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HelpTest ID OPTU Orthostatic Protein, Timed Collection, Urine
Useful For
Diagnosis of orthostatic proteinuria
As a second-order test for additional characterization of proteinuria <3 grams/24 hours, particularly in children or adolescents
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| DOPTU | Daytime Orthostatic Protein, U | No | Yes |
| NOPTU | Nighttime Orthostatic Protein, U | No | Yes |
Special Instructions
Method Name
Dye Binding (Pyrogallol Red)
Reporting Name
Orthostatic Protein, USpecimen Type
UrineThis collection process requires 2 separate urine collections within a 24-hour period.
Collect specimen per instructions in Orthostatic Protein Measurement 24-Hour Urine Collection Site Instructions (Supply T546) in Special Instructions.
Forms: Orthostatic Protein Measurement 24-Hour Urine Patient Collection Instructions in Special Instructions
Daytime Collection
Container/Tube: Plastic, 5-mL tube (Supply T465)
Specimen Volume: 4 mL
Collection Instructions:
1. Collect a 16-hour (daytime) urine specimen.
2. No preservative.
3. Mix well before taking 4-mL aliquot.
Additional Information: Starting and ending times of daytime collection and 16-hour volume are required.
Nighttime (Supine) Collection
Container/Tube: Plastic, 5-mL tube (Supply T465)
Specimen Volume: 4 mL
Collection Instructions:
1. Collect an 8-hour (nighttime) urine specimen.
2. No preservative.
3. Mix well before taking 4-mL aliquot.
Additional Information: Starting and ending times of nighttime collection and 8-hour volume are required.
Specimen Minimum Volume
1 mL from 16-hour (daytime) urine collection/1 mL from 8-hour (nighttime) urine collection
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 14 days | |
| Ambient | 7 days |
Clinical Information
Orthostatic proteinuria refers to the development of increased proteinuria that develops only when the person is upright and resolves when recumbent or supine. This condition is usually seen in children, adolescents, or young adults, and accounts for the majority of cases of proteinuria in childhood.
Orthostatic proteinuria usually does not indicate significant underlying renal pathology, and is usually not associated with other urine abnormalities such as hypoalbuminemia, hematuria, red blood cell casts, fatty casts, etc. Orthostatic proteinuria typically resolves over time.
This test characterizes this condition by obtaining 2 urine collections within a 24-hour time frame, 1 collection obtained while the person is recumbent or supine, the other when upright.
Reference Values
Nighttime (supine) collection: <57 mg/8 hours
Reference values have not been established for patients <18 years of age.
Reference values have not been established for patients >83 years of age.
Daytime collection: <153 mg/16 hours
Reference values have not been established for patients <18 years of age.
Reference values have not been established for patients >83 years of age.
Cautions
It is not unusual for urine protein excretion derived from supine collections to be somewhat lower than protein excretion derived from upright collections. However, orthostatic or postural proteinuria is characterized by a supine excretion rate of <50 mg/8 hours.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
84156 x 2