. Magee EA, Curno R, Edmond LM, Cummings JH. Contribution of dietary protein and inorganic sulfur to urinary sulfate: toward a biomarker of inorganic sulfur intake. Am J Clin Nutr. 2004;80(1):137-142

3. Houterman S, van Faassen A, Ocke MC, et al. Is urinary sulfate a biomarker for the intake of animal protein and meat?. Cancer Lett. 1997;114(1-2):295-296

Method Name

High-Pressure Ion Chromatography (HPIC)

Specimen Type


Necessary Information

24-Hour volume is required.

Specimen Required

Supplies: Sarstedt 5 mL Aliquot Tube (T914)

Container/Tube: Plastic, 5-mL urine tube

Specimen Volume: 4 mL

Collection Instructions:

1. Collect urine for 24 hours.

2. Collection instructions with no preservative:

-Specimen must be kept refrigerated during and after collection.

3. Collection instructions with preservative:

 a. If preservative is not added before collection, the specimen must be kept refrigerated until preservative is added.

 b. Preservative must be added within 4 hours of the end of collection.

4. 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.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Refrigerated (preferred) 14 days
  Frozen  14 days

Reference Values

7-47 mmol/24 hours

Test Classification

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


LOINC Code Information

Test ID Test Order Name Order LOINC Value
SULFU Sulfate, 24 Hr, U 26889-6


Result ID Test Result Name Result LOINC Value
SLF_U Sulfate, 24 Hr, U 26889-6
TM89 Collection Duration 13362-9
VL71 Urine Volume 3167-4
SUL_C Sulfate Concentration, 24 Hr, U 12920-5

Urine Preservative Collection Options

Note: If the specimen has been refrigerated during the entirety of the collection, the addition of preservative must occur within 4 hours of completion of the collection.







50% Acetic Acid


Boric Acid


Diazolidinyl Urea


6M Hydrochloric Acid


6M Nitric Acid


Sodium Carbonate







If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.

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