Ko Cynthia W, Dominitz Jason A, Nguyen Toan D
Department of Medicine, University of Washington, Seattle, Washington, USA.
Am J Med. 2003 Aug 1;115(2):111-4. doi: 10.1016/s0002-9343(03)00294-8.
Guaiac-based fecal occult blood tests are limited by poor patient compliance, and low sensitivity, specificity, and positive predictive value. Newer immunochemical-based tests are designed to improve accuracy and patient compliance. We compared patient compliance and the test characteristics of these two types of tests.
The laboratory outcomes associated with use of different fecal occult blood tests were examined in a Veterans Affairs-based general medicine clinic that was divided into two firms with similar patient and provider characteristics. Tests were ordered for colorectal cancer screening or for symptom evaluation. Patients were given one of the two tests depending on their firm. The completion and positivity rates, time to test completion, completion of diagnostic follow-up, and positive predictive values were compared.
The percentage of returned test cards was similar between the two groups (47% [1369/2964] for guaiac-based tests vs. 48% [1410/2965] for immunochemical-based tests) as was the positivity rate (9.0% [122/1396] and [128/1410] for both groups). In patients with positive tests who underwent further colon evaluation, the proportion with adenomas was similar between groups (59% [38/64] vs. 58% [40/69]). However, 17% (12/69) with a positive immunochemical-based test had an adenoma >1 cm or a colorectal malignancy, versus 30% (19/64) for guaiac-based tests (P = 0.09).
Overall, immunochemical-based and guaiac-based fecal occult blood tests had comparable performance. However, although immunochemical-based testing is reported to be easier for patients than guaiac-based testing, we found that patients were no more likely to return cards for analysis. The similar positive predictive value and additional cost of immunochemical-based tests call into question their utility in general practice.
基于愈创木脂的粪便潜血试验受患者依从性差以及灵敏度、特异性和阳性预测值低的限制。新型免疫化学法检测旨在提高准确性和患者依从性。我们比较了这两种检测方法的患者依从性和检测特征。
在一家退伍军人事务部的普通内科诊所中，对使用不同粪便潜血试验的实验室结果进行了检查，该诊所分为两个科室，患者和医护人员特征相似。检测用于结直肠癌筛查或症状评估。根据患者所在科室，给予其两种检测方法中的一种。比较了完成率和阳性率、检测完成时间、诊断性随访的完成情况以及阳性预测值。
两组的检测卡返回率相似（基于愈创木脂的检测为47%[1369/2964]，基于免疫化学的检测为48%[1410/2965]），阳性率也相似（两组均为9.0%[122/1396]和[128/1410]）。在检测呈阳性并接受进一步结肠评估的患者中，两组腺瘤患者的比例相似（59%[38/64]对58%[40/69]）。然而，基于免疫化学的检测呈阳性的患者中有17%（12/69）患有大于1厘米的腺瘤或结直肠癌，而基于愈创木脂的检测为30%（19/64）（P = 0.09）。
总体而言，基于免疫化学和基于愈创木脂的粪便潜血试验性能相当。然而，尽管据报道基于免疫化学的检测对患者来说比基于愈创木脂的检测更容易，但我们发现患者返还检测卡进行分析的可能性并无差异。基于免疫化学的检测相似的阳性预测值和额外成本使其在一般临床实践中的效用受到质疑。
