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 (Cap Laboratory Improvement Programs) (Report)
Urine cytology specimens are commonly encountered in daily practice and include voided/catheterized urines and washings from the bladder, ureters, and renal pelvis. Cytologic examination of urine specimens is often the initial step for bladder cancer screening and diagnosis. However, there is a wide range in the sensitivity and specificity in the diagnosis of low-grade versus high-grade urothelial carcinomas, partially due to the bland nuclear features exhibited by the low-grade lesions. (1-9) The sensitivity of urine cytology for detecting low-grade lesions varies between 26% and 45%, with a specificity of 98%. (5,6) In contrast, cytologic samples from high-grade urothelial carcinoma/carcinoma in situ/dysplasia (HGUCA) exhibit a sensitivity of 70% to 80% with a specificity that approaches 100%. (1-9) Instrumentation for preparation of liquid-based preparations (LBPs) in the cytology laboratory has been available for use with nongynecologic specimens since 1991. Because of potential to improve slide quality and the ensuing familiarity with LBPs from gynecologic cytology, many laboratories are switching to this technology for a variety of nongynecologic specimens including respiratory specimens, body cavity fluids, and urines. The College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytopathology provides an educational program with urine cytology cases using glass slide material. As a result of this shift in the processing paradigm of nongynecologic samples, this program contains both classical slide material and LBPs.