Our results also suggest that, when presumptive tests are performed, serological tests must be conducted in up to 7 days, and genotyping must be done in up to thirty days after the application of reagents. Finally, benzidine had the most critical effect on blood sample DNA, inducing degradation only hours after treatment, and this result is consistent with Hochmeister et al. [9], data who found that benzidine in acetic acid decreases the DNA by RFLP analysis. Consequently, benzidine should not be used when subsequent DNA analysis is needed.