Currently, 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. Two 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. A 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. We 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.
Bibliographical noteFunding Information:
Research funding: DJH is funded by a National Institute for Health Research post-doctoral fellowship. JRM is funded by a Medical Research Council Clinician Scientist Fellowship (grant number MR/P008348/1). OC Sensor FIT kits were produced by EIKEN Chemical Co Ltd, and provided by Mast (Mast Group Ltd. Mast House, Derby Road, Bootle, England, L20 1EA) for the study. HM-JACK FIT kits were produced by Hitachi Chemical Diagnostic Systems Co., Ltd (Tokyo, Japan) and provided by Alpha Laboratories (40 Parham Dr, Eastleigh SO50 4NU) for the study.
© 2020 2020 Walter de Gruyter GmbH, Berlin/Boston.
- bowel cancer
- colorectal cancer
- diagnostic accuracy
- faecal haemoglobin
- faecal immunochemical test (FIT)
- risk stratification