影响尿核基质蛋白诊断膀胱癌的干扰因素

目的：探讨尿核基质蛋白(NMP22)在膀胱癌诊断中的特异性和阳性预测值价值。方法：对196例临床怀疑膀胱癌的患者，在膀胱镜检查前留取新鲜自排尿．每个尿标本均行尿细胞学、尿常规、尿培养和NMP22检测。所有患者均行膀胱镜检查。结果：196例中，病理检查证实膀胱癌41例，其他疾病155例。41例膀胱癌患者中，检测出NMP22 33例(80．5%)，而尿细胞学检测阳性仅为11例(26．8％)。在67例NMP22异常者中，除33例诊断为膀胱癌外，假阳性为34例，故特异性和阳性预测值分别为78．1％和49．3％。假阳性结果主要出现在泌尿系感染或炎症、泌尿系结石、泌尿系异物、肠道代膀胱、其他泌尿生殖系肿瘤和器械操作6种情况．排除这6种干扰因素后，NMP22检测的特异性和阳性预测值分别升高至96．2％和91．7％。结论：排除干扰因素能明显改善NMP22诊断膀胱癌的特异性和阳性预测值，提高其临床应用价值。

Exclusion criteria improve the usefulness of NMP22 for diagnosing bladder transitional cell carcinoma

Objective:To improve the specificity and positive predictive value of NMP22 for diagnosing bladder transitional cell carcinoma.Methods:A total of 196 patients considered at risk of bladder cancer were asked to submit a single voided urine sample. Each urine sample was examined cytology, urinalysis, culture and NMP22 protein assay, etc. All pltients underwent cystoscopy.Results:In the 196 patients, there were 41 bladder transitional cell carcinoma patients(BTCC) who had been diagnosed by histology. NMP22 was detected in 33( 80.5%) cases of 41 BTCC, whereas cytology was identified only in 11( 26.8%) cases. In the 67 patients with incresased NMP22 values, the 33 identified tumors were accompenied by 34 false-positive values, so the specificity was 78.1% and positive predictive value was 49.3%. These false positive results were owing to urinary inflammation or infection, urinary calculi, foreign body in urinary tract, orthotopic bladder replacement, other genitourinary cancer and urinary tract instrumentation, and so on. The specificity and positive predictive values of NMP22 can improved to 96.2% and 91.7% respectively with the exclusion of above 6 factors. Conclusions:Exclusion of the categories of false positive results can improve the specificity and positive predictive value of NMP22,enhance the clinical use of this urinary tumor marker.