North American timeline for the adoption of clinically-validated HPV assays used in cervical cancer screening. Adoption milestones are shown in the rectangles; publication of professional guidelines is shown close to the time axis. Abbreviations: ALTS, ASCUS-LSIL Triage Study; FDA, Food and Drug Administration; ASC-US, atypical squamous cells of undetermined significance; CTFPHE, Canadian Task Force for Periodic Health Examination; ACS, American Cancer Society; USPSTF, U.S. Preventive Services Task Force; ACOG, American Congress of Obstetricians and Gynecologists; ASCP, American Society for Clinical Pathology; ASCCP, American Society for Colposcopy and Cervical Pathology; SGO, Society of Gynecologic Oncology.