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HelpTest ID: OPTU Orthostatic Protein, Timed Collection, Urine
Reporting Name
Orthostatic Protein, UUseful For
Diagnosis of orthostatic proteinuria
As a second-order test for additional characterization of proteinuria of less than 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 |
Specimen Type
UrineOrdering Guidance
This 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 (T546) in Special Instructions.
Necessary Information
This collection process requires 2 separate urine collections within a 24-hour period.
-Submit start and end times for collection and 16-hour volume (required).
-Submit start and end times for collection and 8-hour volume (required).
Specimen Required
Specimens should be collected before fluorescein is given or not collected until at least 24 hour later.
Supplies: 2 Sarstedt 5 mL Aliquot Tube (T914)
Daytime Collection
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 4 mL
Collection Instructions:
1. Collect a 16-hour (daytime) urine specimen.
2. No preservative.
3. Invert well before taking 4-mL aliquot.
4. Do not over fill aliquot tube 4 mL at most.
5. Collect specimen per instructions in Orthostatic Protein Measurement 24-Hour Urine: Collection Site Instructions (T546) in Special Instructions.
Nighttime (Supine) Collection
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 4 mL
Collection Instructions:
1. Collect an 8-hour (nighttime) urine specimen.
2. No preservative.
3. Invert well before taking 4-mL aliquot at most.
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 | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 30 days | ||
| Ambient | 24 hours |
Special Instructions
Reference Values
Nighttime (supine) collection: <68 mg/8 hours
Reference values have not been established for patients <18 years of age.
Daytime collection: <197 mg/16 hours
Reference values have not been established for patients <18 years of age
Test Classification
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.CPT Code Information
84156 x 2
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| OPTU | Orthostatic Protein, U | 1755-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| DPTU | Total Protein, 16 HR, U | 49002-9 |
| NPTU | Total Protein, 8 HR, U | 50209-6 |
| DUR7 | Nighttime collection duration | 13362-9 |
| DUR4 | Daytime collection duration | 13362-9 |
| DVOL | Day volume | 19153-6 |
| VL | Night volume | 19153-6 |
| NPRO | Total Protein Conc, 8 HR, U | 35663-4 |
| DPRO | Total Protein Conc, 16 HR, U | 35663-4 |
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, one collection obtained while the person is recumbent or supine, the other when upright.
Interpretation
A supine 8-hour urine protein excretion of less than 68 mg/8 hours together with either 1) an elevated upright (16-hour) excretion of greater than 197 mg/16 hours, or 2) a 24-hour urine protein excretion of greater than 228 mg/24 hours is considered consistent with orthostatic proteinuria.
Clinical Reference
1. Rinehart BK, Terrone DA, Larmon JE, et al: A 12-hour urine collection accurately assesses proteinuria in hospitalized hypertensive gravida. J Perinatol. 1999;19:556-558
2. Adelberg AM, Miller J, Doerzbacher M, Lambers DS: Correlation of quantitative protein measurements in 8-, 12-, and 24-hour urine samples for diagnosis of preeclampsia. Am J Obstet Gynecol. 2001 Oct;185(4):804-807
3. Rytand DA, Spreiter S: Prognosis in postural (orthostatic) proteinuria: forty to fifty-year follow-up of six patients after diagnosis by Thomas Addis. N Engl J Med. 1981;305(11):618-621
4. Robinson RR: Isolated proteinuria in asymptomatic patients. Kidney Int. 1980;18:395-406
5. Dube J, Girouard J, Leclerc P et al: Problems with the estimation of urine protein by automated assays. Clin Biochem. 2005:38(5) 479-485
6. Koumantakis G, Wyndham, L: Fluorescein interference with urinary creatinine and protein measurements. Clin Chem. 1991;37(10):1799
7. Lamb EJ, Jones GRD: Kidney function tests. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:479-517
Method Name
Turbidimetry
Forms
1. Orthostatic Protein Measurement 24-Hour Urine: Patient Collection Instructions in Special Instructions
2. If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Day(s) Performed
Monday through Sunday
Report Available
Same day/1 to 4 days| mcl-gdnephrotic |