Basic variables at different positivity thresholds of a quantitative immunochemical test for faecal occult blood

2002 ◽  
Vol 9 (3) ◽  
pp. 99-103 ◽  
Author(s):  
G. Castiglione ◽  
G. Grazzini ◽  
G. Miccinesi ◽  
T. Rubeca ◽  
C. Sani ◽  
...  
Keyword(s):  
High Risk ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Occult Blood ◽  
Recall Rate ◽  
Population Based ◽  
Detection Rates ◽  
Predictive Values ◽  
Faecal Occult Blood ◽  
Faecal Occult

OBJECTIVES: Screening by faecal occult blood testing (FOBT) is effective in decreasing mortality and incidence of colorectal cancer (CRC). Immunochemical tests have proved to be more cost effective than guaiac FOBTs. The latex agglutination test (LAT) has the advantage of being a fully automated, quantitative test. The aim of this study is to interpret the overall experience with LAT according to different positivity thresholds. SETTING: A population based screening programme is currently running involving subjects aged 50–70, invited every 2 years to have an FOBT. LAT is the standard screening test and has a positivity threshold for further diagnostic tests of 100 ng haemoglobin/ml of sample solution. METHODS: Positivity rates, detection rates for CRC high risk adenomas, and positive predictive values for CRC, high risk adenomas, and low risk adenomas were calculated for several positivity thresholds. RESULTS: 19 132 attendances at screening were recorded (11 774 at first screening, 7358 at subsequent screenings). Progressively increasing the positivity threshold from 100 to 200 ng/ml showed (a) a decrease in positivity rate; (b) a decrease in detection rates for CRC or high risk adenomas; (c) an increase in positive predictive values for cancer; (d) an increase in positive predictive value for high risk adenomas. CONCLUSIONS: Increasing the positivity threshold of the LAT reduces recall rate and improves positive predictive value for cancer or high risk adenomas but substantially decreases the detection rate of CRC and high risk adenomas. For this reason increasing the positivity cut off for LATs is not advisable. On the other hand decreasing the positivity threshold would increase recall rate and sensitivity of screening. Careful evaluation of sensitivity of the quantitative results of the LAT for interval cancers is needed to definitively assess the optimal positivity threshold for LATs in population based screening programmes.

scholarly journals Cost Analysis in a Population Based Screening Programme for Colorectal Cancer: Comparison of Immunochemical and Guaiac Faecal Occult Blood Testing

1997 ◽  
Vol 4 (3) ◽  
pp. 142-146 ◽  
Author(s):  
G Castiglione ◽  
M Zappa ◽  
G Grazzini ◽  
C Sani ◽  
A Mazzotta ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Screening Programme ◽  
Cost Effective ◽  
Occult Blood ◽  
Recall Rate ◽  
Population Based ◽  
Faecal Occult Blood Testing ◽  
Faecal Occult Blood ◽  
Blood Tests ◽  
Faecal Occult

Objective— To compare the costs of colorectal cancer (CRC) screening by two faecal occult blood tests (FOBT)—namely, Hemoccult (guaiac based) and reversed passive haemagglutination (RPHA) tests. RPHA was interpreted according to two positivity thresholds (+ or +/-). Methods— Attenders performed both tests. Subjects with a positive FOBT test were invited to have a complete exploration of the colon. The total costs for every 10 000 screened subjects and costs for each unit of result (screened subject, or patient with adenoma/s or cancer detected) were calculated for both tests. Results— 8353 subjects were enrolled. A total of 2109 repeated screening after two years. RPHA(+ and +/-) showed the highest and RPHA(+) the lowest positivity rate at first screening. The Hemoccult positivity rate was highest at repeat screening. Total costs of screening by RPHA(+ and +/-) were highest as this method had the highest recall rate. Screening by RPHA(+) was the least costly. Costs for each screened subject were highest for RPHA(+ and +/-) and lowest for RPHA(+). Costs for each cancer detected were lowest for RPHA(+) and highest for Hemoccult or RPHA(+ and +/-) in subjects aged > 49 or < 50, respectively. Costs for subjects with detected adenoma/s of > 9 mm were lowest for RPHA(+ and +/-) and highest for Hemoccult. At repeat screening total costs of RPHA(+ and +/-) were lower than at first screening, whereas for each subject with cancer or adenoma/s costs were increased. Conclusions— Our data confirm that screening by RPHA is more cost effective than by Hemoccult.

Screening for colorectal cancer by faecal occult blood test: comparison of immunochemical tests

2000 ◽  
Vol 7 (1) ◽  
pp. 35-37 ◽  
Author(s):  
G. Castiglione ◽  
M. Zappa ◽  
G. Grazzini ◽  
T. Rubeca ◽  
P. Turco ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
High Risk ◽  
Occult Blood ◽  
Faecal Occult Blood Test ◽  
Population Based ◽  
Latex Agglutination ◽  
Faecal Occult Blood ◽  
Faecal Occult ◽  
Diagnostic Work ◽  
Work Up

Objective To compare two immunochemical faecal occult blood tests based on reversed passive haemagglutination (RPHA) or latex agglutination (Hdia) in a population based screening setting. Method Hdia was interpreted according to three positivity thresholds: 100, 150, or 200 ng of haemoglobin/mg of specimen solution. A total of 5844 subjects were recruited into the study, from 17 432 invited subjects aged 50–70. Results Positivity rates were 3.3% for RPHA, Hdia100 3.5%, Hdia150 2.5%, Hdia200 2.0%. Among subjects complying with the diagnostic work up, colorectal cancer (CRC) was detected in 19 subjects (17 RPHA positive, 16 Hdia100 positive, 15 Hdia150 positive, 14 Hdia200 positive) and high risk adenoma/s in 41 subjects (28 RPHA positive, 32 Hdia100 positive, 29 Hdia150 positive, 25 Hdia200 positive). The prevalence of screen positive CRC in the population was for RPHA 2.9‰, Hdia100 2.7‰, Hdia150 2.6‰, Hdia200 2.4‰. The prevalence of screen positive high risk adenomas in the population was for RPHA 4.8‰, Hdia100 5.5‰, Hdia150 5.0‰, Hdia200 4.3‰. Conclusion Hdia100 was as sensitive as RPHA for cancer and high risk adenomas. As Hdia is less technically complex than RPHA, it is a valid alternative to the latter, provided that full automation of the development procedure is available. Increasing the positivity threshold of Hdia up to 150 or 200 ng of haemoglobin/mg of specimen solution is not advisable as the increase in specificity is too small to justify the corresponding decrease in the detection of screen positive cancers in the population.

Detection Rate, Recall Rate, and Positive Predictive Value of Digital Compared to Screen-Film Mammography in the Quebec Population-Based Breast Cancer Screening Program

2016 ◽  
Vol 67 (4) ◽  
pp. 330-338 ◽  
Author(s):  
Isabelle Théberge ◽  
Nathalie Vandal ◽  
André Langlois ◽  
Éric Pelletier ◽  
Jacques Brisson
Keyword(s):  
Positive Predictive Value ◽  
Predictive Value ◽  
Detection Rate ◽  
Screening Program ◽  
Computed Radiography ◽  
Recall Rate ◽  
Population Based ◽  
Mixed Effect ◽  
Detection Rates ◽  
Institutional Review

Purpose The study sought to compare performance indicators of computed radiography (CR) using different plate readers, digital direct radiography (DR), and screen-film mammography (SFM) in a population-based screening program. Methods This analysis involved women 50-69 years of age who participated in the breast screening program of Quebec (Canada) and who had screening mammogram between January 1, 2007, and September 30, 2012. The detection rate, recall rate, and positive predictive value of CR (n = 672,125 mammograms) and DR (n = 60,023) were compared to SFM (n = 782,894) using mixed-effect logistic regression, adjusting for potential confounders. No institutional review board approval was required. Results CR was not associated with change in cancer detection rate (odds ratio [OR]: 0.95; 95% confidence interval [CI]: 0.88-1.03), but with a small increase in recall rate (OR: 1.03; 95% CI: 1.01-1.06) compared to SFM. The association of CR with recall rate varies with the CR plate reader manufacturer ( P < .0001). DR was not associated with change in detection rate (OR: 1.06; 95% CI: 0.89-1.25), but with an increase in the recall rate (OR: 1.25; 95% CI: 1.19-1.30) compared to SFM. Conclusions In our screening program, digital mammograms gave detection rates equivalent to those of SFM, but with an increase of recall rate, particularly for DR. If this situation persists, the adoption of DR may increase the adverse effects of screening with little or no benefit for women.

scholarly journals High test positivity and low positive predictive value for colorectal cancer of continued faecal occult blood test screening after negative colonoscopy

2017 ◽  
Vol 25 (2) ◽  
pp. 70-75 ◽  
Author(s):  
Jeremy P Brown ◽  
Kate Wooldrage ◽  
Suzanne Wright ◽  
Claire Nickerson ◽  
Amanda J Cross ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Positive Predictive Value ◽  
Predictive Value ◽  
Blood Test ◽  
Occult Blood ◽  
Faecal Occult Blood Test ◽  
Occult Blood Test ◽  
Diagnostic Investigation ◽  
Faecal Occult Blood ◽  
Faecal Occult

Objectives The English Bowel Cancer Screening Programme offers biennial guaiac faecal occult blood test (gFOBT) screening to 60–74-year-olds. Participants with positive results are referred for follow-up, but many do not have significant findings. If they remain age eligible, these individuals are reinvited for gFOBT screening. We evaluated the performance of repeat screening in this group. Methods We analysed data on programme participants reinvited to gFOBT screening after either previous negative gFOBT ( n = 327,542), or positive gFOBT followed by a diagnostic investigation negative for colorectal cancer (CRC) or adenomas requiring surveillance ( n = 42,280). Outcomes calculated were uptake, test positivity, yield of CRC, and positive predictive value (PPV) of gFOBT for CRC. Results For participants with a previous negative gFOBT, uptake in the subsequent screening round was 87.5%, positivity was 1.3%, yield of CRC was 0.112% of those adequately screened, and the PPV of gFOBT for CRC was 9.1%. After a positive gFOBT and a negative diagnostic investigation, uptake in the repeat screening round was 82.6%, positivity was 11.3%, CRC yield was 0.172% of participants adequately screened, and the PPV of gFOBT for CRC was 1.7%. Conclusion With high positivity and low PPV for CRC, the suitability of routine repeat gFOBT screening in two years among individuals with a previous positive test and a negative diagnostic examination needs to be carefully considered.

scholarly journals Changes in prevalence of faecal occult blood positivity over time

2019 ◽  
Vol 26 (4) ◽  
pp. 191-196 ◽  
Author(s):  
Anna Goulding ◽  
Gavin RC Clark ◽  
Annie S Anderson ◽  
Judith A Strachan ◽  
Callum G Fraser ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Positive Predictive Value ◽  
Blood Test ◽  
Screening Programme ◽  
Occult Blood ◽  
Faecal Occult Blood Test ◽  
Occult Blood Test ◽  
Faecal Occult Blood ◽  
Faecal Occult ◽  
Over Time

Objectives Changes in the prevalence of faecal occult blood test positivity over time have not been previously reported, but could have important implications. This study examined the positivity of the initial guaiac faecal occult blood test, a surrogate marker for colorectal bleeding, in participants aged 50 in a national bowel screening programme. Methods Data from the Scottish Bowel Screening Programme were used to study the initial positivity of the guaiac faecal occult blood test between 2007 and 2017. Positive predictive values of the testing process for colorectal cancer and adenoma were assessed over the same time period. Results Across Scotland, the initial guaiac faecal occult blood test positivity increased from 4.1 to 10.8%. In NHS Grampian and NHS Fife, two of the three NHS Boards which began roll-out of screening in 2007, it increased from 4.0 to 10.9%. In the Scottish Bowel Screening Programme, the positive predictive value declined from 11.0 to 6.6% for colorectal cancer and increased from 31.6 to 39.8% for adenoma. Conclusions In the Scottish programme over a decade, initial guaiac faecal occult blood test positivity increased in participants aged 50. This may be associated with changes in lifestyle and might have implications for screening clinical outcomes, including positive predictive value.

Faecal occult blood testing and colonoscopy in the surveillance of subjects at high risk of colorectal neoplasia

1995 ◽  
Vol 82 (3) ◽  
pp. 318-320 ◽  
Author(s):  
M. H. E. Robinson ◽  
O. Kronborg ◽  
C. B. Williams ◽  
K. Bostock ◽  
P. S. Rooney ◽  
...  
Keyword(s):  
High Risk ◽  
Colorectal Neoplasia ◽  
Occult Blood ◽  
Faecal Occult Blood Testing ◽  
Blood Testing ◽  
Faecal Occult Blood ◽  
Faecal Occult

scholarly journals Validation of Diagnosis and Procedure Codes for Revascularization for Peripheral Artery Disease in Ontario Administrative Databases

2021 ◽  
Vol 44 (2) ◽  
pp. E36-43
Author(s):  
Jean Jacob-Brassard ◽  
Mohammed Al-Omran ◽  
Thérèse A. Stukel ◽  
Muhammad Mamdani ◽  
Douglas S. Lee ◽  
...  
Keyword(s):  
Positive Predictive Value ◽  
Peripheral Artery Disease ◽  
Predictive Value ◽  
Population Based ◽  
Administrative Databases ◽  
Peripheral Artery ◽  
Predictive Values ◽  
Diagnosis Codes ◽  
Artery Disease ◽  
Procedure Codes

Purpose: To estimate the positive predictive value of diagnosis and procedure codes for open and endovascular revascularization for peripheral artery disease (PAD) in Ontario administrative databases. Methods: We conducted a retrospective validation study using population-based Ontario administrative databases (2005-2019) to identify a random sample of 600 patients who underwent revascularization for PAD at two academic centres, based on ICD-10 diagnosis codes and Canada Classification of Health Intervention procedure codes. Administrative data coding was compared to the gold standard diagnosis (PAD vs. non-PAD) and revascularization approach (open vs. endovascular) extracted through blinded hospital chart re-abstraction. Positive predictive values and 95% confidence intervals were calculated. Combinations of procedure codes with or without supplemental physician claims codes were evaluated to optimize the positive predictive value. Results: The overall positive predictive value of PAD diagnosis codes was 87.5% (84.6%-90.0%). The overall positive predictive value of revascularization procedure codes was 94.3% (92.2%-96.0%), which improved through supplementation with physician fee claim codes to 98.1% (96.6%-99.0%). Algorithms to identify individuals revascularized for PAD had combined positive predictive values ranging from 82.8% (79.6%-85.8%) to 95.7% (93.5%-97.3%). Conclusion: Diagnosis and procedure codes with or without physician claims codes allow for accurate identifi-cation of individuals revascularized for PAD in Ontario administrative databases.

RESCREENING OF A GROUP AT HIGH RISK FOR COLORECTAL NEOPLASIA USING IMMUNOCHEMICAL TESTS FOR FAECAL OCCULT BLOOD

1988 ◽  
Vol 58 (10) ◽  
pp. 791-794 ◽  
Author(s):  
Ronald Hunter ◽  
J. Anthony R. Williams ◽  
David W. Thomas ◽  
Margaret E. Coles ◽  
Robert Walsh ◽  
...  
Keyword(s):  
High Risk ◽  
Colorectal Neoplasia ◽  
Occult Blood ◽  
Faecal Occult Blood ◽  
Faecal Occult
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