Interference Rendering Capillary Electrophoresis of Serum Proteins Uninterpretable

The authors report a clinical case where biological interference rendered the electrophoretic trace of serum proteins obtained by capillary electrophoresis as uninterpretable.

Electrophoresis of serum proteins and immunotyping immunoassay were performed on Capillary 2 Flex Piercing® Sebia.

A 72-year-old male patient was hospitalized in the clinical hematology department for deep lymphadenopathies with hepatocellular failure. The biological assessment revealed chronic renal failure stage G3b, icteric cholestasis with alkaline phosphatase levels, and hepatic cytolysis. Electrophoresis of serum proteins showed a thickening at the base of albumin peak on its anodic slope but, in particular, it revealed the appearance of a super-numerary split peak between albumin and α1 globulins. These peaks made it impossible to identify and integrate peaks. Based on the clinical information, immunotyping immunoassay was performed on the same sample. The comparison of the different curves with the reference curve does not show any monoclonal immunoglobulinopathy but eliminates all the supernumerary peaks. Suspecting an interference, a Hydrasys 2 Scan® agarose gel electrophoresis (Sebia) was run on the same sample; however, it did not show qualitative anomalies interfering with identification and integration of all the peaks.

Our clinical case emphasizes the importance of the knowledge of certain endogenous interferences that may be the origin of unusual images when interpreting electrophoretic profiles, especially in capillary electrophoresis.