2001 Volume 30 Issue 4 Pages 272-279
Separax-SP membrane (FUJIFILM Co.) used in AES 630 automatic electrophoresis system (Olympus Co.) has high sensitivity for M-protein detection. However, high concentration of fibrinogen and CRP also forms M-protein-like band in beta to gamma area on this membrane, and it confuses us to differentiate from true M-protein bands. Fibrinogen shows usually arch form band on Separax or Separax-S, but not on Separax-SP membrane. Therefore, it is difficult to differentiate fibrinogen or CRP band from true M-protein band by the electrophoretic pattern itself. Reagent for fibrinogen detection in the test sample, based on latex agglutination is now commercially available. But, it may lead to erroneous judgment to eliminate M-protein band from true M-protein band, because high concentration of serum FDP may show false positive results with this test, and also the fibrinogen fraction is occasionally superimposed on M-protein. It was also confined that M-protein-like band due to high concentration of CRP appears at the same mobility as fibrinogen on Separax-SP membrane. In this respect, we attempted to use the reagent added to FDP blood collecting tube, which consists of thrombin, thrombin-like enzyme from viper venom, aprotinin and calcium chloride, to remove fibrinogen from the test sample for ensuring accurate judgment of M-protein. And we successfully designed a method to differentiate M-protein-like band from true M-protein band by effectively combining the use of the fibrinogen detective reagent and this fibrinogen-removing reagent. After we applied this method in routine work, the cases, which was failed to confirm the M-protein was markedly decreased.
