Prospective evaluation of the use and outcome of admission stool guaiac testing: the Digital Rectal Examination on Admission to the Medical Service (DREAMS) Study

BACKGROUND: Although physicians often perform fecal occult blood testing at the time of hospital admission, the practice of admission stool guaiac (ASG) testing has not been evaluated prospectively. The aim of this study was to determine the frequency and outcomes of digital rectal examination (DRE) and ASG testing in patients admitted to the hospital. METHODS: We prospectively evaluated 2143 patients admitted to the medical service at our hospital over a 1-year period. A detailed clinical history was obtained, and the proportion of patients who had DRE and ASG testing, the frequency of positive tests, and the results of follow-up testing were determined. RESULTS: A DRE was performed in 1539 of the 2143 subjects (71.8%), and 1.8% had abnormal findings, 21.8% had a normal examination, and the result of ASG testing was the only documented finding in the remaining 76.4% of patients. ASG testing was performed in 1342 of the 2143 subjects (62.6%), and the ASG test was positive in 237 persons (17.7%). However, only 161 (67.9%) of those with a positive ASG test had further diagnostic testing and a colonic source of occult gastrointestinal blood loss was detected in 68 (42.2%) of these 161 persons. CONCLUSIONS: Although DRE and ASG testing are commonly performed on admission to the hospital, documentation of the findings and follow-up of positive tests are poor. These findings highlight the need to improve physician training on the appropriate use and documentation of the DRE and fecal occult blood testing.     

A new immunological test strip device for the rapid,qualitative detection of faecal occult blood

OBJECTIVE: Guaiac tests for faecal occult blood are still the most commonly performed screening procedure for colorectal cancer. Because both sensitivity and specificity of faecal occult blood testing are critical to cost-effective colorectal cancer screening programs, we investigated a rapid immunological test strip device for bedside detection of faecal occult blood. METHODS: Stool specimen from 100 patients were chosen for this study based on the presence (n = 50) or absence (n = 50) of faecal occult blood as measured with a human haemoglobin ELISA (cut-off level 相似文献   

The utilization of fecal occult blood testing in the institutionalized elderly

OBJECTIVE: To examine physician use of stool guaiac testing in order to determine indications for testing, how the test was used, and the consequences of a particular test result. DESIGN: Retrospective case series. SETTING: Large midwestern inpatient nursing home facility. PATIENTS: All patients with positive fecal occult blood tests (FOBT) and one-third of patients with negative FOBT. RESULTS: In an 18-month period, 916 occult blood tests were performed on 339 patients (37% of the nursing home census). Patients over age 90 were as likely to receive FOBT as those under age 70. Fourteen percent of those tested had at least one positive test. Fifty-eight percent of the patients with positive tests underwent no additional diagnostic testing. No cause for the positive FOBT was found for 68% of patients receiving the test for routine screening. Physician estimates of how frequently they employed FOBT for these patients correlated very poorly with their actual practices (r = .17). CONCLUSION: There is a high prevalence of positive results from FOBT among nursing home patients. In most cases, such results do not cause a change of therapy or result in additional workup. Lack of information on the role of FOBT in nursing home patients contributes to the great diversity in utilization of this test by nursing home physicians.     

Immunological Testing for Occult Blood in Patients with Acute Infectious Diarrhea (Can It Improve the Specificity of the Guaiac Test?)

Microscopic stool examination can distinguishinflammatory from noninflammatory diarrheas. Themodified guaiac test was shown to have good correlationto stool microscopy. In a prospective study we evaluated the diagnostic accuracy of a modified guaiactest (ColoRectal-Test, Roche) and of an immunologicaltest for fecal haemoglobin (Colo-Immun-Test, Roche) inrelation to the diarrheal pathogens identified and compared it with the stool microscopy. In 304patients, clinical presentation, stool microscopy, stoolculture, and modified guaiac test were recorded.Sensitivity of the guaiac test was 69% as compared to 63-67% for the stool microscopy. Specificitycould be improved by 10-15% using an immunological testto exclude false-positive guaiac reactions. A modifiedguaiac test can replace microscopic stool examination to distinguish between inflammatoryand noninflammatory diarrhea. Immunological testing foroccult blood can improve the specificity of the guaiactest, but is too elaborate to serve as a screening test. The modified guaiac test can easily behandled by community health workers and could beimportant in the diagnostic work-up for acute infectiousdiarrhea.     

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.     

Efficacy of the routine admission urinalysis

The clinical efficacy of routine admission urinalyses was evaluated in 301 patients admitted to the internal medicine wards of a university teaching hospital. Using a consensus analysis approach, three Department of Medicine faculty members reviewed the patients' charts to determine which tests were performed routinely and which test results led to diagnostic or therapeutic management changes. Of the 243 urinalyses performed, 123 (51 percent) were ordered routinely for patients without recognizable medical indications. Results of the routine urinalyses were abnormal in 42 (34 percent) of the patients and led to additional laboratory testing in 20 (16 percent) of the cases. However, the test results led to therapeutic changes in only three (2.4 percent) of the patients, and in two of these patients, the treatment instituted probably was unnecessary. It is concluded that the impact of routine admission urinalysis on patient care is very small and that there is little justification for ordering this test for all patients admitted to the hospital.     

Reliability of chemical tests for fecal occult blood in hospitalized patients

In 39 hospitalized patients with suspected gastrointestinal bleeding and given intravenous⁵¹Cr-labeled red cells, reactions of three chemical spot tests for fecal occult blood were compared with the true blood loss as determined by stool radioassay. Guaiac reagent and orthotolidine (Hematest^®) tablets were extremely sensitive, but yielded false-positive reaction rates of 72% and 76%, respectively on the 240 stool specimens compared. A modified guaiac test (Hemoccult^®) exhibited a false-positive rate of 12%. Of the 27 patients entering the study due to positive guaiac or Hematest screening tests, 17 (63%) were not bleeding. Hemoccult, approximately 1/4 as sensitive as guaiac and Hematest, could miss lesions with low rates of bleeding unless multiple stools were tested. While barium had no effect, iron therapy or laxatives tended to lower both false-positive and false-negative reactions for all reagents. A positive Hemoccult test usually indicated significant gastrointestinal bleeding and would appear to be the test of choice provided at least 3 stools are tested to minimize false-negative results.Supported by a Medical Investigatorship (Dr. Ostrow) and Gastroenterology Training Grant (Dr. Morris) from the U.S. Veterans Administration.     

Incidence of amebiasis in patients with positive guaiac test of the stool

Summary 1. Of 50 individuals who had a positive guaiac test of the stool after having been on a meat-free diet for 3 days or longer, only 1 (2 per cent) hadE. histolytica in the stool on a single examination.2. Since 2 per cent represents the predicted incidence of amebiasis in the general population of Strang Clinic patients (on examination of a single casual specimen), it was concluded that, in general, positive guaiac tests are not due to amebiasis.3. This does not preclude the possibility that in certain instancesE. histolytica may produce sufficient intestinal disease to be responsible for positive guaiac tests.Dr. Emerson Day, Director of the Strang Clinic, cooperated in these studies, and Dr. Louis Venet also offered valuable assistance.Mrs. Patricia Daniels, The Central Laboratories, The New York Hospital, examined the stool specimens. Miss Mary Sukany performed the guaiac tests on the stools.     

Survey of internal medicine residents' use of the fecal occult blood test and their understanding of colorectal cancer screening and surveillance

OBJECTIVE: Primary care physicians have imperfect understanding of current colorectal cancer screening guidelines and recommendations. Furthermore, compliance with colorectal cancer screening by internal medicine residents has been demonstrated to be poor. We sought to identify whether current trainees in internal medicine had adequate understanding of colorectal cancer screening and surveillance and test utilization. METHODS: We applied a structured questionnaire about colorectal cancer screening and the use of fecal occult blood tests to 168 internal medicine residents at four accredited programs in the U.S. They were also asked for recommendations about six hypothetical patients who may have been candidates for screening or surveillance. RESULTS: Seventy-one percent identified 50 yr as the currently recommended age to commence screening in an average-risk individual; 64.3% would begin screening with fecal occult blood testing and flexible sigmoidoscopy and 4.8% with colonoscopy. Most perform fecal occult blood testing on stool obtained at digital rectal exam and without prior dietary restrictions. Many use fecal occult blood testing for indications other than colorectal cancer screening. Only 29% recommended colonoscopy to evaluate a positive fecal occult blood test. Most residents plan to be screened for colorectal neoplasia at the appropriate age; significantly more opted for colonoscopy than recommended it for their patients. CONCLUSIONS: Internal medicine residents have many misperceptions regarding colorectal cancer screening and the utility of the fecal occult blood test. Educational efforts should be directed at internal medicine residents, many of whom plan careers in primary care, where most colorectal cancer screening is currently performed.     

Is there a preference for different ways of performing faecal occult blood tests?

Low compliance with faecal occult blood screening reduces the power of clinical trials, potential benefit, and efficiency. It has been proposed that the faecal manipulation required to perform conventional guaiac based tests may be an important factor in low compliance. The aim of this study was to evaluate whether use of a new method (vehicle) of stool collection for the faecal occult blood guaiac test would be preferred to the established standard. A novel self-interpreted test, Early Detector^® (ED), requires the subject to apply a guaiac/peroxide spray to a stool sample collected simply by wiping the anus with a specimen pad. To determine whether this method would be preferred to the stool manipulation required by Haemoccult^® (HO) and to compare test validity, employees at a London company were invited to use both tests. Eight-hundred and fifty-seven subjects were shown both tests. Before use, 48% indicated a preference for the method of Early Detector; 24% chose Haemoccult (p<0.001), while 28% indicated no immediate preference. Seven-hundred and one performed both tests. After use, 74% preferred ED; 5% preferred HO (p<0.001); 21% had no preference (NP). The preference for the ED test method was consistent by sex categories, age groups and occupational class. Logistics, aesthetics, and immediacy of results were the main reasons indicated for choosing ED. Whether the preference for ED could result in higher compliance remains to be proven. Its high positivity (14%), however, would preclude its use as a sole test to determine the need for endoscopic and/or radiologic investigation in the screened patient.     

A nine-year audit of open-access upper gastrointestinal endoscopic procedures: results and experience of a single centre

BACKGROUND:

The appropriateness and safety of open-access endoscopy are very important issues as its use continues to increase.

OBJECTIVE:

To present a review of a nine-year experience with open-access upper gastrointestinal endoscopy with respect to indications, diagnostic efficacy, safety and diseases diagnosed.

METHODS:

A retrospective, observational case series of all patients who underwent open-access endoscopy between January 2000 and December 2008 was conducted. Indications were classified as appropriate or not appropriate according to American Society of Gastrointestinal Endoscopy (ASGE) guidelines. Endoscopic diagnoses were based on widely accepted criteria. Major complication rates were assessed.

RESULTS:

A total of 20,620 patients with a mean age of 58 years were assessed, of whom 11,589 (56.2%) were women and 9031 (43.8%) were men. Adherence to ASGE indications led to statistically significant, clinically relevant findings. The most common indications in patients older than age 45 years of age were dyspepsia (28.5%) and anemia (19.7%) in the ASGE-appropriate group, and dyspepsia in patients younger than 45 years of age without therapy trial (6.6%) in the nonappropriate group. Of the examinations, 38.57% were normal. Hiatal hernia and nonerosive gastritis were the most common findings. Important diagnoses such as malignancies and duodenal ulcers would have been missed if endoscopies were performed only according to appropriateness. There were only two major complications and no mortalities.

CONCLUSIONS:

Open-access upper gastrointestinal endoscopy is a safe and effective system. More relevant findings were found when adhering to the ASGE guidelines. However, using these guidelines as the sole determining factor in whether to perform an endoscopy is not advisable because many clinically relevant diagnoses may be overlooked.     

Fecal occult blood testing as a diagnostic test in symptomatic patients is not useful: A retrospective chart review

BACKGROUND:

The fecal occult blood test (FOBT) is a screening tool designed for the early detection of colorectal cancer in primary care. Although not validated for use in hospitalized patients, it is often used by hospital physicians for reasons other than asymptomatic screening.

OBJECTIVE:

To profile the in-hospital use of the FOBT and assess its impact on patient care.

METHODS:

Patient charts were retrospectively reviewed for all FOBTs conducted over a three-month period in 2011 by the central laboratory supporting the three acute care campuses of Hamilton Health Sciences (Hamilton, Ontario).

RESULTS:

A total of 229 patients underwent 351 tests; 52% were female and the mean age was 49 years (range one to 104 years). A total of 80 (34.9%) patients had at least one positive test. The most common indications for testing were anemia (51.0%) and overt gastrointestinal bleeding (19.2%). Only one patient had testing performed for asymptomatic colorectal cancer screening. In only 20 (8.7%) cases medications were modified before testing and diet was modified in only 21 (9.2%) cases. Most patients (85.2%) were taking one or more medications that could result in a false-positive result. Only 18 (7.9%) patients had a digital rectal examinations documented, of which seven were positive. All patients with a positive digital rectal examination underwent endoscopic procedures that revealed a source of bleeding. Among 44 patients with overt gastrointestinal bleeding, 12 (27.3%) had endoscopic investigations delayed to await results of the FOBT. Four patients were referred despite a negative FOBT due to a high degree of suspicion of gastrointestinal bleeding.

CONCLUSIONS:

The FOBT is often used inappropriately in the hospital setting. Confounding factors, such as diet and medication use, which may lead to false positives, are often ignored. Use of the FOBT in-hospital may lead to inappropriate management of patients, increased length of stay and increased direct medical costs. Use of the FOBT should be limited to validated indications only.     

The ‘natural history’ of declined outpatient gastroenterology referrals

OBJECTIVE:

To evaluate the ‘natural history’ of outpatients who were referred to the Division of Gastroenterology at the University of Alberta Hospital (Edmonton, Alberta) for gastrointestinal problems and were subsequently declined.

METHODS:

Patients were tracked for 12 months after they were referred and declined for the following indications: abdominal pain, rectal bleeding, fecal occult blood test-positive stools and iron deficiency. For each patient, data regarding consultations by other gastroenterologists or surgeons working in the region, clinically relevant diagnoses and the number of gastrointestinal-related x-rays performed were obtained.

RESULTS:

Of a total sample size of 230 patients, 110 (47.8%) were seen by another gastroenterologist or surgeon after decline. A significant diagnosis was made in 21 patients (9.1%), which had immediate clinical consequences in 29%. Forty per cent of patients underwent one or more gastointestinal-related x-rays before being declined, which increased to 55% after decline.

CONCLUSION:

Approximately 50% of declined patients were seen by other gastroenterologists or surgeons in the region. In 9.1% of these patients, a clinically important diagnosis was made, of which one-quarter had immediate medical consequences.     

Use and abuse of faecal occult blood tests in an acute hospital inpatient setting

Background/Aims: The role of the faecal occult blood test (FOBT) is untested. The aims of this study were to define the use of FOBT in a general hospital setting and to determine its influence on patient management. Methods: Case notes and laboratory reports were retrospectively reviewed in all FOBTs performed in 2006 across three acute hospitals, with specific reference to clinical setting, indication, influence over clinical decision‐making and management. Both guaiac and immunological tests were performed on all specimens. Results: A total of 330 patients aged 2–104 (mean 74) years, 47% men, had 461 tests performed. A positive result was recorded in one or both tests in 64% of patients. Evidence of dietary restriction was found in only eight (2%) of patients and 218 (66%) patients took one or more medications that could have caused a false positive result. Indications were mostly for overt or suspected gastrointestinal blood loss with or without anaemia and/or iron deficiency, but 5% were for non‐bloody diarrhoea and 3% screening for colorectal cancer. Patient care was adversely affected or delayed in 54 patients (16%), mostly because of the result being the stimulus for the decision to refer or not for endoscopy. Only one was considered appropriate as a screening test for colorectal cancer. Conclusions: The FOBT was applied in clinically inappropriate settings without consideration to confounding issues, and often led to inappropriate clinical decisions with considerable cost to hospital and patient. There is no place for FOBT in an acute hospital setting.     

Colon cancer screening: which non-invasive filter tests?

The following non-invasive stool tests for colorectal cancer (CRC) screening exist: guaiac or immunochemical fecal occult blood testing (FOBT), genetic stool tests and the M2-PK. Currently the most widely used tests are guaiac-based (gFOBT). Several randomized controlled trials have shown that gFOBT are able to achieve a reduction in CRC-related mortality. This reduction is achieved by detecting asymptomatic cancers at an early stage with a better prognosis. However, gFOBT have a low sensitivity for colorectal adenomas and are thus unlikely to be able to reduce the incidence of CRC. Furthermore, gFOBT are not specific for human blood and can be influenced by external factors. Immunochemical tests (iFOBT) only detect human blood in the stool. In two recent randomized studies from the Netherlands comparing guaiac and immunochemical tests in the asymptomatic population, iFOBT were found to detect more cancers than gFOBT. Furthermore, iFOBT were able to detect more advanced adenomas thus having the potential to be able to reduce the incidence of CRC as well as CRC-related mortality. In the recently released European CRC screening guidelines, iFOBT are considered the screening test of choice. Several questions remain however. It is currently unknown what the optimal cut-off value for an iFOBT to be considered positive should be and what the number of stool samples is that are required. Genetic stool tests detect mutations in stool that can be found in CRC. The original test testing for 21 genetic changes was found to be superior to gFOBT for the detection of cancers. However, the sensitivity was moderate (51.6%) and the sensitivity for advanced adenomas was low. In the meantime the test has been modified improving DNA extraction and reducing the number of mutations tested for as well as including a methylation marker. The efficacy of the modified test in the screening population is unknown. M2-PK is an isomer of the enzyme pyruvate kinase that is involved in glycolysis. Studies have found a good sensitivity for cancers, a low sensitivity for advanced adenomas with a specificity of around 80%. Further studies in the screening population are required.     

Does Use of the Coloscreen Self-Test Improve Patient Compliance with Fecal Occult Blood Screening?

Occult blood-screening methods which do not require stool manipulation have been devised in an attempt to improve patient compliance with fecal occult blood testing. We performed a randomized, prospective study comparing patient compliance with the Coloscreen Self Test, a fecal occult blood detection method which does not require stool manipulation, and standard guaiac-impregnated cards in a VA clinic and a university-based private practice to determine whether the Coloscreen Self-Test would improve patient compliance with fecal occult blood testing. Overall, there was no significant difference in compliance between the two tests, with a compliance of 71% (105/147) for the guaiac cards and 60% (88/136) for the Coloscreen Self-Test ( p = 0.49). However, multiplte logistic regression showed that, when using the Coloscreen Self-Test, patients at the VA clinic had significantly reduced compliance. Only 46% (23/50) returned the Coloscreen Self-Test compared with 84% (42/50) who returned the guaiac cards ( p < 0.05). We conclude that the Coloscreen Self-Test does not improve patient compliance with fecal occult blood testing, and may reduce compliance in some sectors of the population.     

The cost-effectiveness of diagnostic testing strategies for Helicobacter pylori

OBJECTIVE: Several noninvasive methods are now available for diagnosing Helicobacter pylori infection. Because the prevalence of H. pylori infection is variable in patients requiring testing, the optimal testing strategies may vary under different conditions. The aim of this study was to evaluate the cost-effectiveness of competing diagnostic strategies for H. pylori in patients with varying H. pylori prevalence. METHODS: A decision analysis was performed comparing the costs per number of correct diagnoses achieved by alternative sequential testing strategies. Estimates of H. pylori prevalence and test characteristics were derived from a systematic review of the MEDLINE bibliographic database. Cost estimates were derived from the 2000 Medicare Fee Schedule. RESULTS: The enzyme-linked immunosorbent assay (ELISA) test had the lowest cost per correct diagnosis at low (30%), intermediate (60%), and high (90%) prevalence ($90-$95/correct diagnosis), but its diagnostic accuracy was low (80-84%). At low and intermediate prevalence the stool test was more accurate (93%), with an average cost of $126-$127 per correct diagnosis. Additional confirmatory testing of positive or negative tests increased the diagnostic accuracy of the stool test, but had high incremental costs. ELISA testing was preferable when prevalence rates were very high (90%), and using a confirmatory urea breath test for negative ELISA tests increased the diagnostic accuracy to 96%, with modest incremental costs. If the cost of the breath test was <$50 or if the cost of the stool test is >$82, breath testing became preferable to stool testing. If the cost of the stool test fell to <$20, it became preferable to ELISA. Similarly, if the cost of the ELISA serology was >$39 then stool testing became preferable at all prevalence rates. Fingerstick whole blood tests were not cost-effective. CONCLUSIONS: The choice of an initial test for H. pylori detection depends on the prevalence of H. pylori infection and the value placed on increased diagnostic accuracy. Although ELISA results in the lowest cost-effectiveness ratios, in patients at low-intermediate pretest probability of infection, the stool test provides increased accuracy, with modest incremental costs.     

Early detection and control of cancer in clinical practice

As part of the Community Cancer Care Evaluation, a random-sample survey of practicing physicians in 12 geographic areas was conducted in 1985 to provide information about physician practice patterns with reference to cancer detection, control, and treatment. All respondents were asked whether they routinely performed comprehensive physical examinations, breast palpations, mammography, rectal examinations, chest roentgenography, and stool guaiac examinations on normal healthy patients older than 50 years. Responses were examined in terms of American Cancer Society and National Cancer Institute (Bethesda, Md) recommendations. Conformity with recommendations was dependent on the geographic area, the specific procedure, and the specialty of the physician. Across all procedures, frequency of performance varied with years since graduation from medical school, with more recent graduates more likely to conform to recommended standards.     

Yield of the screening review of systems

STUDY OBJECTIVE: To determine the usefulness of screening reviews of the cardiopulmonary and gastrointestinal systems during medical admissions. DESIGN: Case series. SETTING: General internal medicine ward of a university hospital. PATIENTS: 550 consecutive medical patients were initially screened at admission. The authors excluded 265 patients with life-limiting medical conditions, and they studied 98 patients with no known cardiopulmonary disease and 207 patients with no known gastrointestinal disease. INTERVENTIONS: Positive responses to screening systems review questions were evaluated using a standardized testing algorithm. MAIN OUTCOME MEASURES: Numbers of new diagnoses; potential for patient benefit. MAIN RESULTS: The authors made 26 new diagnoses for 25 patients (95% confidence limits, 16 to 37 patients), two of whom may have gained years of life as a result. CONCLUSIONS: The absolute yield of the screening cardiopulmonary and gastrointestinal reviews of systems of 550 patients admitted to an internal medicine service of a university hospital was a new diagnosis in about 5% of patients. An estimate of the cost-effectiveness compares favorably with those of other accepted screening practices.     

Performance Characteristics and Comparison of Two Immunochemical and Two Guaiac Fecal Occult Blood Screening Tests for Colorectal Neoplasia

A new immunochemical test for stool Hb, FlexSureOBT, was compared with the immunochemical HemeSelect andguaiac Hemoccult II and Hemoccult SENSA tests. Blindeddevelopment of test cards smeared with stools having added human blood showed betteranalytical sensitivity of FlexSure OBT (0.2 ml blood/100g feces), than Hemoccult SENSA (0.5 ml) or HemoccultII (1.0 ml). All four stool tests were prepared by 403 subjects having endoscopic examinations.The guaiac tests and FlexSure OBT were easy to prepareand develop. The positivity rate of Hemoccult SENSA was8.7%, Hemoccult II 6%, FlexSure OBT 4.2%, and HemeSelect 3.4%. In this mainly asymptomatic(97%) population, 98% were free of clinicallysignificant neoplasia (five had cancers, three hadadenomas 1.0 cm). Sensitivity for cancers oradenomas 1.0 cm was similar for all tests (62.5-86%, NS) andHemoccult SENSA had the lowest specificity (92% vs95-98%, P < 0.05); but both Hemoccult II andHemoccult SENSA had significantly lower predictivepositive values (21% and 14%) than either FlexSure OBT(29%) or HemeSelect (50%) (P < 0.05). If bothHemoccult SENSA and FlexSURE OBT were positive in thesame subjects (1.7%), sensitivity for cancer or adenomas 1.0 cm (50%) was not significantly betterthan guaiac tests, but specificity (99.2%) andpredictive positive (57%) values were improved (P <0.05). In this population, guaiac tests were assensitive as immunochemical tests for clinically significantcolorectal neoplasia, but with significantly lowerpredictive positive values. A combination of a sensitiveguaiac test (Hemoccult SENSA) and a specificconfirmatory test for human Hb (FlexSure OBT) provided highspecificity, comparable to HemeSelect.