Sensitivity of urinary quantitative immunocytology with monoclonal antibody 486 P3/12 in 241 unselected patients with bladder carcinoma. We investigated the sensitivity of quantitative immunocytology with our monoclonal antibody 486 P3/12 in 241 unselected patients with transitional cell carcinoma. Immunocytology yielded a sensitivity of 91.8%, 89.4% and 92.9% for grade 1, 2 and 3 tumors, respectively. Standard cytology was positive in 59.2%, 63.8% and 84.7%, respectively. Deoxyribonucleic acid flow cytometry, used in the first 69 patients, was positive in only 27.7%, 48.6% and 57.1%, respectively. 