Measurement of β1- and β2-Globulins Improves Detection of M-Spikes on High-Resolution Electrophoresis

High-resolution serum protein electrophoresis (SPE) provides a clearer separation of β1- and β2-globulins than does low-resolution SPE. Currently, immunofixation electrophoresis (IFE) is performed in most laboratories based on high clinical suspicion of a disease associated with a monoclonal gammopathy or an abnormality in the pattern displayed on the electrophoretogram. The aim of this study was to prospectively determine the utility of performing IFE on specimens with increased β1- or β2-globulins on high-resolution SPE but with a normal electrophoretic pattern on visual inspection. SPE was performed with a Sebia-Hydrasys automated electrophoresis system (Hydragel β-1 + β-2 gels; Sebia). The same system was used for IFE with polyclonal anti-human serum for identifying immunoglobulin heavy and light chains. The reference intervals for β1 and β2 concentrations, determined from 100 fresh samples from healthy volunteers in this laboratory, were 4–8 and 1–5 g/L (mean ± 2 SD), respectively. This study received approval from our Institutional Review Board. During the period from March to December 2001, 3179 samples were submitted for SPE. Of these, 963 had IFE performed because of clinical suspicion or abnormalities in the SPE. All serum specimens submitted for SPE with increased β1 or β2 (n = 51) were prospectively evaluated by IFE. Fifteen of the samples had an obvious M-spike that warranted an IFE and were excluded from the analyses. As a control group, 50 samples with protein concentrations within the reference intervals and a visually normal electrophoretogram were also subjected to IFE. Criteria for inclusion were ( a ) no distinct protein band evident outside of the usual six bands (albumin, α1, α2, β1, β2, and γ) and ( b ) an increased β1 or β …