A Prospective Comparison of the NMP22 Bladderchek® Assay and Voided Urine Cytology in the Detection of Bladder Transitional Cell Carcinoma: Is it Time up for Urine Cytology?

Objectives: To prospectively compare the performance of voided urine cytology (VUC) and the Matritech NMP22 BladderChek® assay (NMP22) in their ability to detect urothelial transitional cell carcinoma (TCC). Methods: Successive patients presenting to our haematuria clinic were enrolled. All patients underwent ultrasound scan (US), intravenous urography (IVU), flexible cystoscopy and VUC. If bladder TCC was detected, urine was tested using the NMP22 BladderChek® assay. The study group (group I) comprised 110 patients diagnosed with bladder tumour on flexible cystoscopy. The control group (group II) included 52 patients with a history of haematuria but no demonstrable bladder tumour. The TCC detecting ability of both the NMP22 BladderChek® assay and VUC were compared. Results: In group I, the NMP22 result was positive in 62.7% (69/110) patients, while a positive VUC result was noted in 52.0% (52/100) patients. The overall sensitivity, specificity, positive predictive and negative predictive values for NMP22 vs. VUC were 62.7% vs. 52.0%; 86.5% vs. 95.5%; 90.8% vs. 96.3% and 52.3% vs. 48.0% respectively (not significant). The performance of both urine tests improved with increasing tumour grade ( p ≤ 0.05). False positive rate in group II was 13.5% (7/52) for NMP22 and 4.5% (2/42) for VUC. Conclusion: The diagnostic accuracy of the NMP22 BladderChek® assay for TCC detection is equivalent to conventional VUC, but the NMP22 BladderChek® has distinct advantages to promote its use over VUC.