Abstract
Serum protein electrophoresis (SPEP) is a standard screening method for detecting monoclonal gammopathies. Presence of fibrinogen, however, can mimic a true monoclonal spike and interfere with accurate monoclonal protein identification. We describe a novel approach for distinguishing fibrinogen spikes from true monoclonal spikes. We classified 600 individual patient samples into four groups: group 1, 58 samples with a fibrinogen spike; group 2, 127 samples with a spike due to a monoclonal gammopathy; group 3, 181 samples with previously established monoclonal gammopathies but resolved posttreatment; and group 4, 234 control samples without monoclonal gammopathies. The value of using a γ regionfraction/IgG ratio in distinguishing fibrinogen from true monoclonal spikes was assessed. The γ/IgG ratio in the fibrinogen group is significantly (P<0.0001) higher than this ratio in the other three groups. A γ/IgG ratio cut-off value of 1.13 discriminates true monoclonal gammopathies from fibrinogen. Moreover, exclusion of elevated IgA or IgM cases improves the ratio's predictive power. The probability cut-off is 0.756, corresponding to a γ/IgG ratio of 1 (93% sensitivity, 91% specificity). Using the γ/IgG ratio improves the screening power of SPEP and offers a simple and reliable diagnostic tool for distinguishing fibrinogen spikes from true monoclonal spikes.
Original language | English (US) |
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Pages (from-to) | 332-336 |
Number of pages | 5 |
Journal | Journal of Clinical Laboratory Analysis |
Volume | 25 |
Issue number | 5 |
DOIs | |
State | Published - 2011 |
Keywords
- Fibrinogen
- Monoclonal gammopathy
- Serum protein electrophoresis (SPEP)
ASJC Scopus subject areas
- Immunology and Allergy
- Hematology
- Public Health, Environmental and Occupational Health
- Clinical Biochemistry
- Medical Laboratory Technology
- Biochemistry, medical
- Microbiology (medical)