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HelpOrder 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 |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 7 days |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.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.
Method Description
Retinol-Binding Protein:
In an immunochemical reaction, urinary retinol-binding protein forms immune complexes with anti-retinol-binding protein-specific antibodies coated onto polystyrene latex particles. The resulting latex bead-antigen-antibody complexes have enhanced light-scattering ability, which is detected with a nephelometer when a beam of light is passed through the sample. The intensity of the scattered light is proportional to the concentration of retinol-binding protein in the sample. The result is evaluated by comparison with a standard of known retinol-binding protein concentration.(Package insert: Human Urine Retinol Binding Protein Nephelometric Kit for use on the Siemens BNII. The Binding Site Group Ltd; V 27, 11/2012)
Creatinine:
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 16.0 02/2022)
Day(s) Performed
Monday, Wednesday, Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83883
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.