Measurement of total protein for the assessment of orthostatic proteinuria
Only orderable as part of a profile. For more information see:
ORTHP / Orthostatic Proteinuria, Random, Urine
Turbidimetry
Urine
Only orderable as part of a profile. For more information see:
ORTHP / Orthostatic Proteinuria, Random, Urine
Patient Preparation: Specimens should be collected before fluorescein is given or not collected until at least 24 hour later.
Container/Tube: Plastic, 5-mL tube
Specimen Volume: 4 mL
Collection Instructions:
1. This is a nighttime (supine) collection.
2. Void immediately prior to lying down.
3. Collect an 8-hour (nighttime) urine specimen.
4. Upon awaking in the morning, the patient should immediately void into the specimen cup.
4. No preservative.
5. Invert well before taking 4-mL (maximum) aliquot.
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Refrigerated (preferred) | 14 days | |
Frozen | 30 days | ||
Ambient | 24 hours |
Measurement of total protein for the assessment of orthostatic proteinuria
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 evaluates for this condition by demonstrating either significant proteinuria, even while supine, or normal protein excretion. Significant proteinuria, even while supine, suggests that the patient does not have orthostatic proteinuria while normal protein excretion supports the diagnosis. This test is typically done on three consecutive mornings to provide more robust support for the diagnosis.
Not established
First-morning urine protein-to-creatinine ratio of less than 0.20 mg/mg creatinine supports the diagnosis of orthostatic proteinuria, while a result greater than 0.20 mg/mg creatinine does not support this diagnosis.
Further investigation into other etiologies for proteinuria may be warranted.
False proteinuria may be due to contamination of urine with menstrual blood, prostatic secretions, or semen.
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.
Protein electrophoresis and immunofixation may be required to characterize and interpret the proteinuria.
1. Brunzel N: Chemical examination of urine. In: Fundamentals of Urine and Body Fluids. 4th ed. Saunders; 2018:92-94
2. Wilson DM, Anderson RL: Protein-osmolality ratio for the quantitative assessment of proteinuria from a random urinalysis sample. Am J Clin Pathol. 1993 Oct;100(4):419-424
3. Morgenstern BZ, Butani L, Wollan P, Wilson DM, Larson TS: Validity of protein-osmolality versus protein-creatinine ratios in the estimation of quantitative proteinuria from random samples of urine in children. Am J Kidney Dis. 2003 Apr;41(4):760-766
4. Rinehart BK, Terrone DA, Larmon JE, Perry KG Jr, Martin RW, Martin JN Jr: A 12-hour urine collection accurately assesses proteinuria in hospitalized hypertensive gravida. J Perinatol. 1999 Dec;19(8 Pt 1):556-558
5. 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
6. Robinson RR: Isolated proteinuria in asymptomatic patients. Kidney Int. 1980 Sep;18(3):395-406
7. Dube J, Girouard J, Leclerc P, Douville P: Problems with the estimation of urine protein by automated assays. Clin Biochem. 2005 May;38(5):479-485
8. Koumantakis G, Wyndham L: Fluorescein interference with urinary creatinine and protein measurements. Clin Chem. 1991 Oct;37(10 Pt 1):1799
9. 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
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. 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 |
---|---|---|
PRCON | Protein, Total, Random, U | 2888-6 |
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.
|
---|---|---|
PRCON | Protein, Total, Random, U | 2888-6 |