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Identification of a spurious band on serum protein electrophoresis induced by ethanol treatment
1Department of Pathology and Laboratory Medicine, University of Louisville School of Medicine, Louisville, KY 40292, USA.
Background:
Treatment of serum with ethanol at 100 ml/l eliminating fibrinogen from electrophoretic pattern produces an additional band at alpha2/beta junction. This study is to determine the source and the nature of this artifact.
Methods:
The supernatant after ethanol precipitation was used for electrophoresis. Protein concentrations of each fraction in ethanol- and saline-treated samples were compared, and immunofixation electrophoresis (IFE) to identify transferrin, C3, and LDL was performed. C3 IFE was also conducted for fresh sera and sera stored for 2 weeks.
Results:
The artificial band at alpha2/beta junction was identified in ethanol-treated sera but not in saline-treated sera. Protein concentration in the beta fraction was reduced after ethanol treatment as compared to saline-treated samples (n=10, p<0.01). The spurious band at alpha2/beta junction was recognized in C3 IFE. C3 IFE also showed a band at alpha2/beta junction in samples stored for 2 weeks.
Conclusions:
Ethanol treatment of serum creates an artificial band with C3 immunoreactivity at alpha2/beta junction. This could be due to the accelerated hydrolysis of C3 by ethanol treatment. Laboratories using ethanol to evaluate a possible fibrinogen band should be aware of this phenomenon, and the serum protein electrophoretic pattern after ethanol treatment should only be used to rule out fibrinogen.
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