COMPARISON OF URINE COLLECTION METHODS FOR EVALUATING URINARY NUCLEARMATRIX PROTEIN, NMP22, AS A TUMOR-MARKER

Purpose: The nuclear matrix protein, NMP22, has been shown to be a use ful tumor marker for identifying patients with a high likelihood of ra pid recurrence of transitional cell carcinoma of the urinary tract aft er surgical treatment. Currently measurement of NMP22 involves 3 urine voids collected during a 24-hour period, which are pooled and assayed as a single sample. This study was performed to determine whether any single void would yield similar results to the pooled 3-void sample. Materials and Methods: A total of 2,018 urine samples (3 voids per sam ple) was included in the study. All analyses were performed using the nonparametric Wilcoxon signed rank test for matched pairs. Results: An alysis showed that the NMP22 level of a single void collected between midnight and noon was similar to the NMP22 level of the pooled 3-void sample. Receiver operating characteristics curves of the midnight-to-n oon single void and the pooled 3-void sample were similar for predicti ng recurrence postoperatively in patients with urinary tract transitio nal cell carcinoma. Conclusions: One void collected between midnight a nd noon compares favorably with the current 3-void collection method f or determining NMP22 levels in urine.