Diagnosis of recent primary rubella virus infections: Significance of glycoprotein-based IgM serology, IgG avidity and immunoblot analysis

► Diagnosing recent RV infection requires careful serological study and interpretation. ► Comparison of RV glycoprotein vs. whole-virus lysate as substrate for IgM detection. ► Use of glycoprotein instead of lysate improves specificity of indirect IgM ELISA. ► Parallel analysis of avidity and E2-reactivity optimizes serological interpretation.