Automated immunochemical quantitation of haemoglobin in faeces collected on cards for screening for colorectal cancer.
ABSTRACT Simple card collection systems are becoming available for faecal immunochemical tests (FITs) as well as guaiac faecal occult blood tests (gFOBTs). FITs are now obtainable that allow quantitation of haemoglobin, so that the analytical detection limit can be set to give a positivity rate that is manageable in terms of the available colonoscopy. A combination of a card collection device and an automated FIT analytical system could be advantageous.
The quantitation of haemoglobin in samples collected on cards with a new analytical system and the relationship between faecal haemoglobin concentration and pathology were investigated in a cohort of gFOBT-positive individuals.
All groups had large ranges of haemoglobin concentration and there was overlap between the groups. Median haemoglobin concentrations in participants with normal findings on colonoscopy (167), diverticular disease (43), hyperplastic polyps (41), low risk adenoma (63), higher risk adenoma (35) and cancer (27) were 13.5, 15.6, 16.8, 15.2, 65.6 and 168.9 ng/ml haemoglobin, respectively. Those with diverticular disease, hyperplastic polyps and low risk adenoma were not significantly different from the normal group (p>0.2), but those with higher risk adenoma had significantly higher concentrations (p<0.001), as did those with cancer (p<0.001). Receiver operating characteristic analysis demonstrates that the cut-off concentration can be set to give appropriate clinical characteristics; optimum sensitivity and specificity are achieved at 26.7 ng/ml.
The haemoglobin in faeces on simple FIT card collection devices can be immunoturbidimetrically analysed quantitatively, and the concentration relates to the presence or absence of significant neoplastic disease.
Chapter: Noninvasive Screening Tests[show abstract] [hide abstract]
ABSTRACT: During the past 2 decades, colorectal cancer (CRC) incidence and mortality rates in the United States have declined in part due to screening. The most recent Behavioral Risk Factor Surveillance System (BRFSS) survey data posted on the CDC website indicate that, in 2008, 52% of adults aged 50 years or older had a fecal occult blood test (FOBT) within the previous year or a lower endoscopy (sigmoidoscopy or colonoscopy) within the previous 5 years . In fact, the majority had either a sigmoidoscopy or colonoscopy (42.3% of respondents), while just 15.3% were screened with a stool test . In 2006, 60.8% of respondents to the same survey reported having had an FOBT within the year preceding the survey or a lower endoscopy within the preceding 10 years, an increase from 56.8% in 2004, 53.9% in 2002, and 53.1% in 2001 [2, 3]. These surveys show that while lower endoscopy screening has increased (43.4% in 2001, 44.8% in 2002, 50.1% in 2004, and 55.7% in 2006), FOBT screening has declined (23.5% in 2001, 21.6% in 2002, 18.5% in 2004, and 16.2% in 2006) [2, 3]. The 2000 National Health Interview Survey (NHIS) found that 49.7% of adults ≥50 years never had CRC testing; only 37.1% were current for their CRC screening . In 2003, the NHIS survey reported higher rates of colonoscopy screening (32.2% in men and 29.8% in women) than FOBT screening (16.1% in men and 15.3% in women) or sigmoidoscopy screening (7.6% in men and 5.9% in women) . In general, self-reported CRC screening rates from all national surveys, which are probably overestimates of actual screening, have increased from less than 25% in the late 1980s to about 60% in 2006, mainly due to increased use of screening colonoscopy . KeywordsFecal occult blood test-Immunochemical-Fecal DNA04/2011: pages 123-150;
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ABSTRACT: Immunochemical faecal occult blood testing (FIT) provides quantitative test results, which allows optimisation of the cut-off value for follow-up colonoscopy. We conducted a randomised population-based trial to determine test characteristics of FIT (OC-Sensor micro, Eiken, Japan) screening at different cut-off levels and compare these with guaiac-based faecal occult blood test (gFOBT) screening in an average risk population. A representative sample of the Dutch population (n=10 011), aged 50-74 years, was 1 : 1 randomised before invitation to gFOBT and FIT screening. Colonoscopy was offered to screenees with a positive gFOBT or FIT (cut-off 50 ng haemoglobin/ml). When varying the cut-off level between 50 and 200 ng ml(-1), the positivity rate of FIT ranged between 8.1% (95% CI: 7.2-9.1%) and 3.5% (95% CI: 2.9-4.2%), the detection rate of advanced neoplasia ranged between 3.2% (95% CI: 2.6-3.9%) and 2.1% (95% CI: 1.6-2.6%), and the specificity ranged between 95.5% (95% CI: 94.5-96.3%) and 98.8% (95% CI: 98.4-99.0%). At a cut-off value of 75 ng ml(-1), the detection rate was two times higher than with gFOBT screening (gFOBT: 1.2%; FIT: 2.5%; P<0.001), whereas the number needed to scope (NNscope) to find one screenee with advanced neoplasia was similar (2.2 vs 1.9; P=0.69). Immunochemical faecal occult blood testing is considerably more effective than gFOBT screening within the range of tested cut-off values. From our experience, a cut-off value of 75 ng ml(-1) provided an adequate positivity rate and an acceptable trade-off between detection rate and NNscope.British Journal of Cancer 04/2009; 100(7):1103-10. · 5.08 Impact Factor
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ABSTRACT: Several colorectal cancer-screening tests are available, but it is uncertain which provides the best balance of risks and benefits within a screening programme. We evaluated cost-effectiveness of a population-based screening programme in Ireland based on (i) biennial guaiac-based faecal occult blood testing (gFOBT) at ages 55-74, with reflex faecal immunochemical testing (FIT); (ii) biennial FIT at ages 55-74; and (iii) once-only flexible sigmoidoscopy (FSIG) at age 60. A state-transition model was used to estimate costs and outcomes for each screening scenario vs no screening. A third party payer perspective was adopted. Probabilistic sensitivity analyses were undertaken. All scenarios would be considered highly cost-effective compared with no screening. The lowest incremental cost-effectiveness ratio (ICER vs no screening euro 589 per quality-adjusted life-year (QALY) gained) was found for FSIG, followed by FIT euro 1696) and gFOBT (euro 4428); gFOBT was dominated. Compared with FSIG, FIT was associated with greater gains in QALYs and reductions in lifetime cancer incidence and mortality, but was more costly, required considerably more colonoscopies and resulted in more complications. Results were robust to variations in parameter estimates. Population-based screening based on FIT is expected to result in greater health gains than a policy of gFOBT (with reflex FIT) or once-only FSIG, but would require significantly more colonoscopy resources and result in more individuals experiencing adverse effects. Weighing these advantages and disadvantages presents a considerable challenge to policy makers.British Journal of Cancer 02/2012; 106(5):805-16. · 5.08 Impact Factor