A Comparative Study of Three Fecal Occult Blood Tests in Upper Gastrointestinal Bleeding

Abstract

The purpose of this study was to evaluate the performance characteristics of three fecal occult blood tests (FOBTs): the chemical o-toluidine test, the immunochemical OC-Hemodia test, and the immunochromatographic Quick Chaser Occult Blood (QCOB) test, which detect human hemoglobin and transferrin simultaneously in cases of upper gastrointestinal (GI) bleeding. Included were 48 FOBT specimens in 48 consecutive admission cases of upper GI bleeding (endoscopy confirmed). We excluded those fecal specimens with an obvious tarry and bloody appearance. The QCOB test revealed the highest positive rates of 33/48 (68.8%), and significantly higher positive rates than that of the OC-Hemodia test and o-toluidine test (p < 0.025 and < 0.01, respectively). In the patient group with upper GI bleeding due to gastric and duodenal ulcers, the QCOB test had higher positive rates (68.6%) than did the o-toluidine test (34.3%) (p < 0.01). There was no fecal specimen that was positive for the o-toluidine test or OC-Hemodia test and was negative for the QCOB test. Our results reveal that the QCOB test has significantly higher positive rates of fecal occult blood than either the OC-Hemodia test or o-toluidine test. The QCOB test is better than the other two tests for detecting occult blood in patients with upper GI bleeding.

Cutoff value determines the performance of a semi-quantitative immunochemical faecal occult blood test in a colorectal cancer screening programme

“…Faecal samples, preserved in a plastic container in a liquid buffer, were processed using an OC-Micro instrument (Eiken Chemical Co.) (Levi et al, 2007). As threshold for positivity of the test, the manufacturer recommends a cutoff value of 100 ng ml À1 , which has been applied in several studies (Castiglione et al, 2002;Grazzini et al, 2004;Sohn et al, 2005;Chiang et al, 2006;Fenocchi et al, 2006;Rubeca et al, 2006;Van Rossum et al, 2008). The literature and data provided by the manufacturer show that the test results of the OC-Sensor are reliable in the range from 50 to 2000 ng ml À1 (Vilkin et al, 2005), but in rare cases, the results measured can be much higher.…”

Retrospective investigation of the effectiveness of fecal occult blood test (FOB), PT-APTT in patients admitted to emergency department with gastrointestinal bleeding

“…Chien-Hua Chiang et al worked out three different FOB tests in the patients with upper GIS bleeding, including the chemical o-toluidine test, immunochemical OC-Hemodia test and immunochromatograhic Quick Chaser Occult Blood (QCOB) test, which were found to have accuracy in detecting the upper GIS bleeding as 39.6%, 45.8% and 68.8% respectively [9].…”

False negative fecal occult blood tests due to delayed sample return in colorectal cancer screening

“…As threshold for positivity, the manufacturer recommends a cut-off value of 100 ng/ml, applied in several studies. [7][8][9][10][11][12] The literature as well as data provided by the manufacturer show that the test results of the OC-Sensor 1 are reliable in the range from 50 to 2,000 ng/ml. 2 In a previous publication, we compared the guaiac FOBT Hemoccult 1 with the iFOBT OC-Sensor 1 .…”

“…13 For generalizability, we also present data concerning a cut-off value of 100 ng/ml in the results and the tables, which were applied in several studies. [7][8][9][10][11][12] Colonoscopy and lesions All colonoscopies were performed by experienced gastroenterologists using conscious sedation with midazolam. If the cecum could not be reached during the initial colonoscopy, the procedure was repeated usually under propofol anesthesia.…”