title: Laboratory audit as part of the quality assessment of a primary HPV-screening program.
abstract: BACKGROUND
  As primary HPV screening programs are rolled out, methods are needed for routine quality assurance of HPV laboratory analyzes.
  
  
  OBJECTIVE
  To explore the use of similar design for audit as currently used in cytology-based screening, to estimate the clinical sensitivity to identify women at risk for CIN 3 or worse (CIN3+).
  
  
  METHODS
  Population-based cohort study conducted within the cervical screening program in Stockholm, Sweden, in 2011-2012. All women with histopathologically confirmed CIN3+ in the following two years were identified by registry analysis. Primary HPV and cytology screening results were collected. For women who had not been HPV tested, biobanked cytology samples were HPV-tested. If the original HPV result had been negative, the sample and subsequent biopsies were analyzed with broad HPV typing (general primer PCR and Luminex).
  
  
  RESULTS
  154 women had a biobanked prediagnostic cytology sample taken up to 2 years before a histopathologically confirmed CIN3+. The high-risk HPV-positivity was 97% (148/154 women), whereas 143/154 (94%) women had had a cytological abnormality. Among the six HPV-negative samples, one sample was HPV 33 positive in repeat testing whereas the other five cases were HPV-negative also on repeat testing, but HPV-positive in the subsequent tumor tissue.
  
  
  CONCLUSIONS
  A sensitivity of the HPV test that is higher than the sensitivity of cytology suggests adequate quality of the testing. Regular audits of clinical sensitivity, similar to those of cytology-based screening, should be used also in HPV-based screening programs, in order to continuously monitor the performance of the analyzes.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Hortlund
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Sweden.
authors.forename: Karin
authors.initials: K
authors.lastname: Sundström
authors.affiliation: Department of Laboratory Medicine, Karolinska University Hospital, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Lamin
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Hjerpe
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Sweden. Electronic address: joakim.dillner@ki.se.
authors.forename: Joakim
authors.initials: J
authors.lastname: Dillner
mesh_terms: D054869:Clinical Audit; D020732:Cytogenetic Analysis; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000592:standards; D027383:Papillomaviridae / Q000302:isolation & purification; D030361:Papillomavirus Infections / Q000175:diagnosis / Q000821:virology*; D012680:Sensitivity and Specificity; D013548:Sweden; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000517:prevention & control* / Q000821:virology; D014626:Vaginal Smears
keywords: Audit; HPV; Primary screening; Sensitivity