γ/IgG ratio: role in distinguishing monoclonal spikes from fibrinogen.
| Autor: | Lee MT; Immunology Laboratory, Department of Pathology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21287, USA., Caturegli P, Humphrey RL, Thompson RE, Detrick B |
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| Jazyk: | angličtina |
| Zdroj: | Journal of clinical laboratory analysis [J Clin Lab Anal] 2011; Vol. 25 (5), pp. 332-6. |
| DOI: | 10.1002/jcla.20480 |
| Abstrakt: | 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 region fraction/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. (© 2011 Wiley-Liss, Inc.) |
| Databáze: | MEDLINE |
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