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

Specimen Required

Patient Preparation: Fasting 12 hours preferred but not required

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container /Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot into a plastic vial.


If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:


 Renal Diagnostics Test Request (T830)

-Hematopathology/Cytogenetics Test Request (T726)

Useful For

Aiding in the diagnosis of monoclonal gammopathies, when used in conjunction with free light chain studies


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

Profile Information

Test ID Reporting Name Available Separately Always Performed
MALDO M-Protein Isotype Only, S No Yes
TMAB Therapeutic Antibody Administered? No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
IFXED Immunofixation Delta and Epsilon, S Yes No

Testing Algorithm

This test includes M-protein isotyping. If a light chain is identified without a corresponding heavy chain during initial testing, immunofixation with IgD and IgE antisera will be performed at an additional charge.

Method Name

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

Reporting Name

M-Protein Isotype Only, S

Specimen Type


Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

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

Reference Values

Negative: No monoclonal protein detected.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information


86334 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MALD M-Protein Isotype Only, S 90990-3


Result ID Test Result Name Result LOINC Value
606982 Flag, M-protein Isotype 94400-9
TMAB Therapeutic Antibody Administered? 98855-0
606590 M-Protein Isotype MALDI-TOF MS 90990-3

Day(s) Performed

Monday through Friday

Report Available

2 to 5 days