Ancillary studies in cytology: Secondary or necessary?

Ancillary studies are rapidly becoming an integral and necessary aspect of cytologic analysis. In addition to morphologic features, cytologic specimens contain an enormous amount of information content within their molecules that should be tapped to add value to these samples. Fortunately, a large number of existing and emerging technologies exist to provide access to this information. Adoption of these technologies will require continued attention to fundamental aspects of specimen procurement, handling, and processing to ensure testing accuracy. Successful implementation of ancillary studies will depend on rigorous validation of assays and the development of evidence-based guidelines for their use in patients. Cytopathologists must embrace the role of ancillary test stewardship to ensure the future clinical use of cytologic specimens.