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Test Code QMPTS Monoclonal Protein Isotype, Quantitative, Serum


Ordering Guidance


This test is only orderable as part of a profile. For more information see QMPSS / Monoclonal Protein Study, Quantitative, Serum.



Specimen Required


Only orderable as part of a profile. For more information see QMPSS / Monoclonal Protein Study, Quantitative, Serum.

 

Patient Preparation: None indicated

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Secondary ID

620169

Useful For

Aiding in the diagnosis and monitoring of monoclonal gammopathies if used in conjunction with free light chain studies

 

This test alone is not considered an adequate screen for monoclonal gammopathies.

Testing Algorithm

Only orderable as part of a profile. For more information see QMPSS / Monoclonal Protein Study, Quantitative, Serum.

Method Name

Only orderable as part of a profile. For more information see QMPSS / Monoclonal Protein Study, Quantitative, Serum.

 

Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF)

Specimen Type

Serum

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  7 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Reference Values

Only orderable as part of a profile. For more information see QMPSS / Monoclonal Protein Study, Quantitative, Serum.

 

M-protein Isotype Flag:

Negative

Interpretation:

No monoclonal protein detected.

Interpretation

Immunoaffinity purification followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is performed to identify the immunoglobulin heavy and light chains.

 

The assay examines the mass-to-charge distributions of Ig light chains derived from immunoglobulin G, immunoglobulin A, immunoglobulin M, kappa, and lambda immunopurified from patient serum. Over-expressed Ig (ie, M-proteins or paraproteins) are detected as distinct peaks in the mass-to-charge distributions. Quantitation is accomplished by calculating the percent of monoclonal protein in the charge-to-mass distribution and multiplying this by Ig concentration as measured immunonephelometry.

Method Description

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 serum is applied to 5 separate immunoaffinity resins specific to immunoglobulin G, A, M, K, and L. Unbound protein is washed away and the isolated immunoglobulins are broken down in to their reduced to separate the heavy and light chains subunits to be analyzed via MALDI-TOF MS. The 5 separate spectra from each specimen immunopurification are overlaid and investigated for an overabundance of immunoglobulin and immunoglobulin light chain. Monoclonal protein peaks are integrated based on the modeled polyclonal background. The quantitative value is determined based on the percent area and nephelometric value of the corresponding immunoglobulin.(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

2 to 4 days

Specimen Retention Time

14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

0077U

LOINC Code Information

Test ID Test Order Name Order LOINC Value
QMPTS Quantitative M-protein Isotype, S 74773-3

 

Result ID Test Result Name Result LOINC Value
620875 M-protein GK 74862-4
620876 M-protein GL 74863-2
620877 M-protein AK 74864-0
620878 M-protein AL 74865-7
620879 M-protein MK 74866-5
620880 M-protein ML 74867-3
620881 Glycosylation 104267-0
620874 Flag, M-protein Isotype 94400-9
621012 QMPTS Interpretation 69048-7