Filter immunocytology: methodologic evaluation of a new assay for the diagnosis of urothelial cancer.

Abstract

Several investigators have demonstrated the high sensitivity of immunocytology in the diagnosis of transitional cell carcinoma (TCC). A new technique, designated "filter immunocytology" (FLIC), simplifies the technique of quantitative immunocytology, considerable decreases assay time and increases the percentage of assessable specimens. Voided urine samples were obtained from 89 patients without evidence of TCC and from 91 patients with histologically proven TCC. The cells were transferred onto a polycarbonate membrane. Immunostaining was performed using monoclonal antibody. Due ABC 3, directed against a differentiation antigen on urothelial cells. Specimens containing > 35% positive urothelial cells were regarded as abnormal. Of 153 specimens 180 (85%) were assessable. The investigation of 76 specimens from control patients and 77 from patients with TCC yielded a specificity of 86% and a sensitivity of 75%, respectively. Sensitivity did not correlate with tumor grade. Despite high interobserver and intrapatient variations regarding the amount of antigen-positive cells, a concordant attribution to either "normal" or "abnormal" was made in > 95% of cases. Intraobserver variation was small and did not influence the test result. These results suggest that FLIC assay may be a valuable adjunct to conventional cytology. A careful prospective investigation appears to be worthwhile to further define the indications for this technique.