Test Id : CRT24
Creatinine, 24 Hour, Urine
Useful For
Suggests clinical disorders or settings where the test may be helpful
Urinary creatinine, in conjunction with serum creatinine, is used to calculate the creatinine clearance, a measure of renal function
Normalizing urinary analytes to account for the variation in urinary concentration
Method Name
A short description of the method used to perform the test
Only orderable as part of a profile. For more information see:
-NMH24 / N-Methylhistamine, 24 Hour, Urine
-RB24 / Retinol-Binding Protein, 24 Hour, Urine
-A124 / Alpha-1-Microglobulin, 24 Hour, Urine
Enzymatic Colorimetric Assay
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
Specimen Type
Describes the specimen type validated for testing
Urine
ORDER QUESTIONS AND ANSWERS
| Question ID | Description | Answers |
|---|---|---|
| TM27 | Collection Duration (h) | |
| VL69 | Urine Volume (mL) |
Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing
Only orderable as part of a profile. For more information see:
-NMH24 / N-Methylhistamine, 24 Hour, Urine
-RB24 / Retinol-Binding Protein, 24 Hour, Urine
-A124 / Alpha-1-Microglobulin, 24 Hour, Urine
Urine Preservative Collection Options
Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.
| Ambient | Yes |
| Refrigerate | Preferred |
| Frozen | Yes |
| 50% Acetic Acid | Yes |
| Boric Acid | Yes |
| Diazolidinyl Urea | Yes |
| 6M Hydrochloric Acid | Yes |
| 6M Nitric Acid | Yes |
| Sodium Carbonate | Yes |
| Thymol | No |
| Toluene | No |
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.
1 mL
Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected
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) | 30 days | |
| Ambient | 14 days | ||
| Frozen | 30 days |
Useful For
Suggests clinical disorders or settings where the test may be helpful
Urinary creatinine, in conjunction with serum creatinine, is used to calculate the creatinine clearance, a measure of renal function
Normalizing urinary analytes to account for the variation in urinary concentration
Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Creatinine is formed from the metabolism of creatine and phosphocreatine, both of which are principally found in muscle. Thus, the amount of creatinine produced is in large part dependent upon the individual's muscle mass and tends not to fluctuate much from day-to-day.
Creatinine is not protein-bound and is freely filtered by glomeruli. All of the filtered creatinine is excreted in the urine.
Renal tubular secretion of creatinine also contributes to a small proportion of excreted creatinine. Although most excreted creatinine is derived from an individual's muscle, dietary protein intake, particularly of cooked meat, can contribute to urinary creatinine levels.
The renal clearance of creatinine provides an estimate of glomerular filtration rate.
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.
Only orderable as part of a profile. For more information see:
-NMH24 / N-Methylhistamine, 24 Hour, Urine
-RB24 / Retinol-Binding Protein, 24 Hour, Urine
-A124 / Alpha-1-Microglobulin, 24 Hour, Urine
Normal values mg per 24 hours:
Males: 930-2955 mg/24 hours
Females: 603-1783 mg/24 hours
Reference values have not been established for patients who are less than 18 years of age.
For SI unit Reference Values, see https://www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Interpretation
Provides information to assist in interpretation of the test results
Decreased creatinine clearance indicates decreased glomerular filtration rate. This can be due to conditions such as progressive renal disease, or result from adverse effect on renal hemodynamics that are often reversible including certain drugs or from decreases in effective renal perfusion (eg, volume depletion or heart failure).
Increased creatinine clearance is often referred to as "hyperfiltration" and is most commonly seen during pregnancy or in patients with diabetes mellitus, before diabetic nephropathy has occurred. It also may occur with large dietary protein intake.
Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The reliability of 24-hour urinary creatinine determinations is, as for all timed urine collections, very dependent on accurately collected 24-hour specimens.
Intraindividual variability in creatinine excretion may be due to differences in muscle mass or amount of ingested meat.
Acute changes in glomerular filtration rate, before a steady state has developed, will alter the amount of urinary creatinine excreted.
Rifampicin, levodopa, and calcium dobesilate (eg, Dexium) cause artificially low creatinine results. As tested, according to CLSI recommendation, methyldopa causes artificially low creatinine results.
Dicynone (Etamsylate) at therapeutic concentrations may lead to falsely low results.
N-ethylglycine at therapeutic concentrations and DL-proline at concentrations greater or equal to 1 mmol/L gives falsely high results.
Clinical Reference
Recommendations for in-depth reading of a clinical nature
1. Delaney MP, Lamb EJ: Kidney disease. In: Rifai N, Horvath AR, Wittwer CT, eds: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1256-1323
2. Meeusen J, Rule A, Voskoboev, N, Baumann N, Lieske J: Performance of cystatin C- and creatinine-based estimated glomerular filtration rate equations depends on patient characteristics. Clin Chem. 2015 Oct;61(10):1265-1272. doi: 10.1373/clinchem.2015.243030
3. Newman DJ, Price CP: Renal function and nitrogen metabolites. In: Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry. 3rd ed. WB Saunders Company; 1999:1204-1270
4. Kasiske BL, Keane WF: Laboratory assessment of renal disease: clearance, urinalysis, and renal biopsy. In: Brenner BM, ed. The Kidney. 6th ed. WB Saunders Company; 2000:1129-1170
Method Description
Describes how the test is performed and provides a method-specific reference
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 ver 2. Roche Diagnostics; V 15.0 03/2019)
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.
- 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 account representative. 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.
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 |
|---|---|---|
| CRT24 | Creatinine, 24 HR, U | 65634-8 |
| 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.
|
|---|---|---|
| CR_A | Creatinine, 24 HR, U | 2162-6 |
| CR_24 | Creatinine Concentration, 24 HR, U | 20624-3 |
| TM27 | Collection Duration (h) | 13362-9 |
| VL69 | Urine Volume (mL) | 3167-4 |