Immunocytology in the assessment of patients with asymptomatic microhaematuria

Discrimination between malignant and nonmalignant conditions remains the key problem in assessing microhaematuria. This prospective study investigated the role of immunocytology in the evaluation of patients with microhaematuria.

uCyt+ is a commercially available immunocytologic assay based on microscopic detection of tumour-associated antigens on the membrane of urothelial cells by immunofluorescence. Between October 2000 and August 2005, 189 consecutive patients with newly diagnosed painless microhaematuria without prior transitional cell carcinoma were included. All urine samples were examined cytologically and immunocytologically. Of the 189 samples, 178 (94%) were assessable.

Clinical assessment by physical examination, laboratory tests, endoscopy, and imaging modalities found bladder cancer in 8 patients (4%). Further diagnoses were benign prostatic hyperplasia (54 cases, 29%), cystitis (including interstitial cystitis; 20 cases, 11%), urolithiasis (18 cases, 9%), tumours of other origin (6 cases, 2%), and "further conditions" (26 cases, 13%). In 57 patients (30%) the reasons for haematuria were not disclosed. Immunocytology was positive in 7 of 8 bladder tumours (87%) and negative in 154 of 170 patients with haematuria for other reasons (91%).

The high sensitivity and good specificity of immunocytology in the diagnosis of bladder cancer was confirmed in this population with a low disease prevalence. Only one tumour of low malignant potential was missed by immunocytology. If assessment of these patients would have been based only on immunocytology, 154 costly and invasive diagnostic procedures could have been avoided, with only 16 of 170 individuals (9%) undergoing these examinations unnecessarily. The findings justify a prospective investigation of this issue.