Do liquid-based preparations of urinary cytology perform differently than classically prepared cases? Observations from the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytology.

Abstract

Abstract Context.—The cytomorphology of liquid-based preparations in urine cytology is different than classic slide preparations. Objectives.—To compare the performance of liquid-based preparation specimens to classically prepared urine specimens with a malignant diagnosis in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytology. Design.—Participant responses between 2000 and 2007 for urine specimens with a reference diagnosis of high-grade urothelial carcinoma/carcinoma in situ/dysplasia (HGUCA), squamous cell carcinoma, or adenocarcinoma were evaluated. ThinPrep and SurePath challenges were compared with classic preparations (smears, cytospins) for discordant responses. Results.—There were 18 288 pathologist, 11 957 cytotechnologist, and 8086 “laboratory” responses available. Classic preparations comprised 90% (n = 34 551) of urine challenges; 9% (n = 3295) were ThinPrep and 1% (n = 485) were SurePath. Concordance to the general category of “positive-malignan...