Search

Objective: To compare the Hemoccult II and HemoQuant tests regarding their specificity and sensitivity in screening for colorectal neoplasia.Design: Cross-sectional study in which subjects underwent the two tests in parallel, after excluding dietary hemes and peroxidase-rich foods. HemoQuant results were analyzed for three different upper limits of normality (1.5, 2.0, 3.0 mg/g feces).Setting: A university hospital and the surrounding community.Participants: A total of 150 healthy volunteers, 124 patients with colorectal cancer, and 86 patients with adenoma.Main Outcome Measures: Blinded comparison of the specificity and the sensitivity of the two tests for colorectal cancer and adenoma.Results: Test specificity was 99.3% with Hemoccult and was 92.7%, 94.7%, and 97.3% with HemoQuant, depending on the cutoff point; differences between Hemoccult and HemoQuant were significant when cutoffs of 1.5 and 2.0 mg/g were used in HemoQuant testing (6.6% [95% CI, 2.3 to 11.1] and 4.7% [CI, 0.8 to 8.5], respectively). Test sensitivity for colorectal cancer at all sites was 89.5% with Hemoccult and was 83.1%, 74.2% and 62.9% with HemoQuant, for the 1.5, 2.0, and 3.0 mg/g cutoffs, respectively; differences were significant with the 2.0 and 3.0 mg/g cutoff points (6.4% [CI, 6.7 to 24.0] and 26.6% [CI, 17.4 to 35.9%], respectively). The two tests had similar levels of sensitivity for cancers proximal to the splenic flexure, but sensitivity was substantially lower with HemoQuant for the more distal cancers. For all adenomas, test sensitivity was 30.2% with Hemoccult and ranged from 45.4% to 22.1% with HemoQuant.Conclusions: Although HemoQuant provides a precise measurement of fecal heme and its porphyrin degradation products, the test's performance characteristics in the detection of colorectal neoplasia are less satisfactory than those of Hemoccult II, a qualitative test for the presence of heme. [ABSTRACT FROM AUTHOR]

Background: Hemoccult II, the guaiac-based fecal occult blood test used in most colorectal cancer screening programs, has an unsatisfactory sensitivity for asymptomatic colorectal neoplasms. We evaluated the relative performance of four fecal occult blood tests, directed against various components of the hemoglobin molecule., Methods: All tests, Hemoccult II, HemoccultSENSA (a more sensitive guaiac test), HemeSelect (an immunochemical test specific for human hemoglobin), and HemoQuant (the heme-porphyrin assay), were performed by 107 patients with symptomatic colorectal cancer and 81 patients with predominantly asymptomatic adenoma. Hemoccult-SENSA and HemeSelect were performed by 1,355 screenees., Results: HemeSelect and Hemoccult-SENSA had significantly higher sensitivity for colorectal cancer (97% and 94%, respectively) than the other tests. HemeSelect had the highest sensitivity for adenomas; in 45 patients with large (> or = 10 mm) adenomas, sensitivity was 76% for HemeSelect, 60% for HemoccultSENSA, and 42% for both Hemoccult and HemoQuant. In the screenees, estimated specificity was 97.8% for HemeSelect and 96.1% for Hemoccult-SENSA., Conclusions: HemeSelect and Hemoccult-SENSA have the highest levels of sensitivity for detection of colorectal neoplasia, but the immunochemical test HemeSelect provides the best combination of specificity and sensitivity.

Expression of brush border hydrolases can reflect the state of differentiation of an epithelium. To determine if expression of these enzymes is disordered in patients with neoplastic or hyperplastic lesions, the activities of alkaline phosphatase, maltase, and dipeptidyl peptidase IV were measured spectrophotometrically in colonoscopic biopsies from the proximal and distal colon and rectum in 50 controls, 17 patients with large bowel adenomas, 29 with carcinoma, and 9 with hyperplastic polyps. In normal controls, a descending cecorectal gradient of alkaline phosphatase activities and an ascending gradient of maltase activities were seen (P < 0.001). Though regional patterns of expression were generally preserved in disease groups, there were significant differences of activities across patient groups for alkaline phosphatase (greater in cancer, adenoma, and hyperplastic groups than in normals; P < 0.05) and for dipeptidyl peptidase IV (greater in hyperplastic polyp group than normals, greater in adenoma than cancer group; P < 0.05). Compared with normal controls, abnormalities of site-specific activities were confined to the rectum in patients with adenoma (maltase decreased, P = 0.02; dipeptidyl peptidase IV increased, P < 0.01) or with carcinoma (alkaline phosphatase increased, P = 0.03) but dipeptidyl peptidase IV activities were increased in all regions in bowels bearing hyperplastic polyps (P < 0.01). These data suggest that neoplastic and hyperplastic lesions, while focal in nature, occur in large bowel epithelium, which is diffusely abnormal in terms of its expression of these enzymes.

Objective: To compare the readability and sensitivity of a new guaiac faecal occult blood test, HemoccultSENSA, with those of a standard guaiac-based test, Hemoccult, in a normal working environment., Design: The two tests were performed in parallel on routine clinical and contrived faecal specimens; those developing the tests were blinded as to the test type., Setting: All tests were carried out in the hospital ward environment under normal conditions by nurses working in the ward., Samples: Fifty faecal samples from healthy volunteer subjects (low concentrations of haemoglobin were added to 40 of these samples) and 145 faecal samples from 65 inpatients likely to have gastrointestinal bleeding., Main Outcome Measures: Test positivity rate, and graded measures of colour intensity, colour stability and colour pattern., Results: With patients' samples, the new test gave a greater number of positive results than the standard test (73.1% v. 65.5%; 95% confidence interval of the difference, 3.3%-11.9%). With contrived samples, the blue colour produced during development was more intense (P less than 0.0003), more stable (P less than 0.0025) and covered a larger area (P less than 0.01) with the new test compared with the standard test., Conclusions: These results demonstrate the better readability and slightly higher sensitivity of the new test. They justify its use in the ward environment or doctor's office. Patients being tested should consume a low peroxidase diet until the specificity of the new test has been fully evaluated.

A prospective controlled study of the safety of various catheter dressing protocols was carried out in 168 patients receiving parenteral nutrition via an infraclavicular central venous catheter. Four protocols were compared: 36 patients received gauze dressings changed three times per week; 31 received OpSite dressings changed every 7th day (OpS-7), 32 received OpSite changed every 10th day (OpS-10), and 69 received OpSite changed twice weekly (OpS-ICU). Mean duration of parenteral nutrition was approximately 2 weeks and all groups were well matched except that OpS-ICU patients suffered more frequently from an acute illness. Catheter-related sepsis was identified by clinical signs of systemic sepsis, positive peripheral venous blood and catheter-tip cultures and/or defervescence of fever after catheter removal. Catheter-related sepsis rates were low in all groups: 1/36 for Gauze, 0/31 for OpS-7, 1/32 for OpS-10, and 2/69 for OpS-ICU. Septicemia attributable to causes apart from catheter sepsis occurred in two, two, three, and four patients, respectively. Bacterial colonization of skin beneath OpSite was no more common in the OpS-10 than in the other groups. Signs of inflammation at catheter insertion sites were common in all groups but did not relate closely to skin colonization. OpSite can be safely applied to central venous catheters inserted under strict aseptic conditions, even in patients with open septic drainage. Dressings can be left in place for 7 days with a margin of safety lasting to 10 days, thus saving on cost of materials and nursing time.