Impact of risk factors on the performance of the nuclear matrix protein 22 point-of-care test for bladder cancer detection

OBJECTIVES To evaluate the impact of different risk factors and symptoms on the performance characteristics of the nuclear matrix protein 22 (NMP22) BladderChek (R) test (Matritech Inc., Newton, MA, USA) for the detection of bladder cancer, as this is a point-of-care assay that measures NMPs in voided urine. PATIENTS AND METHODS In all, 23 academic, private practice and veterans' facilities in 10 states prospectively enrolled consecutive patients from September 2001 to May 2002. Participants included 1328 patients at elevated risk of bladder cancer from factors such as a history of smoking or symptoms including haematuria and/or dysuria. Patients at risk of malignancy of the urinary tract provided a voided urine sample for analysis of NMP22 protein and cytology before cystoscopy. RESULTS Of the 1328 patients: no urinary disease, benign disease and malignancy were found in 545 (41%), 704 (53%) and 79 (6%) patients, respectively. Overall, the positive predictive value (PPV) for detection of bladder cancer was 20.3% (45/222) and negative predictive value (NPV) was 96.9% (1072/1106). The PPV was higher in men (24.0%) than women (13.2%). In men, the PPV increased with smoking (35.4%), gross haematuria (51.2%) and a combination of both factors (70.6%). The impact on the PPV of smoking (9.7%) and gross haematuria (28.6%) was less dramatic in women. The PPV increased from 16.8% in patients aged < 65 years to 23.5% in those aged > 65 years. The NPV remained almost always > 95% except in men with gross haematuria where it decreased to 77% in smokers and 94% in non-smokers. CONCLUSION The PPV of the BladderChek test improves in patients at higher risk of bladder cancer reaching 77% in men presenting with gross haematuria who are aged > 65 years and smoke. The NPV is highest in women aged < 65 years, up to 100%.