Orthostatic Protein, Timed Collection, Urine
Use
The test is useful for the diagnosis of orthostatic proteinuria, which is characterized by increased proteinuria when the individual is upright and resolves when supine. This condition is mostly seen in children, adolescents, or young adults, and accounts for most cases of proteinuria in childhood. It usually does not indicate significant underlying renal pathology and often resolves over time. This test characterizes the condition by obtaining two distinct urine collections within a 24-hour period: one while the person is upright and the other while supine.
Special Instructions
Not provided.
Limitations
Reference values have not been established for patients under 18 years of age. Normal protein concentration in urine may rise to 300 mg/24 hours in healthy individuals after vigorous exercise. Newborns might exhibit higher excretion of protein during the first three days of life. The presence of hemoglobin, menstrual blood, prostatic secretions, or semen can elevate protein concentration falsely. Protein electrophoresis and immunofixation may be needed for further characterization.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 1755-8 - Albumin 24h Ur-mRate
- 49002-9 - Albumin ?Tm Ur-mRate
- 13362-9 - Specimen collect Time Ur
- 19153-6 - Specimen vol ?Tm Ur
- 35663-4 - Prot ?Tm Ur-mCnc
- 50209-6 - Albumin sup ?Tm Ur-mRate
Result Turnaround Time
1-4 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
4 mL
Minimum Volume
1 mL from 16-hour (daytime) urine collection/1 mL from 8-hour (nighttime) urine collection
Container
Plastic, 5-mL tube
Collection Instructions
Collect a 16-hour (daytime) urine specimen and an 8-hour (nighttime) urine specimen. No preservative required. Invert well before taking a 4-mL aliquot.
Causes for Rejection
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 14 days |
| Frozen | 30 days |