免疫法便隐血试验对大肠良恶性疾病的诊断价值研究

Value of immunochemical fecal occult blood tests in diagnosis of intestinal benign and malignant diseases

目的探讨免疫法便隐血试验(IFOBT)在诊断大肠良恶性疾病中的诊断价值,提高大肠癌癌前疾病的早期筛查水平。方法对332例行结肠镜检查者进行免疫法便隐血试验,应用OC-MICRO全自动便隐血分析仪对便隐血结果进行分析,分别计算不同阳性阈值下的敏感性、特异性、阳性预测值(PPV)、阴性预测值(NPV)。应用ELISA法检测外周血CEA、CA19-9水平及其敏感性、特异性、PPV、NPV。结果共纳入研究332例,其中男176例(53.0%),女156例(47.0%),分为结肠镜正常组183例,炎症性肠病(IBD)组34例,大肠息肉组79例(其中腺瘤型息肉25例,高危腺瘤12例)和大肠癌组36例。当便隐血试验阳性阈值为200ng/mL时,各组特异度为94.5%,各组敏感度分别为88.2%(IBD组)、86.1%(大肠癌组)、52.0%(腺瘤型息肉组)、50.0%(高危腺瘤组)和34.2%(大肠息肉组),与阳性阈值为100 ng/mL和150 ng/mL时相比较均无显著差异(P>0.05)。外周血CEA在正常组、IBD组和大肠息肉组之间无显著差异(P>0.05),大肠癌组和正常组之间有显著差异(P=0.006)。外周血CA19-9在正常组、IBD组和大肠癌组之间无显著差异(P>0.05)。CEA、CA19-9及二者联合检测其特异度均为100%,与免疫法便隐血无显著差异(P=1.000),其敏感度在IBD组、大肠息肉组、腺瘤型息肉组、高危腺瘤组和大肠癌组分别为:CEA(0、6.7%、0、8.3%、36.7%)、CA19-9(0、0、0、0、16.7%)、二者联合(0、3.3%、0、8.3%、40.0%)。CEA、CA19-9在诊断大肠癌时敏感度均低于免疫法便隐血(P=0.000),其PPV与免疫法便隐血无显著差异(P>0.05),NPV明显低于免疫法便隐血(P=0.000)。在诊断高危腺瘤时,免疫法便隐血NPV明显高于肿瘤标志物(P=0.000),敏感度、特异度和PPV均与肿瘤标志物无显著差异(P均>0.05)。结论免疫法便隐血在IBD、大肠腺瘤型息肉和大肠癌的诊断方面具有较高的敏感性和特异性,在大肠癌的诊断中比CEA、CA19-9具有更高的敏感度,该方法是较好的大肠良恶性疾病筛查和诊断的指标。

Objective To investigate the value of immunochemical fecal occult blood tests（IFOBT） in diagnosis of intestinal benign and malignant diseases and to raise the screening level of precancerous lession of large intestine.Methods The IFOBT was carried out in 332 patients who were checked-up by colonoscopy.The result of IFOBT was analyzed by OC-MICRO analysator and the sensitivity,specificity,positive predictive value（PPV）,and negative predictive value（NPV） were calculated respectively in different threshold value.The levels of CEA and CA19-9 were detected by ELISA,and the sensitivity,specificity,PPV and NPV were calculated.Results One hundred and seventy-six male（53.0%） and 156 female（47.0%） were enrolled in the 332 cases.And then they were divided into six groups： normal group（183 cases）,IBD group（34 cases）,polyp intestinal group（79 cases）,adenoma polyp group（25 cases）,high-risk adenoma group（12 cases） and colorectal carcinoma group（36 cases）.When the positive threshold value was 200 ng/mL,the specificity was 94.5% and the sensitivity were 88.2%（IBD group）,86.1% （colorectal carcinoma group）,52.0%（adenoma polyp group）,50.0%（high-risk adenoma group） and 34.2%（polyp intestinal group）,which were not significantly different compared with those of positive threshold value at 100 ng/mL and 150 ng/mL（P0.05,respectively）.There was no significant difference in CEA level of peripheral blood among normal group,IBD and polyp intestinal group（P0.05）.There was significant difference in CEA level between the normal group and colorectal carcinoma group（P=0.006）.There was no significant difference in the level of CA19-9 among the normal group,IBD and the cancer of large intestine group（P0.05）.When detecting the CEA,CA19-9 and joint detection,the specificities were all 100%,which were not significantly different compared with that of IFOBT（P=1.000）.The sensitivity of CEA were 0,6.7%,0,8.3% and 36.7% in the IBD group,polyp intestinal,adenoma polyp,high-risk adenoma and colorectal carcinoma groups respectively.The sensitivity of CA19-9 were 0,0,0,0 and 16.7% and the sensitivity of CEA and CA19-9 joint detection was 0,3.3%,0,8.3% and 40.0% in above-mentioned groups,respectively.The sensitivity and NPV of CEA and CA19-9 were lower than IFOBT（P=0.000）,while the PPVs were not markedly different compared with that of IFOBT（P0.05） in diagnosis of colorectal cancer.The NPV of IFOBT was higher than CEA and CA19-9（P=0.000）,but the sensitivity,specificity and PPV had no significant difference compared with CEA and CA19-9（P0.05,respectively） in diagnosis of high-risk adenoma.Conclusion The IFOBT has the higher sensitivity and specificity than CEA and CA19-9 in diagnosis of IBD,adenoma polyp group and cancer of large intestine group,especially the higher sensitivity in colorectal carcinoma.The IFOBT is an important index in screening and diagnosis of intestinal innocent and malignant disease.