A comparative study of eight fecal occult blood tests and HemoQuant in patients in whom colonoscopy is indicated.

BACKGROUND AND OBJECTIVE: Some studies suggest that immunochemical fecal occult blood tests (FOBTs) and HemoQuant are more efficient at detecting fecal occult blood than the commonly employed Hemoccult II (guaiac) test. We undertook this study to determine whether an immunochemical test either alone or in combination with a guaiac test gives efficiency superior to the Hemoccult II test in predicting significant gastrointestinal tract disease. DESIGN: Criterion standard, prospective, blinded. SETTING: Referral population of ambulatory patients at an institutional and a private hospital. PATIENTS: Eight-one patients referred to a gastroenterologist and in whom colonoscopy was indicated. INTERVENTIONS: While on a restricted diet, patients made preparations for FOBTs from three consecutive bowel movements. Patients then underwent colonoscopy. Polyps larger than 1 cm in size, carcinoma of the colon, peptic ulcers, gastric erosions, and angiodysplasia were considered to be likely causes of occult gastrointestinal tract bleeding. MAIN OUTCOME MEASURES: Using colonoscopy results as the reference standard, sensitivity, specificity, and positive and negative predictive values for each of eight tests or pair of tests were compared with those of Hemoccult II. RESULTS: Of 81 patients, 10 had significant lower gastrointestinal tract lesions and six had significant upper gastrointestinal tract lesions. Hemoccult SENSA, Heme-Select, and FECA-EIA were shown to be more sensitive than Hemoccult II but slightly less specific. Paired tests showed less efficiency than Hemoccult II alone. CONCLUSIONS: We did not find an ideal test or pair of tests; however, Hemoccult SENSA exhibited higher sensitivity than Hemoccult II and many other tests. The sensitivity, specificity, and positive predictive values of many of the FOBTs were believed to be low. We recommend that physicians consider FOBTs only as adjuncts to history and physical examination findings in deciding how to proceed in diagnosing gastrointestinal tract disease.

A comparative study of fecal occult blood tests for early detection of gastrointestinal pathology.

The question of what the most accurate and efficient fecal occult blood testing method is for the early detection of pathological gastrointestinal tract bleeding continues to be intensely debated. In this prospective study, the following five uniquely different slide tests were investigated in 120 patients who underwent gastrointestinal tract investigation: (1) a combination monoclonal antibody guaiac test (Monohaem); (2) an immunologic assay, enzyme-linked immunosorbent assay, with (3) a highly sensitive guaiac test (Fecatwin S/Feca enzyme immunoassay), (4) a popular guaiac test (Coloscreen III) (comparable with Hemoccult II), and (5) Coloscreen III/VPI (ie, with vegetable peroxidase) inhibitor. Computerized data show efficiency values for detection of fecal occult blood by Coloscreen III-Fecatwin S-Monohaem combined, 93%; Coloscreen III-Monohaem combined, 91%; Monohaem, 87%; Coloscreen III/VPI, 82%; Coloscreen III, 79 percent; enzyme-linked immunosorbent assay, 77%; and Fecatwin S, 68%. Results of sensitivity, specificity, false-positive and false-negative test results, tests' predictive value, simplicity, and costs of tests in this clinically based study suggests that the concomitant use of the monoclonal, monospecific test for human hemoglobin and an appropriately sensitive guaiac test is a potentially valuable approach to mass screening and early detection of occult bleeding gastrointestinal tract pathology, including colorectal cancer.

New screening method for occult gastrointestinal bleeding: immunologic and guaiac slide tests.

A valid mass screening method for occult, bleeding gastrointestinal pathology including colorectal cancer should be monospecific for human hemoglobin, sensitive for approximately 3 mg of human blood per 1 g of stool, capable of differentiating upper and lower gastrointestinal bleeding, cost effective, uncomplicated, and acceptable to patients. Hemoccult II, a guaiac peroxidase detection test, is nonspecific for human blood and cannot differentiate between upper and lower gastrointestinal bleeding. A radial immunodiffusion slide test for detecting human hemoglobin was compared with a guaiac test over a four-year period in 211 patients. in gastrointestinal problems diagnosed by endoscopy, roentgenographic rays, and other procedures, the Hemoccult II was positive in 9 of 41 cases of upper gastrointestinal tract origin (21 percent detection rate), whereas the radial immunodiffusion method, expected to be negative as a result of action of gastrointestinal proteases, was positive in only 3 and negative in 38 of the 41 samples (92 percent accuracy). The two tests were equally effective in detecting lower gastrointestinal bleeding (14 of 37 samples, 37 percent accuracy). The findings of this study indicate that the immunologic test may remedy the deficiencies of the guaiac test. The concomitant use of the immunologic and appropriately sensitive guaiac test appears to fulfill screening test requisites.

Maternal zinc, iron, folic acid, and protein nutriture and outcome of human pregnancy.

Four hundred fifty women were observed during pregnancy and postpartum. Forty-three variables including 12 laboratory indices of maternal nutrient status were assessed. Of the variance in fetal weight and head circumference 9.9 and 8.1%, respectively, were predictable by polynomial stepwise regression of laboratory indices of maternal nutriture. Maternal plasma zinc levels were inversely correlated with fetal weight. The occurrence of pregnancy complications in the highest and lowest quartiles of maternal plasma zinc, albumin, iron, and folic acid were compared. Using data only from the initial blood samples for which the trimester was identified precisely (n = 394), a significant association was found between the total occurrence of fetomaternal complications and zinc and albumin levels in the lowest quartile (zinc, p less than 0.02; albumin, p less than 0.02). Low zinc or low albumin were also associated with the specific complications of fetal distress (zinc, p less than 0.002; albumin p less than 0.002). High plasma folate was also associated with the total occurrence of complications (p less than 0.008) and with fetal distress (p less than 0.002). When all data (n = 713) including repeat blood samples and data from 56 mothers in whom the trimester could not be verified precisely were evaluated, associations between other complications and lowest quartile zinc and albumin and highest quartile folate were identified. Discriminant analysis of data from the initial blood samples revealed that plasma zinc was a discriminator for fetomaternal complications only in women in the lowest quartile for plasma zinc.