MiniTEM™ is a low-voltage transmission electron microscope system designed for nanoparticle characterization. The high-quality images it acquires reveal particle morphologies that can be transformed into accurate metrics. A metric for sample purity based on the ratio of the total area of debris to that of intact Adenovirus particles is presented in this study. The automated analysis that MiniTEM offers encompasses a far larger number of particles compared with studies performed manually using conventional electron microscopy, resulting in accurate and statistically significant results. This combination of visual proof and metric values is not achievable from indirect methods like dynamic light scattering, nor is it feasible with conventional EM due to the very long hours of manual work required. Analysis time on MiniTEM in this study saves about 65 hours compared with conventional TEM operation. With MiniTEM process operators can rapidly and reliably compare samples from different purification steps or product formulations.