The capacities of differentiation of Mycobacterium bovis BCG from other members of M. tuberculosis complex species using PCR-RFLP, multiplex PCR, and PCR-based genomic deletion analysis approaches were compared. In the study, mycobacteria isolated from patients suspected of adverse events following vaccination with BCG, primarily classified according presence of RD1 marker as virulent and avirulent mycobacteria, were used. The PCR-based genomic deletion analysis was found the best option for mycobacteria diagnostics improvement, as it was capable precisely differentiate virulent and avirulent mycobacteria or virulent species of M. tuberculosis complex. The routine confirmation of mycobacteria species in the cases of adverse events following BCG vaccination is highly expected, especially in clinical practice of patients with primary immunodeficiency.