Pak Cheung Chan, Angeline Yasodhara and Dorothy Truong
Objective: Serum protein electrophoresis (SPE) is commonly used to detect and quantify monoclonal immunoglobulins/components (MC). SPE resolves serum proteins into 5 or 6 major fractions, including albumin. A split or double albumin band in SPE is called bisalbuminemia or alloalbuminemia, a condition caused by genetic or acquired changes. Although isolated cases of bisalbuminemia have been reported in patients with monoclonal gammopathy (MG), there has been no study linking the two statistically or pathophysiologically. The objective of this study is, thus, to determine if bisalbuminemia is significantly associated with MG, and hence to provide value justification for its reporting in SPE.
Methods: We conducted a retrospective study reviewing over 55,800 consecutive serum protein electrophoretograms for bisalbuminemia between June 2005 and October 2013. After exclusion of repeats, 33,512 electrophoretograms were available for analysis. MG was confirmed by immunofixation electrophoresis (IFE) and its positivity rate determined in a smaller cohort with 3974 paired IFE and SPE results. SPE and IFE were performed on the Sebia CapillarysTM2 and Sebia PhoresisTM Electrophoresis Systems respectively.
Results: 9 persistent cases with clear double albumin spikes over time (pattern A) and 10 transient cases with a partial albumin split (pattern B) were identified. The prevalence of pattern A, pattern B and pattern A+B were 0.027%, 0.030% and 0.057% (19/33512), respectively. IFE positivity rate was 32.1% (1276/3874). The odds ratios (95% confidence interval) for pattern A, pattern B and patterns A+B bisalbuminemia over MG were 0.604 (0.125-2.91), 0.101 (0.006-1.72) and 0.249 (0.057-1.08) respectively. Chi-square test for independence (association) was not significant in all 3 scenarios (p>0.05).
Conclusion: Bisalbuminemia, genetic or acquired, is a rare incidental SPE finding that is not associated with MG. The extremely low prevalence and a general lack of association with diseases confer little or no clinical utility, nor value for its reporting in SPE.