Obscuring inflammation may occur in association with atrophic vaginitis or infection. A repeat Pap after treatment of atrophy or infection to resolve inflammation is acceptable.
Excess cervical mucus, discharge, and inflammatory exudate from the cervical canal inherently lack adequate squamous cellularity. These interfering substances should be gently removed with a dry gauze or swab during specimen collection; avoid cleaning with saline as the wash may result in acellular to scantly cellular specimen. The other cause of scant cellularity is a blind Pap, often performed in virginal patients.
Besides specimen testing and diagnosis, the laboratory plays a critical role in patient care by providing feedback to the clinicians to facilitate and maintain a desired level of specimen quality. As evidenced above, the majority of unsatisfactory Paps can be avoided by educating providers on patient preparation and specimen collection. Provider education related to the lubricant issue may be most challenging across multiple practice settings. Laboratory and clinical practice managers may have success working with the hospital procurement team to stock the correct choice of lubricants on the clinic shelves. At the University of Connecticut, Hologic and the practice managers worked together to provide in-services for the major clinics, and the outcomes were successful. Compulsory hierarchical review of unsatisfactory Paps is not recommended. However, if applied as an element of the laboratory’s quality assurance, it may help identify deviations early on and an opportunity to educate newly arrived pathologists. Follow-up and maintenance of these processes result in improved laboratory performance and provider satisfaction and less inconvenience to patients, and help to avoid unnecessary health care costs.
Management guidelines.
Current management guidelines for inadequate Pap tests in the setting of cytology, cotesting, or primary HPV screening are detailed in the 2019 ASCCP Risk-Based Management Consensus Guidelines for Abnormal Cervical Cancer Screening Tests and Cancer Precursors (Table 3). Repeating Paps even when an HPV test is negative is still recommended, as there is the potential for false-negative HPV results in the setting of insufficient cellularity. This raises concern in some when it comes to primary HPV screening, given that repeat testing may not be recommended for up to five years after a negative HPV screen. In addition, while most HPV tests employ a genomic internal control, these controls are not specific for epithelial cells, and a “valid” test could represent the presence of other cellular elements with nucleic acids, such as inflammatory cells, endometrium, and even blood. It should also be noted there are circumstances in which lack of an endocervical/transformation zone can impact management, such as for a patient 30 years or older who has adequate negative cytology but not EC/TZ and no HPV or HPV unknown. HPV testing is recommended if possible in this scenario.
Thrall MJ, McCarthy E, Mito JK, Rao J; Clinical Practice Committee of the American Society of Cytopathology. Triage options for positive high-risk HPV results from HPV-based cervical cancer screening: a review of the potential alternatives to Papanicolaou test cytology. J Am Soc Cytopathol. 2025;14(1):11–22.
Nayar R, Wilbur DC, eds. The Bethesda System for Reporting Cervical Cytology: Definitions, Criteria, and Explanatory Notes. 3rd ed. Springer; 2015.
Perkins RB, Guido RS, Castle PE, et al.; 2019 ASCCP Risk-Based Management Consensus Guidelines Committee. 2019 ASCCP risk-based management consensus guidelines for abnormal cervical cancer screening tests and cancer precursors. J Low Genit Tract Dis. 2020;24(2):102–131. Erratum in: J Low Genit Tract Dis. 2020;24(4):427.
Rosa M, Pragasam P, Saremian J, Aoalin A, Graf W, Mohammadi A. The unsatisfactory ThinPrep Pap Test: analysis of technical aspects, most common causes, and recommendations for improvement. Diagn Cytopathol. 2013;41(7):588–594.
Goyal A, Booth CN, Souers RJ, et al. Navigating practice issues related to the unsatisfactory cervicovaginal Papanicolaou test: survey results of laboratories participating in the 2020 College of American Pathologists PAP Education Program. Arch Pathol Lab Med. 2024;148(1):48–54.
Dr. O’Conor is assistant professor, Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville. Dr. Hegde is professor and director of cytopathology, Department of Pathology and Laboratory Medicine, University of Connecticut, Farmington. Dr. Reynolds is professor and director of cytology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Jacksonville, Fla. All are members of the CAP Cytopathology Committee.