Choice of faecal immunochemical test matters: comparison of OC-Sensor and HM-JACKarc, in the assessment of patients at high risk of colorectal cancer

Abstract

ObjectivesCurrently, NICE recommends the use of faecal immunochemical test (FIT) at faecal haemoglobin concentrations (f-Hb) of 10 μg Hb/g faeces to stratify for colorectal cancer (CRC) risk in symptomatic populations. This f-Hb cut-off is advised across all analysers, despite the fact that a direct comparison of analyser performance, in a clinical setting, has not been performed.MethodsTwo specimen collection devices (OC-Sensor, OC-S; HM-JACKarc, HM-J) were sent to 914 consecutive individuals referred for follow up due to their increased risk of CRC. Agreement of f-Hb around cut-offs of 4, 10 and 150 µg Hb/g faeces and CRC detection rates were assessed. Two OC-S devices were sent to a further 114 individuals, for within test comparisons.ResultsA total of 732 (80.1%) individuals correctly completed and returned two different FIT devices, with 38 (5.2%) CRCs detected. Median f-Hb for individuals diagnosed with and without CRC were 258.5 and 1.8 µg Hb/g faeces for OC-S and 318.1 and 1.0 µg Hb/g faeces for HM-J respectively. Correlation of f-Hb results between OC-S/HM-J over the full range was rho=0.74, p<0.001. Using a f-Hb of 4 µg Hb/g faeces for both tests found an agreement of 88.1%, at 10 µg Hb/g faeces 91.7% and at 150 µg Hb/g faeces 96.3%. A total of 114 individuals completed and returned two OC-S devices; correlation across the full range was rho=0.98, p<0.001.ConclusionsWe found large variations in f-Hb when different FIT devices were used, but a smaller variation when the same FIT device was used. Our data suggest that analyser-specific f-Hb cut-offs are applied with regard to clinical decision making, especially at lower f-Hb.

Faecal immunochemical testing (FIT) in patients with signs or symptoms of suspected colorectal cancer (CRC): a joint guideline from the Association of Coloproctology of Great Britain and Ireland (ACPGBI) and the British Society of Gastroenterology (BSG)

“…5 To date there are only two peer-reviewed publications that have directly compared results obtained on two different FIT analytical systems when patients have taken samples from the same bowel motion in a symptomatic pathway. 75 101 In the first study 75 732 patients returned both an OC-Sensor and an HM-JACKarc collection device. They had been instructed to collect samples into each device from the same bowel motion.…”

“…A meta-analysis to inform the guidelines identified seven studies (n=18 264) that used the NG12 definition of symptomatic patients and colonoscopy or CTC as the reference standard 14 51 62 72 75–77. The summary estimates of sensitivity and specificity were 88.7% (95% CI 84.4% to 92.0%) and 78.5% (95% CI 73.0% to 83.2) at a cut-off of 10 µg/g.…”

“…To date there are only two peer-reviewed publications that have directly compared results obtained on two different FIT analytical systems when patients have taken samples from the same bowel motion in a symptomatic pathway 75 101…”

Priority stratification for colonoscopy based on two-sample faecal immunochemical test screening: results from a cross-sectional study at an endoscopy clinic in Japan

“…The guidelines for colorectal cancer screening in Japan only recommend the two-sample FIT as standard, with no specific kits or cut-off values. As differences in FIT kit features and thresholds have been known to affect screening performance, 29 these variations are certainly a limitation of our study. However, a notable difference in the results between two-positive and one-positive FIT groups shown in our study suggests a common trend irrespective of kits brand.…”

Evaluation of the Sentinel-FOB gold faecal immunochemical test for the presence of haemoglobin using the automated Roche Cobas 8000 system

“…Godber et al reported a significant lower sensitivity of 68.9% and a specificity of 80.2% using a cutoff of 10 μg/g [ 23 ]. Further, Chapman et al [ 27 ] reported a sensitivity of 84% and a specificity of 78% in patients with increased risk of CRC.…”