FILTER IMMUNOCYTOLOGY - METHODOLOGIC EVALUATION OF A NEW ASSAY FOR THE DIAGNOSIS OF UROTHELIAL CANCER

OBJECTIVE: Several investigators have demonstrated the high sensitivit y of immunocytology in the diagnosis of transitional cell carcinoma (T CC). A new technique, designated ''filter immunocytology'' (FLIC), sim plifies the technique of quantitative immunocytology, considerably dec reases assay time and increases the percentage of assessable specimens . STUDY DESIGN: Voided urine samples were obtained from 89 patients wi thout evidence of TCC and from 91 patients with histologically proven TCC. The cells were transferred onto a polycarbonate membrane. Immunos taining was performed using monoclonal antibody. Due ABC 3, directed a gainst a differentiation antigen on urothelial cells. Specimens contai ning > 35% positive urothelial cells were regarded as abnormal. RESULT S: 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. Sensitiv ity did not correlate with tumor grade. Despite high interobserver and intrapatient variations regarding the amount of antigen-positive cell s, a concordant attribution to either ''normal'' or ''abnormal'' was m ade in > 95% of cases. Intraobserver variation was small and did not i nfluence the test result. CONCLUSION: These results suggest that FLIC assay may be a valuable adjunct to conventional cytology. A careful pr ospective investigation appears to be worthwhile to further define the indications for this technique.