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HelpTest Code RB24 Retinol-Binding Protein, 24 Hour, Urine
Necessary Information
24-hour volume (in milliliters) is required.
Specimen Required
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 5 mL
Collection Instructions:
1. Collect urine for 24 hours.
2. No preservative.
3. Mix well before taking 5-mL aliquot.
Additional Information:
See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Useful For
Assessing renal tubular injury or dysfunction
Screening for other tubular abnormalities
Detecting chronic asymptomatic renal tubular dysfunction.(2)
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| RBP1 | Retinol-Binding Protein, 24-Hour, U | No | Yes |
| RBPCN | Retinol-Binding Protein Conc | No | Yes |
| CRT24 | Creatinine, 24 HR, U | Yes, (order CTU) | Yes |
Special Instructions
Method Name
RBP1: Calculation
RBPCN: Immunonephelometry
CRT24: Enzymatic Colorimetric Assay
Reporting Name
Retinol-Binding Protein, 24-Hour, USpecimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 7 days | |
| Frozen | 7 days |
Reference Values
Retinol-Binding Protein:
≥18 years of age: <273 mcg/24 hour
Reference values have not been established for patients who are less than 18 years.
Creatinine:
Males ≥18: 930-2955 mg/24 hours
Females ≥18: 603-1783 mg/24 hours
Reference values have not been established for patients who are less than 18 years.
Interpretation
Retinol-binding protein above the reference values may be indicative of a proximal tubular dysfunction.
Clinical Reference
1. Kirsztajn GM, Nishida SK, Silva MS, et al. Urinary retinol-binding protein as a prognostic marker in glomerulopathies. Nephron. 2002;90(4):424-431
2. Norden AG, Scheinman SJ, Deschodt-Lanckman MM, et al. Tubular proteinuria defined by a study of Dent's (CLCN5 mutation) and other tubular diseases. Kidney Int. 2000;57(1):240-249
3. Lamb EJ, Jones GJD. Kidney function tests. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:470-517
Day(s) Performed
Monday, Wednesday, Friday
Report Available
1 to 4 daysPerforming 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
83883
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RB24 | Retinol-Binding Protein, 24-Hour, U | 96399-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CR_A | Creatinine, 24 HR, U | 2162-6 |
| RBP1 | Retinol-Binding Protein, 24-Hour, U | 18362-4 |
| RBPCN | Retinol-Binding Protein Conc | 96406-4 |
| TM27 | Collection Duration (h) | 13362-9 |
| VL69 | Urine Volume (mL) | 3167-4 |
| CR_24 | Creatinine Concentration, 24 HR, U | 20624-3 |
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.