A method for analyzing a sample to detect cells infected by Human Papilloma Virus (HPV) is provided. The method includes passing a medium containing the sample across a filter. The filter has a pore size that is greater than a dimension of a HPV particle, but smaller than a dimension of a HPV infected cell, such that most of the HPV particles pass through the filter, while leaving the cells on the filter. The material collected on the filter is then examined to determine if HPV infected cells are present in the material.