Influence of blood cells in urine samples on results of screening for urothelial carcinoma with NMP22 bladder chek

: We compared the sensitivity of Bladder Chek NMP22 with that of urine cytology in bladder cancer patients. Further, we evaluated the usefulness of Bladder Chek NMP22 in patients with benign diseases such as cystitis, urolithiasis, and benign prostate hyperplasia (BPH) and examined how blood cells in urine samples affect the results of Bladder Chek NMP22. Patients with macroscopic hematuria were excluded from this study. Of 77 bladder cancer patients, Bladder Chek NMP22 showed positive in 46.8%, while urine cytology in 33.8% (p = 0.16). Bladder Chek NMP22 and urine cytology showed positive in 31.8 and 0.0% in G1 (p = 0.004), 51.2 and 46.3% in G2 (p = 0.66) and 57.1 and 50% in G3 (p = 0.71); 44.4 and 88.9% in Tis (p = 0.052), 25.6 and 15.4% in Ta (p = 0.27), 72.2 and 33.3% in T1 (p = 0.02) and 81.8 and 54.5% in T2 or higher (p = 0.18), respectively. In bladder cancer patients with microscopic hematuria or pyuria, the positive rates of Bladder Chek NMP22 were 82.1 and 73.1%, respectively, whereas they were 26.5% (p < 0.001) and 33.3% (p = 0.002), respectively, in those without hematuria or pyuria. In 36 cystitis, 20 urolithiasis, and 19 BPH patients, the positive rates of Bladder Chek NMP22 were 58.3, 25.0 and 5.5%, respectively. Bladder Chek NMP22 showed higher sensitivity for detection of bladder cancer, especially in low-grade and low-stage cancers than urine cytology, but the result was likely affected by blood cells in urine samples. Thus, although Bladder Chek NMP22 may be less useful as the first device for screening of urothelial cancer in patients with hematuria or pyuria, it may show results of high quality when used in patients with negative urine cytology after excluding benign diseases.