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Paul Rozen - One of the best experts on this subject based on the ideXlab platform.
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a quantitative immunochemical faecal occult blood test is more efficient for detecting significant colorectal neoplasia than a sensitive Guaiac test
Alimentary Pharmacology & Therapeutics, 2006Co-Authors: Zohar Levi, Rachel Hazazi, Paul Rozen, Alexander Vilkin, Amal Waked, Yaron NivAbstract:Summary Background The sensitive Guaiac faecal occult blood test, Haemoccult SENSA (HOS; Beckman Coulter, Fullerton, CA, USA), is our standard screening test for significant colorectal neoplasia. We evaluated an automatically-developed, quantified human haemoglobin immunochemical faecal test, OC-MICRO (Eiken Chemical Co., Tokyo, Japan), to improve test specificity and so reduce the colonoscopy burden. Aim To compare Guaiac faecal occult blood test and immunochemical faecal test diagnostic efficacy and costs for identifying significant neoplasia. Methods Colonoscopies were performed on patients who prepared three daily Guaiac faecal occult blood tests with or without immunochemical faecal tests. Results Total colonoscopy was performed on 151 subjects who prepared both Guaiac and immunochemical faecal tests (group 1) and the positive predictive values (PPV) were also compared to those of 162 subjects undergoing colonoscopy for positive Guaiac faecal occult blood tests (group 2). In group 1, comparative sensitivity, specificity, and PPVs for significant neoplasia with Guaiac faecal occult blood test were 75%, 34%, and 12% (PPV, 18% for group 2) and with immunochemical faecal test were 75%, 94% and 60% (P < 0.01 for specificity). The number of colonoscopy examinations needed to detect a significant neoplasm because of positive faecal occult blood tests was six to eight with HOS and two with OC-MICRO at 21–31% the cost of evaluating a positive Guaiac faecal occult blood test. Conclusion An immunochemical faecal test maintains the high sensitivity of Guaiac faecal occult blood test, but significantly reduces the colonoscopy burden and screening costs.
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a sensitive Guaiac faecal occult blood test is less useful than an immunochemical test for colorectal cancer screening in a chinese population
Alimentary Pharmacology & Therapeutics, 2003Co-Authors: B C Y Wong, Paul Rozen, W M Wong, K L Cheung, Teresa Tong, Graeme P Young, K W Chu, W L Law, H M Tung, K C LaiAbstract:Summary 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 ≥ 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.
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choice of fecal occult blood tests for colorectal cancer screening recommendations based on performance characteristics in population studies a who world health organization and omed world organization for digestive endoscopy report
The American Journal of Gastroenterology, 2002Co-Authors: Graeme P Young, James D B St John, Sidney J Winawer, Paul RozenAbstract:OBJECTIVE: There is now strong evidence that screening for colorectal cancer with fecal occult blood tests (FOBTs) is effective in reducing the incidence and mortality of this disease. Various FOBTs are now available with a wide range of evidence supporting their use. The purpose of this study was to review published data on the performance of these FOBTs to provide recommendations for their effective use in screening. METHODS: A joint committee representing the World Health Organization and the World Organization for Digestive Endoscopy was established for this study. A process was designed that would search the literature systematically for evidence of FOBT performance. Criteria for including studies in this paper were established based on study design, cohort size, and performance variables reported. RESULTS: Of the Guaiac tests, Hemoccult SENSA had the highest sensitivity for cancer and adenomas but a high test positivity. It had a better readability than the older Hemoccult II test. Immunochemical tests, HemeSelect, FlexSure OBT, and Immudia Hem Sp have acceptable performance characteristics and are easier for participants to use but are more expensive. These tests have been well studied in large cohorts, but only Immudia Hem Sp is commercially available. CONCLUSIONS: At present, there is no extensively studied FOBT that fulfills the needs for all target populations worldwide. Choice of FOBT should take into account population dietary compliance and colonoscopy resources: The more sensitive newer tests should be used if dietary compliance is good (in the case of Guaiac tests) and colonoscopy resources are adequate for diagnostic workup of people who test positive. Immunochemical tests remove the difficulties created by diet and drug restrictions and are more amenable to standardized development and quality control.
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comparative screening with a sensitive Guaiac and specific immunochemical occult blood test in an endoscopic study
Cancer, 2000Co-Authors: Paul Rozen, Judith Knaani, Ziona SamuelAbstract:BACKGROUND HemoccultSENSA (HOS), the sensitive Guaiac fecal occult blood test (FOBT) for colorectal neoplasia, is faulted for its low specificity, which might be improved by substituting or adding FlexSure OBT (FS), the immunochemical test for human hemoglobin. (Both tests are manufactured by Beckman-Coulter Inc., Primary Care Diagnostics, Palo Alto, CA.) The authors compared both FOBTs in an endoscopic study to determine which FOBT to recommend for a population-screening program. METHODS Both FOBTs, without dietary restrictions, were prepared by 1410 screenees or nonbleeding symptomatic patients (3%). All underwent colonoscopy (51.8%) or flexible sigmoidoscopy (if asymptomatic and both FOBTs were negative). RESULTS HOS sensitivity for significant neoplasia, cancers, or adenomas ≥ 1 cm (20 cases) was similar to that of FS (50% vs. 35%, not significant). However, HOS specificity was lower (95% vs. 99%, confidence interval (CIs) 94–96 vs. 98–99, P < 0.05). In those 11 cases in which both HOS and FS were positive, specificity for significant neoplasia was 100% but sensitivity decreased to 25% (less than HOS alone, P < 0.05). HOS was more sensitive than FS for any neoplasia (55 cases), including adenomas < 1 cm (35% vs. 18%, CIs 22–47 vs. 8–28, P < 0.05), but less specific (96% vs. 99%, CIs 95–97 vs. 98–100, P < 0.05). CONCLUSIONS Guaiac HOS, which does not require dietary restrictions, is significantly more sensitive for any colorectal neoplasm than the immunochemical FS; it identifies more adenomas with a specificity that is low but acceptable for population screening. Cancer 2000;89:46–52. © 2000 American Cancer Society.
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performance characteristics and comparison of two immunochemical and two Guaiac fecal occult blood screening tests for colorectal neoplasia
Digestive Diseases and Sciences, 1997Co-Authors: Paul Rozen, Judith Knaani, Ziona SamuelAbstract:A new immunochemical test for stool Hb, FlexSure OBT, was compared with the immunochemical HemeSelect and Guaiac Hemoccult II and Hemoccult SENSA tests. Blinded development of test cards smeared with stools having added human blood showed better analytical sensitivity of FlexSure OBT (0.2 ml blood/100 g feces), than Hemoccult SENSA (> or =0.5 ml) or Hemoccult II (> or =1.0 ml). All four stool tests were prepared by 403 subjects having endoscopic examinations. The Guaiac tests and FlexSure OBT were easy to prepare and develop. The positivity rate of Hemoccult SENSA was 8.7%, Hemoccult II 6%, FlexSure OBT 4.2%, and HemeSelect 3.4%. In this mainly asymptomatic (97%) population, 98% were free of clinically significant neoplasia (five had cancers, three had adenomas > or =1.0 cm). Sensitivity for cancers or adenomas > or =1.0 cm was similar for all tests (62.5-86%, NS) and Hemoccult SENSA had the lowest specificity (92% vs 95-98%, P or =1.0 cm (50%) was not significantly better than Guaiac tests, but specificity (99.2%) and predictive positive (57%) values were improved (P < 0.05). In this population, Guaiac tests were as sensitive as immunochemical tests for clinically significant colorectal neoplasia, but with significantly lower predictive positive values. A combination of a sensitive Guaiac test (Hemoccult SENSA) and a specific confirmatory test for human Hb (FlexSure OBT) provided high specificity, comparable to HemeSelect.
S Ciatto - One of the best experts on this subject based on the ideXlab platform.
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measuring interval cancers in population based screening using different assays of fecal occult blood testing the district of florence experience
International Journal of Cancer, 2001Co-Authors: Marco Zappa, Guido Castiglione, Eugenio Paci, Grazia Grazzini, Tiziana Rubeca, Patricia Turco, Emanuele Crocetti, S CiattoAbstract:The fecal occult blood test (FOBT) has demonstrated its efficacy in reducing mortality from colorectal cancer (CRC). The Guaiac-based FOBT has been criticized for its low sensitivity. In this study, two different assays for FOBT (Guaiac or an immunochemical test based on reversed passive hemagglutination [RPHA]) were tested for comparison within a population-based screening program for colorectal cancer in the province of Florence (Italy). The proportional incidence method was used to calculate sensitivity for both FOBTs, according to rank of screening (first or repeat), age at entry (two groups of 50 to 59 and 60 to 70 years old) and lesion site (colon or rectum). When comparing FOBTs, the sensitivity multivariate Poisson regression was used to adjust for other variables. The sensitivity after the first 2 years was 50% (95% confidence interval [CI] 34% to 63%) for the Guaiac test versus 82% (95% CI 67% to 92%) for RPHA. At multivariate analysis the risk of developing an interval cancer after a Guaiac test is almost 3 times that after RPHA (rate ratio = 2.64; 95% CI 1.3 to 5.4). Our study confirms that RPHA is more sensitive than the Guaiac test. The assumption that FOBT screening for CRC has to be based on a Guaiac test should be reconsidered, and RPHA should be recommended as the standard FOBT for screening purposes.
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immunochemical vs Guaiac faecal occult blood tests in a population based screening programme for colorectal cancer
British Journal of Cancer, 1996Co-Authors: Guido Castiglione, Grazia Grazzini, M Zappa, Antonia Mazzotta, M Biagini, P Salvadori, S CiattoAbstract:Two faecal occult blood tests (FOBTs), Hemoccult II (Guaiac based) and Hemeselect (immunochemical) were compared in a population screening for colorectal cancer on 24 282 subjects aged 40-70. Hemeselect was interpreted according to a lower (+ and +/-) and a higher (+) positivity threshold. A total of 8008 compliers were enrolled in the study. Positivity rates: Hemoccult = 6.0%, Hemeselect (+ and +/) = 8.2%, Hemeselect (+) = 3.1%. Among FOBT-positive subject complying with the diagnostic work-up, 22 had colorectal cancer (17 Hemeselect-positive (+), four Hemeselect-borderline (+/-), 15 Hemoccult-positive) and 166 subjects had adenomas (62 Hemeselect(+), 56 Hemeselect-borderline (+/-), 79 Hemoccult-positive) were detected. The positive predictive values (PPVs) for cancer were as follows: Hemoccult = 3.7%, Hemeselect (+ and +/-) = 3.8%, Hemeselect (+) = 8.4%. The PPVs for adenoma(s) were: Hemoccult = 19.7%, Hemeselect (+ and +/-) = 21.4%, Hemeselect (+) = 30.5%. The specificity for cancer was: Hemoccult = 94.1%, Hemeselect (+ +/-) = 92%, Hemeselect (+) = 97.1%. Ratios between detection rates of each test and expected incidence of colorectal cancer suggest that Hemoccult anticipates cancer diagnosis by approximately 2 years on average whereas the mean diagnostic anticipation of Hemeselect ranges between 2.5 and 3.2 years. Hemeselect is superior to Hemoccult as it is at least as effective but more efficient and acceptable than Guaiac testing. Further evaluation of Hemeselect cost-effectiveness and sensitivity is needed in order to assess the optimal threshold of positivity and screening frequency.
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Guaiac and immunochemical tests for faecal occult blood in colorectal cancer screening
British Journal of Cancer, 1992Co-Authors: Guido Castiglione, Grazia Grazzini, S CiattoAbstract:Seven hundred and eighty-six subjects spontaneously referring to our Center performed two Guaiac (Rehydrated Hemoccult II (R.HO), and Hemoccult Sensa (HO S.)), and two immunochemical (OC Hemodia (Hdia) and Hemeselect (Hsel)) faecal occult blood tests on three consecutive faecal determinations. The positivity rates of 3 day R.HO, HO S., Hdia, and Hsel were 4.8%, 5.6%, 8.4% and 11.2% respectively. One hundred and thirty-five of the 150 subjects with at least one positive test completed the diagnostic work-up. Cancer was detected in three subjects and adenomas in 15. Three-day specificity estimates of R.HO, HO S., Hdia and Hsel in the overall series were 96.1%, 96.0%, 93.8% and 91.2% respectively, the differences between Guaiac and immunochemical tests being significant. Corresponding values of specificity as determined on the first faecal sample only in the overall series were 98.1%, 98.3%, 96.1% and 94.9% respectively. No significant difference in specificity is evident when 3-day Guaiac tests are compared to 1-day immunochemical ones. Three-day immunochemical testing is not recommended for screening purposes due to its very low specificity. Nevertheless, 1-day immunochemical testing is almost as specific as 3-day Guaiac testing. A preliminary estimate of colonic neoplasms detection rates shows no difference as well. The benefit of 1-day testing on screening acceptability is evident, but the impact on sensitivity should be evaluated in a screening situation with a proper study design and a larger sample size.
Hermann Brenner - One of the best experts on this subject based on the ideXlab platform.
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diagnostic performance of Guaiac based fecal occult blood test in routine screening state wide analysis from bavaria germany
The American Journal of Gastroenterology, 2014Co-Authors: Hermann Brenner, Michael Hoffmeister, Berndt Birkner, Christian StockAbstract:Diagnostic Performance of Guaiac-Based Fecal Occult Blood Test in Routine Screening: State-Wide Analysis from Bavaria, Germany
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sex differences in performance of fecal occult blood testing
The American Journal of Gastroenterology, 2010Co-Authors: Hermann Brenner, Ulrike Haug, Sabrina HundtAbstract:OBJECTIVES:Immunological and Guaiac-based fecal occult blood tests (iFOBTs and gFOBTs) are widely used for early detection of colorectal cancer (CRC). We aimed to assess potential sex differences in performance of iFOBTs and gFOBT in the screening setting.METHODS:The sensitivity, specificity, and po
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comparative evaluation of immunochemical fecal occult blood tests for colorectal adenoma detection
Annals of Internal Medicine, 2009Co-Authors: Sabrina Hundt, Ulrike Haug, Hermann BrennerAbstract:The various immunochemical fecal occult blood tests (iFOBTs) use different antibodies against human blood components. The authors compared characteristics of 6 qualitative iFOBTs and 1 Guaiac-based...
Guido Castiglione - One of the best experts on this subject based on the ideXlab platform.
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measuring interval cancers in population based screening using different assays of fecal occult blood testing the district of florence experience
International Journal of Cancer, 2001Co-Authors: Marco Zappa, Guido Castiglione, Eugenio Paci, Grazia Grazzini, Tiziana Rubeca, Patricia Turco, Emanuele Crocetti, S CiattoAbstract:The fecal occult blood test (FOBT) has demonstrated its efficacy in reducing mortality from colorectal cancer (CRC). The Guaiac-based FOBT has been criticized for its low sensitivity. In this study, two different assays for FOBT (Guaiac or an immunochemical test based on reversed passive hemagglutination [RPHA]) were tested for comparison within a population-based screening program for colorectal cancer in the province of Florence (Italy). The proportional incidence method was used to calculate sensitivity for both FOBTs, according to rank of screening (first or repeat), age at entry (two groups of 50 to 59 and 60 to 70 years old) and lesion site (colon or rectum). When comparing FOBTs, the sensitivity multivariate Poisson regression was used to adjust for other variables. The sensitivity after the first 2 years was 50% (95% confidence interval [CI] 34% to 63%) for the Guaiac test versus 82% (95% CI 67% to 92%) for RPHA. At multivariate analysis the risk of developing an interval cancer after a Guaiac test is almost 3 times that after RPHA (rate ratio = 2.64; 95% CI 1.3 to 5.4). Our study confirms that RPHA is more sensitive than the Guaiac test. The assumption that FOBT screening for CRC has to be based on a Guaiac test should be reconsidered, and RPHA should be recommended as the standard FOBT for screening purposes.
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immunochemical vs Guaiac faecal occult blood tests in a population based screening programme for colorectal cancer
British Journal of Cancer, 1996Co-Authors: Guido Castiglione, Grazia Grazzini, M Zappa, Antonia Mazzotta, M Biagini, P Salvadori, S CiattoAbstract:Two faecal occult blood tests (FOBTs), Hemoccult II (Guaiac based) and Hemeselect (immunochemical) were compared in a population screening for colorectal cancer on 24 282 subjects aged 40-70. Hemeselect was interpreted according to a lower (+ and +/-) and a higher (+) positivity threshold. A total of 8008 compliers were enrolled in the study. Positivity rates: Hemoccult = 6.0%, Hemeselect (+ and +/) = 8.2%, Hemeselect (+) = 3.1%. Among FOBT-positive subject complying with the diagnostic work-up, 22 had colorectal cancer (17 Hemeselect-positive (+), four Hemeselect-borderline (+/-), 15 Hemoccult-positive) and 166 subjects had adenomas (62 Hemeselect(+), 56 Hemeselect-borderline (+/-), 79 Hemoccult-positive) were detected. The positive predictive values (PPVs) for cancer were as follows: Hemoccult = 3.7%, Hemeselect (+ and +/-) = 3.8%, Hemeselect (+) = 8.4%. The PPVs for adenoma(s) were: Hemoccult = 19.7%, Hemeselect (+ and +/-) = 21.4%, Hemeselect (+) = 30.5%. The specificity for cancer was: Hemoccult = 94.1%, Hemeselect (+ +/-) = 92%, Hemeselect (+) = 97.1%. Ratios between detection rates of each test and expected incidence of colorectal cancer suggest that Hemoccult anticipates cancer diagnosis by approximately 2 years on average whereas the mean diagnostic anticipation of Hemeselect ranges between 2.5 and 3.2 years. Hemeselect is superior to Hemoccult as it is at least as effective but more efficient and acceptable than Guaiac testing. Further evaluation of Hemeselect cost-effectiveness and sensitivity is needed in order to assess the optimal threshold of positivity and screening frequency.
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Guaiac and immunochemical tests for faecal occult blood in colorectal cancer screening
British Journal of Cancer, 1992Co-Authors: Guido Castiglione, Grazia Grazzini, S CiattoAbstract:Seven hundred and eighty-six subjects spontaneously referring to our Center performed two Guaiac (Rehydrated Hemoccult II (R.HO), and Hemoccult Sensa (HO S.)), and two immunochemical (OC Hemodia (Hdia) and Hemeselect (Hsel)) faecal occult blood tests on three consecutive faecal determinations. The positivity rates of 3 day R.HO, HO S., Hdia, and Hsel were 4.8%, 5.6%, 8.4% and 11.2% respectively. One hundred and thirty-five of the 150 subjects with at least one positive test completed the diagnostic work-up. Cancer was detected in three subjects and adenomas in 15. Three-day specificity estimates of R.HO, HO S., Hdia and Hsel in the overall series were 96.1%, 96.0%, 93.8% and 91.2% respectively, the differences between Guaiac and immunochemical tests being significant. Corresponding values of specificity as determined on the first faecal sample only in the overall series were 98.1%, 98.3%, 96.1% and 94.9% respectively. No significant difference in specificity is evident when 3-day Guaiac tests are compared to 1-day immunochemical ones. Three-day immunochemical testing is not recommended for screening purposes due to its very low specificity. Nevertheless, 1-day immunochemical testing is almost as specific as 3-day Guaiac testing. A preliminary estimate of colonic neoplasms detection rates shows no difference as well. The benefit of 1-day testing on screening acceptability is evident, but the impact on sensitivity should be evaluated in a screening situation with a proper study design and a larger sample size.
James E Allison - One of the best experts on this subject based on the ideXlab platform.
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faecal immunochemical tests versus Guaiac faecal occult blood tests what clinicians and colorectal cancer screening programme organisers need to know
Gut, 2015Co-Authors: Jill Tinmouth, Iris Lansdorpvogelaar, James E AllisonAbstract:Although colorectal cancer (CRC) is a common cause of cancer-related death, it is fortunately amenable to screening with faecal tests for occult blood and endoscopic tests. Despite the evidence for the efficacy of Guaiac-based faecal occult blood tests (gFOBT), they have not been popular with primary care providers in many jurisdictions, in part because of poor sensitivity for advanced colorectal neoplasms (advanced adenomas and CRC). In order to address this issue, high sensitivity gFOBT have been recommended, however, these tests are limited by a reduction in specificity compared with the traditional gFOBT. Where colonoscopy is available, some providers have opted to recommend screening colonoscopy to their patients instead of faecal testing, as they believe it to be a better test. Newer methods for detecting occult human blood in faeces have been developed. These tests, called faecal immunochemical tests (FIT), are immunoassays specific for human haemoglobin. FIT hold considerable promise over the traditional Guaiac methods including improved analytical and clinical sensitivity for CRC, better detection of advanced adenomas, and greater screenee participation. In addition, the quantitative FIT are more flexible than gFOBT as a numerical result is reported, allowing customisation of the positivity threshold. When compared with endoscopy, FIT are less sensitive for the detection of advanced colorectal neoplasms when only one time testing is applied to a screening population; however, this is offset by improved participation in a programme of annual or biennial screens and a better safety profile. This review will describe how gFOBT and FIT work and will present the evidence that supports the use of FIT over gFOBT, including the cost-effectiveness of FIT relative to gFOBT. Finally, specific issues related to FIT implementation will be discussed, particularly with respect to organised CRC screening programmes.
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a comparison of fecal occult blood tests for colorectal cancer screening
The New England Journal of Medicine, 1996Co-Authors: James E Allison, Irene S Tekawa, Laura J Ransom, Alyn L AdrainAbstract:Background Hemoccult II, a widely used Guaiac test for fecal occult blood, has a low sensitivity for detecting colorectal neoplasms in asymptomatic patients at average risk. In such patients, the performance characteristics of screening tests developed to improve on Hemoccult II are not known. Methods A set of three fecal occult-blood tests — Hemoccult II; Hemoccult II Sensa, a more sensitive Guaiac test; and HemeSelect, an immunochemical test for human hemoglobin — was mailed to all patients 50 years of age or older who were scheduled for personal health appraisals at the Kaiser Permanente Medical Center in Oakland, California. The performance of each test and of a combination test (HemeSelect to confirm positive Hemoccult II Sensa results) was evaluated by identifying screened patients who had colorectal neoplasms (carcinoma or a polyp >1 cm in diameter) in the two years after screening. Results Of the 10,702 eligible patients, 8104 (75.7 percent) had at least one interpretable sample and were screened ...
