Evaluation of kidney disease using a 24-hour urine collection
Screening for monoclonal gammopathy
Turbidimetry
Total Protein
Urine
24-Hour volume (in milliliters) is required.
Question ID | Description | Answers |
---|---|---|
TM23 | Collection Duration | |
VL21 | Urine Volume |
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube: 24-hour graduated urine container with no metal cap or glued insert
Submission Container/Tube: Plastic, 5 mL tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 4 mL
Collection Instructions:
1. Collect urine for 24 hours. Specimens should be collected before fluorescein is given or not collected until at least 24 hour later.
2. No preservative.
3. Invert well before taking 4-mL aliquot.
4. Do not over fill aliquot tube 4 mL at most.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.
Ambient | No |
Refrigerate | Preferred |
Frozen | OK |
50% Acetic Acid | No |
Boric Acid | OK |
Diazolidinyl Urea | OK |
6M Hydrochloric Acid | No |
6M Nitric Acid | No |
Sodium Carbonate | No |
Thymol | OK |
Toluene | No |
1 mL
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 30 days | ||
Ambient | 24 hours |
Evaluation of kidney disease using a 24-hour urine collection
Screening for monoclonal gammopathy
Protein in urine is normally composed of a combination of plasma-derived proteins that have been filtered by glomeruli and have not been reabsorbed by the proximal tubules and proteins secreted by renal tubules or other accessory glands.
Increased amounts of protein in the urine may be due to:
-Glomerular proteinuria: caused by defects in permselectivity of the glomerular filtration barrier to plasma proteins (eg, glomerulonephritis or nephrotic syndrome)
-Tubular proteinuria: caused by incomplete tubular reabsorption of proteins (eg, interstitial nephritis)
-Overflow proteinuria: caused by increased plasma concentration of proteins (eg, multiple myeloma, myoglobinuria)
-Urinary tract inflammation or tumor
> or =18 years: <229 mg/24 hours
Reference values have not been established for patients <18 years of age.
Reference value applies to 24-hour collection.
Total protein greater than 500 mg/24 hours should be evaluated by immunofixation to determine if a monoclonal immunoglobulin light chain is present, and if so, identify it as either kappa or lambda type.
Urinary protein levels may rise to 300 mg/24 hours in healthy individuals after vigorous exercise.
Low-grade proteinuria may be seen in inflammatory or neoplastic processes involving the urinary tract.
False proteinuria may be due to contamination of urine with menstrual blood, prostatic secretions, or semen.
After vigorous exercise, the urinary protein concentration may rise to 300 mg/24 hours in healthy individuals.
Normal newborn infants may have higher excretion of protein in urine during the first 3 days of life. The presence of hemoglobin elevates protein concentration.
1. Delaney MP, Lamb EJ: Kidney disease. In: Rifai N, Horvath AR, Wittwer CT, eds. Textbook of Clinical Chemistry, 6th ed. Elsevier; 2018:1256-1323
2. 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
3. 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
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
The sample is preincubated in an alkaline solution containing EDTA, which denatures the protein and eliminates interference from magnesium ions. Benzethonium chloride is then added, producing turbidity.(Package insert: Total Protein Urine/CSF Gen.3. Roche Diagnostics; V13.0 11/2018)
Monday through Sunday
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.
84156
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
PTU | Protein, Total, 24 HR, U | 2889-4 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
TP2 | Total Protein, 24 HR, U | 2889-4 |
TM23 | Collection Duration | 13362-9 |
VL21 | Urine Volume | 19153-6 |
CONC1 | Total Protein Concentration | 21482-5 |