MASS-FIX is a MALDI-TOF mass spectrometry method Mayo Clinic Laboratories now employs to detect monoclonal proteins. In this "Test in Focus" episode of the "Answers From the Lab" podcast, David Murray, M.D., Ph.D., explains this innovative testing approach that's used to screen patients for plasma cell disorders and monitor patients being treated for multiple myeloma. Dr. Murray also describes the significant advantages MASS-FIX offers over traditional testing methods, including gel electrophoresis.

"We're getting closer to a cure for multiple myeloma. But to get there, we need to detect smaller levels of disease at earlier stages," Dr. Murray says. "In addition, monoclonal therapeutics are now used frequently, and it becomes very difficult to look for monoclonal immunoglobulins as a disease marker when patients are being treated with similar monoclonal proteins. Both of those factors have pushed electrophoresis methods to their analytical limits."

Dr. Murray notes that MASS-FIX has the ability to overcome those limitations and provide both heightened sensitivity and specificity. Because of that, Mayo Clinic has transitioned to using this testing approach in all situations where gel electrophoresis used to be employed. Listen to learn more about how MASS-FIX enhances screening for plasma cell disorders — including multiple myeloma, smoldering myeloma, monoclonal gammopathy of undetermined significance (MGUS), and amyloidosis — as well as improves monitoring and guides treatment for people with multiple myeloma.

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Testing (coming March 2021)

Monoclonal Gammopathy Screen, Serum (Mayo ID: DMOGA)

Protein Electrophoresis and Isotype, Serum (Mayo Test ID: PEISO)

Monoclonal Gammopathy Monitoring, Serum (Mayo ID: TMOGA)

M-Protein Isotype, Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry, Serum (Mayo Test ID: MALD)

Useful for:

Monoclonal Gammopathy Screen, Serum (Mayo ID: DMOGA)

  • Screening and diagnosis of monoclonal gammopathies including analysis of free light chains.
  • Assessing the risk of progression from monoclonal gammopathy of undetermined significance to multiple myeloma.Diagnosis of monoclonal gammopathies, when used in conjunction with locally performed serum free light chain studies (performed at client site).

Protein Electrophoresis and Isotype, Serum (Mayo Test ID: PEISO)

  • Diagnosis of monoclonal gammopathies, when used in conjunction with locally performed serum free light chain studies (performed at client site).

Monoclonal Gammopathy Monitoring, Serum (Mayo ID: TMOGA)

  • Monitoring patients with monoclonal gammopathies.
  • This test is not recommended to screen or establish a first-time diagnosis for a monoclonal gammopathy.

M-Protein Isotype, Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry, Serum (Mayo Test ID: MALD)

  • Monitoring patients with monoclonal gammopathies.
  • This test is not recommended to screen or establish a first-time diagnosis for a monoclonal gammopathy.

Specimen Requirements

Monoclonal Gammopathy Screen, Serum (Mayo ID: DMOGA)

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 2 mL

Collection Instructions: Centrifuge and aliquot serum

Protein Electrophoresis and Isotype, Serum (Mayo Test ID: PEISO), Monoclonal Gammopathy Monitoring, Serum (Mayo ID: TMOGA), and M-Protein Isotype, Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry, Serum (Mayo Test ID: MALD)

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum

Performance Information

Monoclonal Gammopathy Screen, Serum (Mayo ID: DMOGA)

  • Analytic time: 2 days 

Protein Electrophoresis and Isotype, Serum (Mayo Test ID: PEISO)

  • Analytic time: 2 days 

Monoclonal Gammopathy Monitoring, Serum (Mayo ID: TMOGA)

  • Analytic Time: Same day/1 day 

M-Protein Isotype, Matrix-Assisted Laser Desorption-Ionization Time-of-Flight Mass Spectrometry, Serum (Mayo Test ID: MALD)

  • Analytic Time: Same day/1 day 

Additional Resources

Relevant Publications

  • Abeykoon, J.P., Murray, D.L., Murray, I., Jevremovic, D., Otteson, G.E., Dispenzieri, A., Arendt, B.K., Dasari, S., Gertz, M., Gonsalves, W.I., Kourelis, T.V., Muchtar, E., Dingli, D., Warsame, R., Go, R.S., Lacy, M.Q., Leung, N., Buadi, F., Lin, Y., Kyle, R.A., Rajkumar, V., Kumar, S. and Kapoor, P. (2021), Implications of detecting serum monoclonal protein by MASS‐fix following stem cell transplantation in multiple myeloma. Br J Haematol. https://doi.org/10.1111/bjh.17195 
  • Dispenzieri, A., Larson, D.R., Rajkumar, S.V. et al. N-glycosylation of monoclonal light chains on routine MASS-FIX testing is a risk factor for MGUS progression. Leukemia 34, 2749–2753 (2020). https://doi.org/10.1038/s41375-020-0940-8 
  • 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;92:772-779.
  • Mills JR, Kohlhagen MC, Dasari S, et al. Comprehensive Assessment of M-proteins Using Nanobody Enrichment Coupled to MALDI-TOF Mass Spectrometry. Clin Chem. 2016;62(10):1334-1344.
  • Mills JR, Kohlhagen MC, Willrich MAV, et al. A Universal Solution for eliminating false positives in myeloma due to therapeutic monoclonal antibody interference. Blood. 2018;132(6):670-672.
  • Kourelis T, Murray DL, Dasari S, et al. MASS-FIX may allow identification of patients at risk for light chain amyloidosis before the onset of symptoms. Am J Hematol. 2018;93(11):368-E370.
  • Mills JR, Barnidge DR, Dispenzieri A, Murray DL. High-sensitivity blood-based M-protein detection in sCR patients with multiple myeloma. Blood Cancer J. 2017;7(590).
Samantha Rossi

Samantha Rossi

Samantha Rossi is a Digital Marketing Manager at Mayo Clinic Laboratories. She supports marketing strategies for product management and specialty testing. Samantha has worked at Mayo Clinic since 2019.