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HelpTEST ID MPQU Monoclonal Protein Quantitation, 24 Hour, Urine
Shipping Instructions
Refrigerate specimen during collection and send refrigerated.
Necessary Information
24-Hour volume (in milliliters) is required.
Specimen Required
Supplies: Urine Container, 60 mL (T313)
Submission Container/Tube: Plastic, 60-mL urine bottle
Specimen Volume: 50 mL
Collection Instructions:
1. Collect urine for 24 hours and refrigerate during collection.
2. Aliquot between 30 mL and 50 mL urine into plastic, 60-mL urine bottle.
Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens for multiple collections.
Useful For
Monitoring patients with monoclonal gammopathies using 24-hour urine collections
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| PTU3 | Protein, Total, 24 HR, U | Yes, (Order PTU) | Yes |
| PEU | Protein Electrophoresis, 24 Hr, U | No | Yes |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| MPTU | M-protein Mass-Fix, 24 HR, U | No | No |
Testing Algorithm
Urine protein electrophoresis alone is not considered an adequate screening for monoclonal gammopathies.
If a discrete electrophoresis band is identified, the laboratory will evaluate the urine protein electrophoresis and, if necessary, perform urine M-protein isotyping by MASSFIX at an additional charge.
Special Instructions
Method Name
PTU3: Turbidimetry
PEU: Agarose Gel Electrophoresis
MPTU: Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS)
Reporting Name
M-protein Quantitation, 24 HR, USpecimen Type
UrineSpecimen Minimum Volume
30 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerated (preferred) | 14 days |
| Frozen | 5 days | |
| Ambient | 24 hours |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitabilityClinical Information
Urine proteins can be grouped into 5 fractions by protein electrophoresis:
-Albumin
-Alpha-1
-Alpha-2
-Beta-globulin
-Gamma-globulin
One or more quantifiable monoclonal proteins may be present and reported as M spike
The urine total protein concentration, the electrophoretic pattern, and the presence of a monoclonal immunoglobulin light chain may be characteristic of monoclonal gammopathies such as multiple myeloma, primary systemic amyloidosis, and light chain deposition disease.
The following algorithms are available:
Reference Values
PROTEIN, TOTAL
<229 mg/24 h
Reference values have not been established for patients who are younger than 18 years.
ELECTROPHORESIS, PROTEIN
The following fractions, if present, will be reported as mg/24 h:
Albumin
Alpha-1-globulin
Alpha-2-globulin
Beta-globulin
Gamma-globulin
MASSFIX M-PROTEIN ISOTYPE
M-protein Isotype MS:
No monoclonal protein detected
Flag M-protein Isotype MS:
Negative
Cautions
Patients suspected of having a monoclonal gammopathy may have a normal urine protein electrophoretic pattern, and these patients should have M-protein isotyping performed.
Monoclonal gammopathies are rarely seen in patients younger than 30 years.
Hemolysis may cause a discrete band on protein electrophoresis, which will be negative on M-protein isotyping.
Penicillin may split the albumin band.
Radiographic agents may produce an uninterpretable pattern.
Method Description
Total Protein:
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)
Electrophoresis:
Urine proteins are separated in an electric field according to their size, shape, and electric charge (Helena SPIFE Touch). The separation is performed on agarose gels. The proteins are visualized by staining with acid blue and the intensity of staining is quantitated by densitometry (Helena Quick Scan Touch). Multiplying by the urine protein concentration converts the percentage of protein in each fraction into urine concentration.(Instruction manual: SPIFE Touch. Helena Laboratories, Corp; 11/2016; package insert: SPIFE Touch SPE Pro 277. Helena Laboratories, Corp; 06/2018; Keren DF, Humphrey RL: Clinical indications and applications of serum and urine protein electrophoresis. In: Detrick BD, Hamilton RG, Schmitz JL eds. Manual of Molecular and Clinical Laboratory Immunology. 8th ed. 2016:chap 8)
Mayo Clinic MASSFIX:
The Mayo Clinic MASSFIX M-protein isotype by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is performed with immunoaffinity purification followed by MALDI-TOF MS analysis. For the immunoaffinity purification, patient sample is applied to 5 separate immunoaffinity resins (CaptureSelect, Life Sciences) specific to immunoglobulin G, A, M, K, and L. Unbound protein is washed away and the isolated immunoglobulins are reduced to separate the heavy and light chains subunits to be analyzed via MALDI-TOF MS. The 5 separate spectra from each patient immunopurification are overlaid and investigated for an overabundance of immunoglobulin and immunoglobulin light chain.(Milani P, Murray DL, Barnidge DR, et al. The utility of MASS-FIX to detect and monitor monoclonal proteins in the clinic. Am J Hematol. 2017;92[8]:772-779. doi:10.1002/ajh.24772)
Day(s) Performed
Monday through Friday
Report Available
4 to 6 daysSpecimen Retention Time
See Individual Test IDsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
84156
84166
0077U (if appropriate)
Forms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.