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HelpTest ID 12PTU Protein, Total, 12 Hour, Urine
Useful For
Evaluation of renal disease
Screening for monoclonal gammopathy
Screening for postural (orthostatic) proteinuria
In select clinical situations, collection of a 12-hour specimen may allow more rapid detection of proteinuria states (eg, screening pregnant patients for preeclampsia)
Method Name
Dye Binding (Pyrogallol Red)
Reporting Name
Protein, Total, 12 Hour, USpecimen Type
UrineContainer/Tube: Plastic, 5-mL tube (Supply T465)
Specimen Volume: 5 mL
Collection Instructions:
1. Collect a 12-hour urine specimen.
2. No preservative.
Additional Information: 12-Hour volume is required.
Urine Preservative Collection Options
|
Ambient |
Yes |
|
Refrigerated |
Preferred |
|
Frozen |
Yes |
|
6N HCl |
No |
|
50% Acetic Acid |
No |
|
Na2CO3 |
No |
|
Toluene |
Yes |
|
6N HNO3 |
No |
|
Boric Acid |
Yes |
|
Thymol |
Yes |
Specimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 7 days |
| Frozen | 14 days | |
| Ambient | 7 days |
Clinical Information
Protein in urine normally consists of plasma proteins that have been filtered by glomeruli and not reabsorbed by the proximal tubule, and proteins secreted by renal tubules or other accessory glands. Increased amounts of protein in the urine may be due to:
-Glomerular proteinuria: defects in permselectivity of the glomerular filtration barrier to plasma proteins (eg, glomerulonephritis or nephrotic syndrome)
-Tubular proteinuria: incomplete tubular reabsorption of proteins (eg, interstitial nephritis)
-Overflow proteinuria: increased plasma concentration of proteins that exceeds capacity for proximal tubular reabsorption (eg, multiple myeloma, myoglobinuria)
-Urinary tract inflammation or tumor
-Preeclampsia
-Orthostatic proteinuria
In pregnant women, a urinary protein excretion of >300 mg/24 hours is frequently cited as consistent with preeclampsia, and 12-hour total protein excretion highly correlates with 24-hour values in this patient population.(1,2)
Orthostatic proteinuria is characterized by increased protein excretion in the upright position, but normal levels when supine. This condition can be detected by comparing urine protein levels in a collection split between day and night (see OPTU / Orthostatic Protein, Timed Collection, Urine). Orthostatic proteinuria is common in childhood and adolescence, but rare after age 30.
Reference Values
<115 mg/12 hours (day or night collection)
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
False proteinuria may be due to contamination of urine with menstrual blood, prostatic secretions, or semen.
Protein electrophoresis and immunofixation may be required to characterize and interpret the proteinuria.
Day(s) Performed
Monday through Sunday; Continuously
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. 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