Due to the host cell specificity of CPEs, researchers can also use them to test any discrepancies in an experiment. For many viral infections, different host cell strains may have a characteristic response. Currently, there are many concerns within the research community about the validity and purity of cell strains. Contamination has risen within and among laboratories. CPEs can be used to test the purity of a certain cell line. For example, HeLa CCL-2 is a common cell line used in a wide variety of research areas. To test the purity of the HeLa cells, CPEs were observed that occurred after inoculation with Coxsackievirus B3. These CPEs included morphology changes and cell morbidity rates. Carson et al. determined that the discrepancy is due to the heterogeneous nature of the commercial HeLa cells as compared to the homogeneous nature of HeLa cells that have been propagated for generations in a lab.