Test Catalog

Test Id : RURC1

Uric Acid/Creatinine Ratio, Random, Urine

Useful For
Suggests clinical disorders or settings where the test may be helpful

Differentiation of acute uric acid nephropathy from other causes of acute kidney failure

 

For patients who cannot collect a 24-hour specimen, typically small children, a uric acid to creatinine ratio can be used to approximate 24-hour excretion

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
RTIO1 Uric Acid/Creat Ratio, Random, U No Yes
URCO3 Uric Acid, Random, U No Yes
CRETR Creatinine, Random, U No Yes

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

URCO3: Uricase

CRETR: Enzymatic Colorimetric Assay

RTIO1: Calculation

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

Yes

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

Uric Acid/Creat Ratio, Random, U

Aliases
Lists additional common names for a test, as an aid in searching

Uric Acid, Random, U

Specimen Type
Describes the specimen type validated for testing

Urine

Ordering Guidance

X-ray dyes and contrast media will affect 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.

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Supplies: Aliquot Tube, 5 mL (T465)

Collection Container/Tube: Plastic urine container

Submission Container/Tube: Plastic, 5-mL tube or a clean, plastic aliquot container with no metal cap or glued insert

Specimen Volume: 4 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

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

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) 14 days
Frozen 30 days
Ambient 7 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Differentiation of acute uric acid nephropathy from other causes of acute kidney failure

 

For patients who cannot collect a 24-hour specimen, typically small children, a uric acid to creatinine ratio can be used to approximate 24-hour excretion

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Uric acid is the end-product of purine metabolism. It is freely filtered by the glomeruli and most is reabsorbed by the tubules. There is also active tubular secretion.

 

Increased levels of uric acid in the urine usually accompany increased plasma uric acid levels unless there is a decreased excretion of uric acid by the kidneys. Urine uric acid levels reflect the amount of dietary purines and endogenous nucleic acid breakdown.

 

Acute uric acid nephropathy can cause acute renal failure due to uric acid precipitation within tubules. This is most commonly seen in patients with hematologic malignancies (eg, lymphoma, leukemia), often after acute lysis of cells by chemotherapy. Less commonly this may be seen with seizures, treatment of solid tumors, overproduction of uric acid in metabolic disorders such as Lesch-Nyhan syndrome or decreased uric acid reabsorption in the proximal nephron due to tubular disorder (Fanconi syndrome).

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.

> or =18 years: <0.60 mg/mg creatinine.

Reference values have not been established for patients who are less than 18 years of age.

Interpretation
Provides information to assist in interpretation of the test results

Uric acid excretion can be either decreased or increased in response to a variety of pharmacologic agents.

 

Urine uric acid levels are elevated in states of uric acid overproduction such as in leukemia and polycythemia and after intake of food rich in nucleoproteins.

 

A uric acid to creatinine ratio (mg/mg) greater than 1.0 is consistent with acute uric acid nephropathy, whereas values less than 0.75 are consistent with other causes of acute renal failure.(1)

 

A timed 24-hour collection is usually the preferred method for measuring and interpreting this urinary analyte. Random collections normalized to urinary creatinine may be of clinical use in 2 scenarios, however:

-When acute renal failure secondary to uric acid is suspected, a uric acid to creatinine ratio (mg/mg) greater than 1.0 is consistent with acute uric acid nephropathy, whereas values less than 0.75 are consistent with other causes of acute renal failure.(1)

-In patients who cannot collect a 24-hour specimen, typically small children, a uric acid creatinine ratio can be used to approximate 24-hour excretion. 

 

Pediatric Reference Ranges of Uric Acid/Creatinine (mg/mg)(2)

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

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

High levels of bilirubin and ascorbic acid may interfere with measurement.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Lamb EJ, Jones GRD: Kidney function tests. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:500-503

2. Kelton J, Kelley WN, Holmes EW: A rapid method for the diagnosis of acute uric acid nephropathy. Arch Intern Med. 1978;138(4):612-615

3. 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; Aug;34(2):e1

4. Newman DJ, Price CP: Renal function and nitrogen metabolites. In: Tietz NW, ed. Textbook of Clinical Chemistry. WB Saunders Company, 1999:1245-1250

Method Description
Describes how the test is performed and provides a method-specific reference

Uric acid is oxidized by the specific enzyme uricase to form allantoin and peroxide. Peroxide reacts in the presence of peroxidase and a color reagent to form a red color, the intensity of which is proportional to the uric acid concentration.(Package insert: Roche Uric Acid Plus. Roche Diagnostics; V13.0 05/2019)

 

Creatinine Method: The enzymatic method is based on the determination of sarcosine from creatinine with the aid of creatininase, creatinase, and sarcosine oxidase. The liberated hydrogen peroxide is measured via a modified Trinder reaction using a colorimetric indicator. Optimization of the buffer system and the colorimetric indicator enables the creatinine concentration to be quantified both precisely and specifically.(Package insert: Creatinine plus v2. Roche Diagnostics; V15.0, 03/2019)

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

No

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.

Same day/1 day

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 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.

84560

82570

LOINC® Information

Test Id Test Order Name Order LOINC Value
RURC1 Uric Acid/Creat Ratio, Random, U 3089-0
Result Id Test Result Name Result LOINC Value
Result LOINC Value Tooltip

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports