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PubMed1990

Evaluation of two commercial test kits for detection of occult blood in feces of dogs.

To evaluate the sensitivity and specificity of 2 commercial test kits for detection of occult blood in canine feces, various volumes of blood were administered to 6 dogs via orogastric tube. Blood volumes tested were chosen on the basis of hemoglobin quantities of 5, 10, 20, 200, 350, and 500 mg of hemoglobin/kg of body weight. Fecal specimens were collected twice daily and analyzed separately by 2 observers for the presence of occult blood by use of modified guaiac and orthotolodine tablet tests, and for melena by visual inspection. Five dogs given blood at the rate of 500 mg of hemoglobin/kg and 1 dog given blood at the rate of 350 mg of hemoglobin/kg developed melena. Results of both occult blood tests were positive in 2 of 6 dogs given blood at the rate of 5 mg of hemoglobin/kg. Five of 6, and 4 of 6 dogs given blood at the rate of 10 mg hemoglobin/kg had positive test results by modified guaiac and orthotolodine methods, respectively. Results of both methods were positive in all dogs given blood at the rate of 20 mg of hemoglobin/kg. There was 86% agreement between the 2 observers' results for the modified guaiac method, and 78% agreement for the orthotolodine method. There was 77% agreement of results between the 2 test methods. Gastrointestinal transit time decreased with increasing volumes of blood. Occult blood testing was found to be useful for detection of blood in feces at volumes 20 to 50 times less than that required to cause melena.

Animals↗
PubMed1992

Preoperative testing for fecal occult blood: a questionable practice.

The benefit of fecal occult blood testing (FOBT) in patients without gastrointestinal symptoms who are hospitalized for an elective surgical procedure is uncertain. To resolve this issue, we analyzed the costs and benefits of preoperative FOBT by the model of a decision tree. In 2- and 3-way sensitivity analyses, the costs of diagnostic and therapeutic procedures and the probabilities of their various outcomes are varied simultaneously so that we might study their joint influence on the outcome of the decision analysis. The decision analysis shows that preoperative FOBT is associated with a smaller benefit than would be its omission. The higher cost and lower net benefit of preoperative FOBT reflect the impact of false-positive tests for occult blood. False-positive FOBT leads to expenditures for negative gastrointestinal work-ups, increased procedural costs, and a diminished rate of success for the elective surgical procedure, by delaying it. This outcome of the analysis is insensitive to large variations in the costs and probabilities built into the model. We conclude that screening for fecal occult blood provides no benefit if done routinely in patients who are hospitalized for any major surgical procedure.

Cost-Benefit Analysis↗
PubMed2003

A sensitive guaiac faecal occult blood test is less useful than an immunochemical test for colorectal cancer screening in a Chinese population.

BACKGROUND: Colorectal cancer screening by guaiac faecal occult blood test has been shown to reduce the incidence and mortality of colorectal cancer in Western populations. The optimal faecal occult blood test, whether guaiac or immunochemical, for colorectal cancer screening in the Chinese population remains to be defined. AIM: To compare the performance characteristics of a sensitive guaiac-based faecal occult blood test (Hemoccult SENSA) and an immunochemical faecal occult blood test (FlexSure OBT) in a Chinese population referred for colonoscopy. METHODS: One hundred and thirty-five consecutive patients who were referred for colonoscopy and who met the study inclusion criteria took samples for the two faecal occult blood tests simultaneously from three successive stool specimens, with no dietary restrictions. All tests were developed and interpreted by a single experienced technician who was blind to the clinical diagnosis. The sensitivity, specificity and positive predictive value for the detection of colorectal adenomas and cancers were estimated for the two tests. RESULTS: The sensitivity, specificity and positive predictive value for the detection of significant colorectal neoplasia (adenomas > or = 1.0 cm and cancers) were 91%, 70% and 18% for Hemoccult SENSA and 82%, 94% and 47% for FlexSure OBT. The specificity and positive predictive value were significantly higher for FlexSure OBT than for Hemoccult SENSA (P < 0.001 and P = 0.016, respectively). Combining the positive results from both faecal occult blood tests did not improve the accuracy. CONCLUSION: The positive predictive value of the immunochemical faecal occult blood test for the detection of significant colorectal neoplasia was 29% better than that of the sensitive guaiac-based test. This may relate to the Chinese diet and requires further study. The poor specificity of the sensitive guaiac-based test, without dietary restriction, makes it less useful for colorectal cancer screening in a Chinese population.

Adult↗
PubMed1989

Comparison of home occult blood tests and interaction of tests with ibuprofen.

The interaction of ibuprofen with home tests for occult blood was evaluated, and the accuracy of these tests was determined by validating the results with a specific quantitative assay of stool blood. Three home occult blood tests were evaluated: Early Detector, Fleet Detecatest, and CS-T Coloscreen Self Test. Fourteen men 19 to 35 years of age were instructed on how to use the tests and to record each day their dietary intake and stool consistency, the color of test control areas, the results, and the times of ibuprofen administration. The study consisted of a control period (days 0-5) and short-term (days 6-9) and long-term (days 10-14) ibuprofen periods. Each subject took two 200-mg tablets of ibuprofen three times daily beginning on day 6 and ending on day 14. During each study period, one stool sample was collected on each of three consecutive days. All three tests were performed on each sample, in addition to specific quantitative analysis with HemoQuant. All samples in the control period were negative for occult blood. Three positive results were reported by subject 4 in the short-term ibuprofen period, one with Fleet Detecatest and two with Early Detector. Subject 6 reported two positive Fleet Detecatest results and three positive Early Detector results during the long-term drug period. No positive results were detected with CS-T Coloscreen Self Test. The HemoQuant values showed that Early Detector produced one false-negative and two false-positive results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

Immunochemical fecal occult blood test is not suitable for diagnosis of hemorrhoids.

PURPOSE: This study was conducted to clarify the diagnostic value of an immunochemical fecal occult blood test for hemorrhoids. PATIENTS AND METHODS: In a case-control study, an immunochemical fecal occult blood test with a 2-day method was carried out on 82 subjects with hemorrhoids, on 82 subjects with colorectal cancer, and on 82 healthy subjects. In a population-based cross-sectional study, 29,714 subjects who received an immunochemical occult blood screening with a 2-day method were divided into two groups, according to the results of a questionnaire on hemorrhoids, and the positivity rate of an immunochemical test as well as the predictive value for colorectal cancer were compared in the two groups. Moreover, both an immunochemical occult blood test with a 2-day method and colonoscopy were conducted at the same time on asymptomatic subjects during a medical checkup. RESULTS: In the case-control study, the test was positive in 13.4% subjects with hemorrhoids, in 84.1% subjects with colorectal cancer, and in 4.9% healthy subjects, respectively, showing a significant difference in the detection rate between the two diseases (P < 0.001). In the population screening program, the test was positive in 6.9% subjects with hemorrhoids and in 6.5% subjects without hemorrhoids, and the predictive value was 3.2% in subjects with and without hemorrhoids, respectively, indicating no significant difference in the positivity rate as well as the predictive value between the two groups. Among 232 subjects in a medical checkup, 28 patients with hemorrhoids and 21 patients with colorectal polyp 1 cm or larger were diagnosed by colonoscopy, and the occult blood test was positive in 16.7% patients with hemorrhoids and in 52.4% patients with colorectal polyp, respectively. There was a significant difference in the sensitivity between the two disease groups (P < 0.05). CONCLUSIONS: These findings indicate that the immunochemical fecal occult blood is unsuitable for the diagnosis of the patients with hemorrhoids and an examination of the colorectum is necessary in cases where the occult blood test is positive but there is a sign of hemorrhoids.

Aged↗
PubMed2006

Many participants in fecal occult blood test population screening have a higher-than-average risk for colorectal cancer.

OBJECTIVES: Population-based colorectal cancer screening by fecal occult blood testing reduces cancer-specific mortality. Current guidelines recommend this strategy for average risk individuals. This study investigated the prevalence of higher-than-average risk characteristics, and rate of prior colonoscopy, in participants in fecal occult blood test screening programs. METHODS: Randomly selected individuals aged 50-74 years in urban Adelaide were offered free fecal occult blood test screening by mail, without prior knowledge of their medical status. Each invitation included a questionnaire to record the prevalence of higher-than-average risk characteristics related to symptoms, family history or comorbidity, as well as prior colonoscopy. The definition of average risk was taken from updated guidelines published by the US Multisociety Task Force on Colorectal Cancer. RESULTS: Of 2538 responses analyzed, 425 individuals had had a colonoscopy within the last 5 years, 106 fulfilled family history criteria for an initial screening colonoscopy, 209 had past polyps and 26 had had colorectal cancer. Eighty-three reported recent rectal bleeding. By current guidelines, 23% of the screened population did not warrant fecal occult blood test, because either prior colonoscopy rendered it unnecessary or particular patient characteristics made colonoscopy a more appropriate initial investigation. CONCLUSIONS: Fecal occult blood test screening programs capture a sizeable number of higher-than-average risk individuals that may warrant colonoscopic rather than fecal occult blood test screening. Other participants have had a recent colonoscopy and probably warrant a delay in screening. Mass population fecal occult blood test-based screening programs need to more effectively target those at average risk and should divert those of higher or lower risk to more individualized assessment.

Aged↗
PubMed2004

Digital rectal fecal occult blood screening during gynecologic examination.

OBJECTIVE: The purpose of this study was to test the feasibility of digital rectal fecal occult blood screening during pelvic examination. STUDY DESIGN: We reviewed the data for 232 consecutive women who underwent digital rectal fecal occult blood screening during routine pelvic examination and who had had at least 1-year of follow-up visits: 59% of the women were followed for gynecologic cancer, and 41% of the women were followed for benign gynecologic disease. The median age was 62 years. Patients with positive digital rectal fecal occult blood screening were sent for gastroenterologic examination. RESULTS: Sixteen of 232 patients (7%) had a positive digital rectal fecal occult blood screening result. On gastroenterologic examination, 5 of the 16 patients (31%) were found to have disease (2 polyps, 1 diverticular disease, 2 radiation proctitis). At 1-year follow-up, no patient had colon cancer. CONCLUSION: Until better compliance can be obtained with home stool sample fecal occult blood testing, we recommend a larger study of digital rectal fecal occult blood screening during gynecologic examination to verify our results.

Aged↗
PubMed1992

Comparison of fecal occult blood tests for detection of gastrointestinal bleeding in pediatric patients.

To compare fecal occult blood tests (Hemoccult II, Hemoccult SENSA, HemeSelect) for detecting the presence of occult gastrointestinal bleeding in a pediatric population at high risk, we analyzed stool specimens from 100 children who followed a restricted diet. Forty-two children had upper and 58 lower gastrointestinal sources of bleeding. Positivity rates ranged from 10.8% to 26% dependent upon the occult blood test. Whereas Hemoccult II and Hemoccult SENSA slides detected several positive specimens in upper gastrointestinal bleeding sources, all HemeSelect slides were negative in these subjects. In lower gastrointestinal bleeding, HemeSelect slides were positive in 26.8% of samples as opposed to 15.9% and 17.5% positivity rates for Hemoccult II and Hemoccult SENSA, but this difference was not statistically significant. We conclude that fecal occult blood tests vary, depending upon the origin of bleeding. Our results favor use of Hemoccult SENSA slides for suspected upper gastrointestinal bleeding and HemeSelect slides for lower gastrointestinal bleeding in children. However, if only one all-purpose fecal occult blood test is to be utilized, then our data supports the use of Hemoccult SENSA slides for children.

Adolescent↗
PubMed2006

[Clinical usefulness of fecal occult blood test as a screening method for asymptomatic patients with colon polyps].

BACKGROUND/AIMS: Detection of asymptomatic benign colon polyp is increasing because colonoscopy is widely used as a screening and diagnostic method. Fecal occult blood test is usually performed for the selection of patients requiring colonoscopy as well as mass screening for colon cancer. The aim of this study was to investigate the usefulness of fecal occult blood test performed prior to colonoscopy as a screening method of benign colon polyps. METHODS: Clinical characteristics of patients with polyps were evaluated according to the fecal occult blood test results in patients who underwent one-day fecal occult blood test and colonoscopic polypectomies from May 2003 to October 2004, retrospectively. RESULTS: A total of 942 colonoscopic polypectomies in 288 patients were evaluated. Fecal occult blood tests were positive only in 32 patients (11.1%). In univariate analysis, there was a significant difference in polyp size (p=0.02) and location (p=0.03) according to the presence of positive fecal occult blood tests. In addition, age of the patient (p=0.046), polyp size (mean, p=0.04; largest, p<0.01) and the number of polyps (p=0.045) were significantly different. However, in multivariate analysis, only polyp size larger than 20 mm was significantly related with positive fecal occult blood test with estimated odds ratio of 4.71. CONCLUSIONS: Fecal occult blood test has limitations as a screening test in asymptomatic patients with colon polyps, except for colon polyps larger than 20 mm in size.

Colonic Neoplasms↗
PubMed1994

Accuracy of immunological fecal occult blood testing for colorectal cancer screening.

BACKGROUND: The present study was carried out to assess the accuracy of immunological fecal occult blood testing as a means for colorectal cancer screening. METHODS: Two hundred patients with colorectal cancer and 100 healthy controls served as subjects of the study. A total of 300 subjects were tested by immunological and chemical fecal occult blood tests. As a further test of diagnostic accuracy, mass screening for colorectal cancer using immunological fecal occult blood testing was conducted on 3,365 residents within the Nagano prefecture, and all of the subjects were followed for 1 year through verification from cancer registration of colorectal cancer patients. RESULTS: Sensitivity and specificity of immunological fecal occult blood testing were 67 and 96%, respectively, values significantly higher than those obtained by chemical fecal occult blood testing. Also, sensitivity and specificity in mass screening were 91 and 96%, respectively, indicating an accuracy higher than that achieved by chemical occult testing. CONCLUSION: These findings suggest that immunological fecal occult blood testing is a useful strategy for colorectal cancer screening.

Colorectal Neoplasms↗
PubMed1996

Occult blood versus fecal leukocytes in the diagnosis of bacterial diarrhea: a study of U.S. travelers to Mexico and Mexican children.

A study was done to test the effectiveness of fecal occult blood as a screening test for invasive bacterial pathogens and as a substitute for the fecal leukocyte examination in adult and pediatric cases of acute diarrhea. United States citizens studying in Mexico and Mexican children, both with acute diarrhea had their stools cultured, examined for fecal leukocytes, and tested for occult blood. Using culture results as the criterion standard for detection of bacterial agents, and fecal leukocytes for diarrhea associated with diffuse colonic inflammation, occult blood was tested for its sensitivity, specificity, and predictive value using 2 x 2 tables. Analysis of the data found that occult blood negative samples were reliable indicators of a lack of invasive bacteria in both adult and pediatric patients (negative predictive values of 87% and 96%, respectively). Positive results for either test were not reliably predictive as indicators of invasive bacteria among adults. A positive occult blood test result was significantly more sensitive than a positive fecal leukocyte test result (79% versus 42%) in detecting invasive bacteria in the pediatric patients; however, the positive predictive value was only 24%. The fecal occult blood test is an uncomplicated, low-cost test that was reliable when giving a negative result in detecting a lack of invasive bacteria in adult and pediatric patients with diarrhea. In children, a positive result on a fecal occult blood test is sensitive but not specific in detecting invasive bacterial enteropathogens. These data also indicate that a commercially available test for occult blood represents a suitable alternative to microscopic examination of fecal samples for leukocytes obtained from patients with acute diarrhea.

Acute Disease↗
PubMed2001

Does stool collection method affect outcomes in immunochemical fecal occult blood testing?

PURPOSE: This paper compares the positive predictive value of an immunochemical fecal occult blood test for colorectal neoplasms between the stool specimens obtained during the digital rectal examination and those obtained during the routine screening. METHODS: In a medical check-up, 1,688 subjects received both an immunochemical fecal occult blood test and a colonoscopy. Fecal occult blood was tested by two methods: digital rectal examination and routine screening. The positivity rate of an immunochemical fecal occult blood test and the positive predictive value for colorectal cancer and large adenomatous polyp were determined by these two methods. RESULTS: The positivity rate and the positive predictive value were 5.4 percent and 19.8 percent (4.4 percent for cancer and 15.4 percent for adenomatous polyp) in the digital rectal examination method and 3.5 percent and 27.1 percent (6.8 percent for cancer and 20.3 percent for adenomatous polyp) in the routine screening method, respectively. These figures indicate a significant difference in the positivity rate (P < 0.01) and the positive predictive value (P < 0.05) between these two methods. CONCLUSIONS: These findings indicate that the stool obtained by routine screening has a better positive predictive value than stool collected during the digital rectal examination.

Adult↗
PubMed1985

Screening for colorectal cancer: the rationale and a recent advance in the detection of fecal occult blood.

For the very first time, an occult blood test has been designed to conform to convenient and natural bathroom habits. For the very first time, we therefore expect the general public to agree willingly to participate in occult blood testing. For the very first time, we expect Early Detector to successfully screen the general public, so that survival rates from colon and rectal cancer may show a significant improvement in the next decade.

Colonic Neoplasms↗
PubMedDate not supplied

Fecal occult blood screening for colorectal cancer.

We critically analyzed the current literature on fecal occult blood testing as it pertains to colorectal cancer screening. We used articles published or referenced in the major English-language medical and gastroenterology journals for the last 10 years. Large, randomized controlled trials, case-control and cohort studies, and other sources containing information pertinent to the application of fecal occult blood testing for colorectal cancer screening were selected. Although the fecal occult blood test results are capable of predicting the presence of colorectal cancers and polyps, the sensitivity is variable in different studies and low for the latter. Nevertheless, most reports of its use emphasize that a relatively high percentage of the cancers detected are early-stage lesions. Currently available methods for colorectal cancer screening are imperfect, thereby increasing the cost-effectiveness ratio. The fecal occult blood test remains a workable approach to reducing the mortality from colorectal cancer provided it is carried out with attention to important variables such as the need for compliance, including the compliance of physicians.

Colonoscopy↗
PubMed1999

Limitations of the faecal occult blood test in screening for colorectal cancer.

BACKGROUND: A screening test should be acceptable, safe, simple, accurate, reliable, effective, and inexpensive. Screening for colorectal cancer with the faecal occult blood test is done to reduce the incidence and mortality from colorectal cancer. How does this test measure up to these requirements? METHODS: The characteristics of faecal occult blood test are described by means of clinical epidemiology, analysing its compliance, sensitivity, specificity, positive predictive value, and its test performance in Bernoulli trials. A decision tree and a Markov model are used to compare the cost-effectiveness of screening strategies involving faecal occult blood test and colonoscopy. RESULTS: After 5-10 years, patient compliance in a faecal occult blood test screening programme falls below 50%. Over 80% of the patients are likely to leave the programme before its completion. Although the test itself may seem safe and simple, the high rate of false-positive outcomes exposes many subjects to the potential complications of colonoscopy. The high rate of false-negative tests gives patients with colorectal cancer a false sense of security and delays their proper diagnostic work-up. In populations with low prevalence rates of colorectal cancer, faecal occult blood test becomes very inaccurate in diagnosing colorectal cancer, as its positive predictive value falls below 5%. Its long-term test performance is unreliable in that it comes to depend on the frequency, with which the test is repeated. Any negative or positive test result can be achieved by varying the frequency of test repetition. Screening by colonoscopy every five or ten years is more cost-effective than screening by annual faecal occult blood test in preventing the occurrence of colorectal cancer and its associated mortality. CONCLUSIONS: Screening strategies for colorectal cancer involving faecal occult blood test should be abandoned.

Colonoscopy↗
PubMed1984

Detection of occult blood in gastric juice.

The detection of occult blood in gastric fluid samples may be clinically important, but many current methods are too sensitive. Gastric fluid containing various concentrations of blood were subjected to analysis by four screening methods. Orthotolidine based tests (Hematest reagent tablets and Bili-Labstix) designed for urinary and fecal blood detection when applied to gastric aspirates were highly accurate, but sensitivity was so great that normal fluid yielded positive results. Guaiac slide tests (Hemoccult and Gastroccult slide tests) were less sensitive than the orthotolidine-based tests. The Hemoccult slide test was influenced by the low pH of gastric aspirates and neutralizing the acidity of the gastric fluid by addition of NaOH improved the sensitivity of the method. The Gastroccult slide test accurately determined gastric fluid pH and hemoglobin concentration greater than 300 micrograms/dl in the acid environment of gastric fluid. The Gastroccult slide test is a simple, rapid, and convenient method for initial evaluation of patients suspected of occult blood in gastric juice.

Gastric Juice↗
PubMed1997

Incidence of visible and occult blood on laryngoscope blades and handles.

Anesthesia providers must take appropriate precautions to reduce the potential for transmission of infectious agents to the patients under their care. The devastating spread of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) over the past decade has resulted in the development of specific guidelines for the cleaning, disinfection, sterilization, and handling of medical equipment and instruments. Contamination of laryngoscope blades and handles with visible and occult blood frequently occurs during routine airway management. Several studies suggest procedures for cleaning, disinfection, sterilization, or handling of laryngoscope blades and handles are ineffective, or there may be poor compliance with the established protocols. The purpose of this study was to determine the incidence of visible and occult blood on laryngoscope blades and handles that were identified as ready for patient use. Sixty-five laryngoscope blades and handles identified as ready for patient use were observed for visible blood and tested for occult blood. A modified version of the three-stage phenolphthalein blood indicator test was employed to determine the presence of occult blood. None of the blades or handles observed had visible blood. Of the 65 blades tested for occult blood, 13 (20%) tested positive. Of the 65 handles tested for occult blood, 26 (40%) tested positive. More afternoon blades and handles tested positive for occult blood than morning blades and handles (P < 0.01). The extent to which contaminated anesthesia equipment plays in nosocomial infection is difficult to determine. The presence of blood is an indicator of potential cross-infection, since biological fluids, such as blood and saliva, are known to transmit infectious diseases. This study confirms that more rigorous decontamination protocols must be instituted to ensure complete removal of blood prior to sterilization, since laryngoscope blades and handles have irregular surfaces with repositories for infectious material.

Anesthesia↗
PubMed1983

Participation in faecal occult blood screening for colorectal cancer.

Chemical faecal occult blood testing has been proposed as a means of screening for colorectal cancer (C.C.) in populations or in identified high-risk groups. The level of public participation is a critical factor in the effectiveness of screening programmes. This study was conducted as a methodological pretest for an intended investigation of factors influencing screening participation. Faecal occult blood screening was offered to 728 employees of a teaching hospital in Sydney, New South Wales and 41% participation was obtained. Both participants and non-participants were questioned on demographic and social background factors, on their experience of C.C. in others, and on their reasons for participating or not participating. Major reasons for participation were: a general feeling of the importance of health checks and screening tests; a belief that it is important to diagnose C.C. early; and the fact that the test was simple and easy to do. Prominent self-acknowledged reasons for non-participation were indifference, procrastination, absence of previous bowel complaints, preference for one's own doctor to do such tests and inconvenience or lack of time. Those more likely to participate were: females; those of Australian or British origin; single, separated or divorced persons; those having two or more dependents and those with personal knowledge of a C.C. patient.

Attitude to Health↗