Validation of the Diagnostic Value of NMP22® BladderChek® Test as a Marker for Bladder Cancer by Photodynamic Diagnosis

ObjectivesThe aim of the present study was to validate the sensitivity and specificity of the new “point-of-care” NMP22® BladderChek® test compared to photodynamic diagnosis (PDD).MethodsVoided urine samples from 100 patients with suspicion of bladder cancer were collected to perform the NMP22® BladderChek® test and voided urinary cytology. The nuclear matrix protein 22 (NMP22) levels were measured by a lateral flow immunochromatographic qualitative assay, using 10 U/ml as the cut-off value. Subsequently patients underwent PDD, using 5-aminolevulinic acid or hexyl-aminolevulinate; previous bladder washings for cytology were collected. Sensitivity and specificity of the NMP22® BladderChek® test were compared with cytology and PDD.ResultsForty of the 100 patients had urothelial malignancies (22 pTa, 4 pT1, 3 pT2, 9 carcinoma in situ, 2 pTx; 16 G1, 6 G2, 18 G3). The sensitivity was 65% for the NMP22® BladderChek® test, 44% for voided cytology, 75% for washing cytology, and 93% for PDD. Specificity rates were 40%, 78%, 62%, and 43%, respectively. Positive predictive values were 0.42, 0.58, 0.53, and 0.52 and the negative predictive values 0.63, 0.68, 0.82, and 0.9, respectively.ConclusionsThe results demonstrate that the NMP22® BladderChek® is an easily applied test, giving diagnostic findings within 30 min. However, validated by the highly sensitive PDD, the NMP22® BladderChek® test demonstrates poor specificity and sensitivity and, therefore, cannot be recommended for screening or surveillance in daily clinical routine use. Further studies with careful patient selection are necessary to identify the patient population that might benefit from the NMP22® BladderChek® test.