Identification of M protein from filter paper using serum protein and immunofixation electrophoresis

Serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) are standard methods for detection and monitoring of monoclonal (M) proteins. However, these tests are rarely available in the remote areas, especially in developing countries. Transportation of fresh serum (FS) samples is also usually inconvenient. This study investigated M-protein identification using serum blot on filter paper (FP). SPE and IFE were performed on FS and FP specimens using the Sebia Hydrasys automated electrophoresis system. Statistical analyses were conducted to assess sample stability and agreement of FS vs FP. The FP method showed good agreement with the FS method. The r values for correlation of albumin levels-α(1), α(2), β, and γ (%)-between FP and FS samples in SPE were all more than 0.95 (P < .01). IFE displayed no significant difference between those 2 methods in the identification of M protein. The FP method demonstrated an accurate and reproducible alternative to FS for identification of M protein using SPE and IFE.