Total Protein in Urine with Roche c502

Detection of Total Protein in Urine with Roche c502

Test Name: In vitro test for the quantitative determination of protein in human urine on Roche/Hitachi cobas c systems.
Method Name: The Roche Diagnostics Urinary/CSF Protein assay is based on the method described by Iwata and Nishikaze, later modified by Luxton, Patel, Keir, and Thompson. In this method, benzethonium chloride reacts with protein in a basic medium to produce a turbidity that is more stable and evenly distributed than that observed with the SSA or TCA methodologies.
Results: Technical Range: 4-200 mg/dL
Reportable Range: 4.6-198.8 mg/dL
Reference Ranges: 24-hour period: <120 mg/dL
Clinical Significance: Protein measurements in urine are used in the diagnosis and treatment of disease conditions such as renal or heart diseases, or thyroid disorders, which are characterized by proteinuria or albuminuria.

Cerebrospinal fluid (CSF) protein measurements are used in the diagnosis and treatment of conditions such as meningitis, brain tumors and infections of the central nervous system.

Urine is formed by ultrafiltration of plasma across the glomerular capillary wall. Proteins with a relative molecular mass > 40000 are almost completely retained, while smaller substances easily enter the glomerular filtrate. Most CSF protein originates by diffusion from plasma across the blood CSF barrier.

Elevated levels occur as a result of increased permeability of the blood CSF barrier or with increased local synthesis of immunoglobulins.

Turbidimetric methods using trichloroacetic acid (TCA) or sulfosalicylic acid (SSA) precipitate proteins in the sample depending on their size; the resulting turbidity may be unstable and flocculate. Reagents of dye binding methods such as Coomassie blue and pyrogallol red molybdate react with proteins depending on their amino acid composition but may stain glass and plastic ware. Due to their reaction mechanisms all methods, turbidimetric and colorimetric, exhibit different sensitivities to various proteins, especially to protein fragments such as Bence Jones proteins and small proteins such as α1 microglobulin.

Submission Criteria: For specimen collection and preparation, only use suitable tubes or collection containers.
Only the specimens listed below were tested and found acceptable.
Use 24-hour urine specimens. Use no preservatives. Refrigerate specimen
during collection.

The sample types listed were tested with a selection of sample collection tubes that were commercially available at the time of testing, therefore not all available tubes of all manufacturers were tested. Sample collection systems from various manufacturers may contain differing materials which could affect the test results in some cases.  When processing samples in primary tubes (sample collection systems), follow the instructions of the tube manufacturer.
Storage and Stability:    30 days at -20°C
7 days at 2-8°C
1 day at 20-25 °C

Rejection Criteria: Rejection criteria include but are not limited to:
1. Mismatched requisitions
2. Specimens without patient identifiers
3. Specimens stored or shipped incorrectly
4. Specimens collected using expired tubes/cups
5. Specimens with inappropriate preservatives such as formalin or formaldehyde,
disinfectant, or detergent added
6. Specimens not analyzed within the appropriate time frame
7. Specimens with quantity not sufficient
8. Hematuria
9. Specimens contaminated with fecal matter
10. Specimens submitted without approval
Authorization: Diagnostic testing can only be performed with approval from an authorized provider/agency.
Turn Around Time: 1 day.