A study of cellular counting to determine minimum thresholds for adequacy for liquid-based cervical cytology using a survey and counting protocol.

摘要: BACKGROUND: Liquid-based cytology (LBC) for cervical screening would benefit from laboratory practice guidelines that define specimen adequacy reporting of slides. The evidence base required to cell should incorporate both ThinPrep? (TP; Hologic, Inc., Bedford, MA, USA) and SurePath? (SP; BD Diagnostics, Burlington, NC, USA), the two LBC systems used in UK programmes. OBJECTIVES: objectives this study were determine (1) current England, Wales Scotland, (2) a reproducible method counting, (3) cellularity slides classified as inadequate, negative or abnormal (4) impact varying on likelihood detecting cytological abnormalities. DESIGN: involved four separate arms pursue each objectives. A questionnaire survey laboratories was conducted. standard counting protocol developed by three experienced cytopathologists reliable method. Slide sets which included range abnormalities sent correlation between counts reported outcomes. Dilution samples fluid only (unmixed) dilution with sample containing normal cells (mixed) performed reducing either total count relative proportion cells. SETTING: conducted within programmes using routinely obtained samples, 56 participating NHS laboratories. PARTICIPANTS: samples. INTERVENTIONS: There no clinical intervention. MAIN OUTCOME MEASURES: main outcome measures reliability method, grades levels detection progressively diluted RESULTS: Laboratory varied terms threshold cellular morphological markers adequacy. While SP generally minimum acceptable (MACC) 15,000, MACC employed TP 5000 15,000. showed achieved moderate strong inter-rater reproducibility. Analysis slide revealed large inadequate had above 15,000 SP, 10,000 TP. Inter-rater unanimity greater among more preparations. studies demonstrated than 25 dyskaryotic CONCLUSIONS: Variation demonstrates requirement evidence-based standards designating MACC. This has indicated TP, respectively, achieves balance maintaining sensitivity low inadequacy rates. FUTURE WORK: findings inform development guidelines. FUNDING: National Institute Health Research Technology Assessment programme.