Multiple Myeloma Reporting Tips By Rachel Lei, 5/2/08 We must report numeric values for M-spikes; LabCorp does provide a value on their Serum Protein Electrophoresis (SPEP). However, Quest has not in the past (and may still not). Instead of a numeric value for M-spike, you may see the beneath the gamma value this statement “Serum Protein Electrophoresis Interpretation: Monoclonal protein present in the gamma fraction” or “Serum Protein Electrophoresis Interpretation: a band of restricted mobility in present in the gamma region.” In this case, we must request them to re-read it. If there is a graph showing the electrophoresis gel, an M-spike value can be read by the lab pathologist. Sometimes the abnormal protein consists of free light chains (recall that a full immunoglobulin consists of two heavy chains and two light chains linked together). In this case, the free light chain is so small it will run off the gel way ahead of all other proteins and therefore would fall under the case of “serum M-protein present but too small to quantify”. Usually in the case of light chain disease, a urine protein electrophoresis (UPEP) or a Free-Lite assay will also be done. A UPEP or a Free-Lite that indicates presence of free light chains suggests that the serum M-protein might be present but too small to quantify. When in doubt whether this is the case, call the lab and verify. Forms also sometimes ask for whether serum/urine immunoelectrophoresis was done. Per Dr. Pajon, SPEPs and UPEPs do not give numeric immunoglobulin values, only IEP (immunoelectrophoresis) or immunofixation provide numeric IgG, IgM, and IgA values. Immunofixations are generally indicated clearly on the lab report when they are done. Therefore, if there are numeric serum/urine IgG, IgM, and IgA values, and no indication on the lab that an immunofixation was done, we can report that immunoelectrophoresis was indeed done. On a UPEP or urine immunofixation, if there is no M-spike value listed and a statement is printed such as “Urine protein electrophoresis appears normal with no abnormal bands at a concentration of 80X” or “An apparent normal immunofixation pattern,” the M-protein light chain excretion may be reported as 0.00 mg/24 hr and the Urine M-protein by immunofixation may be reported as negative.