Comparison Of Immunonephelometric And Immunoturbidimetric Methods for Measuring Beta 2-Microglobulin: Fit for Purpose in Routine Clinical Laboratories

Abstract

Serum free beta 2-microglobulin (b2M) level has been regarded as an independent biomarker in several cancers, and has traditionally been analyzed using methods such as Immunonephelometry on specialized analyzers. It is now possible to perform this test on clinical chemistry analyzers, using immunoturbidimetry. The aim of this study was to compare these two methods, for measuring serum b2M level. Fourty three samples which were randomly chosen from sera of patients with various malignant conditions were analyzed for serum b2M level, both by immunonephelometric method in Beckman Immage 800 (Beckman Coulter Inc., CA, USA) nephelometer, and by immunoturbidimetric method in Beckman UniCel DXC 800 Synchron (Beckman Coulter Inc., CA, USA) auto-analyzer. Method comparison demonstrated good agreement between the immunonephelometric and immunoturbidimetric b2M testing, in which we found good correlation (r=0.973) and high accuracy (slope=1.009). As a conclusion, Beckman UniCel DXC 800 Synchron immunoturbidimetric b2M assay is suitable for routine use, and correlates well with representative immunonephelometric assays on the Beckman Immage 800 analyzer. The ability to perform specific protein analyses such as b2M on an integrated clinical chemistry/immunoassay system, can allow consolidation of testing on a single platform and results in improved laboratory operations efficiency. It is thought that immunoturbidimetric method can be used safely in the routine screening of serum b2M level, for different types of malignancies