Convenient and effective method for removing fibrinogen from serum specimens before protein electrophoresis.
BACKGROUND
Fibrinogen in serum specimens can be misinterpreted on protein electrophoresis as a monoclonal protein. We evaluated selective precipitation of fibrinogen with ethanol.


METHODS
Pooled human plasma was mixed with absolute ethanol or saline (final concentrations of 40, 80, 100, 120, and 160 mL/L) and incubated at 4 degrees C overnight or placed in an ice bath for 15 min. After centrifugation, the supernatants and resuspended pellets were used for protein electrophoresis and quantitative measurements of protein and fibrinogen.


RESULTS
The fibrinogen band was effectively eliminated from the electrophoretic pattern in the plasma samples treated with ethanol at 100 mL/L and incubated in an ice bath for 15 min without a significant change in immunoglobulin concentrations. The 100 mL/L ethanol did not noticeably change the electrophoretic pattern of monoclonal immunoglobulins. This approach allowed analysis of a sample collected from an arteriovenous shunt kept open with heparin.


CONCLUSIONS
Ethanol, 100 mL/L, can selectively precipitate fibrinogen without significantly interfering with the immunoglobulins. The precipitation process can be completed in 15 min at 0-4 degrees C and can avoid the need to obtain another blood sample.
Qiu
Ling L
LL
Department of Pathology and Laboratory Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA.
Levinson
Stanley S
SS
Keeling
Kristen L
KL
Elin
Ronald J
RJ
D000328:Adult; D001798:Blood Proteins / Q000032:analysis*; D001800:Blood Specimen Collection; D011232:Chemical Precipitation; D004586:Electrophoresis; D000431:Ethanol; D005260:Female; D005340:Fibrinogen / Q000302:isolation & purification*; D006403:Hematologic Tests / Q000379:methods*; D006801:Humans; D007136:Immunoglobulins / Q000097:blood; D012997:Solvents
D001798:Blood Proteins; D007136:Immunoglobulins; D012997:Solvents; D000431:Ethanol; D005340:Fibrinogen