Diagnostic accuracy of point of care faecal immunochemical testing using a portable high‐speed quantitative analyser for diagnosis in 2‐week wait patients

Abstract

Aim Laboratory‐based faecal immunochemical testing (FIT) is the gold standard for detecting the presence of blood in the stool. The aim was to perform a diagnostic accuracy study to confirm if a point of care (POC) analyser for FIT could be safely used as an adjunct in the triage and management of 2‐week wait (TWW) colorectal patients. Methods The Point of Care Faecal Immunochemical Testing (POC FIT) prospective observational cohort study was designed for TWW patients at a regional referral centre. Between July 2019 and March 2020, patients were invited to perform and bring a FIT sample to clinic. FIT was completed within the clinic appointment using a POC quantitative analyser that has a 2‐min processing time (QuikRead go®). Patients and clinicians were blinded to results within the clinic appointment. The results were compared with subsequent diagnostic outcomes. Faecal haemoglobin of <10 µg haemoglobin/g of faeces was considered a negative result. Sensitivities for colorectal cancer (CRC) and combined serious bowel disease (SBD) were calculated using this pre‐determined cut‐off. Results A total of 553 patients were included for analytical comparison with diagnostic outcomes. There were 14 (2.5%) patients with CRC and 52 (9.4%) with SBD. The sensitivities for CRC and SBD were 92.9% (95% CI 68.5%–98.7%) and 76.9% (95% CI 63.9%–86.3%) respectively. 379 (68.5%) patients had a negative FIT result (negative predictive value for CRC was 99.7%). Conclusions This POC FIT device is a useful adjunct to better manage TWW patients. The high observed sensitivity for CRC offers opportunities, within a single consultation, for improved triage and rationalization of investigation for those with bowel symptoms.

Role of the faecal immunochemical test in patients with risk-stratified suspected colorectal cancer symptoms: A systematic review and meta-analysis to inform the ACPGBI/BSG guidelines

“…The LoD of the HM-JACKarc and FOB Gold assays is <2 µg/g, 17 , 58 OC-Sensor <4 µg/g 33 and QuikRead go <10 µg/g. 34 Studies using the HM-JACKarc and OC-Sensor at these thresholds were combined within the LoD analyses. Subgroup analyses were performed to investigate the potential effects of analyser, threshold, presenting symptom cluster and recruitment location, on estimates of test accuracy.…”

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)

“…For those with dexterity difficulties in performing the test, digital rectal examination to obtain stool for FIT testing appears to offer similar accuracy to home performed tests 78. This might be combined with point-of-care testing to allow for discussion of an appropriate whole colon examination following a positive test with the clinician to support engagement with downstream testing for CRC in a single consultation 143…”

“… 78 This might be combined with point-of-care testing to allow for discussion of an appropriate whole colon examination following a positive test with the clinician to support engagement with downstream testing for CRC in a single consultation. 143 …”

Efficacy and accuracy of faecal sampling by a digital rectal examination for faecal immunochemical testing

“…For patients referred on the TWW in the United Kingdom, there is a requirement for patients to be seen by a specialist within two weeks from referral and for a diagnosis to be established within 28 days. If DRE were to be combined with POC testing, which has been shown to be comparable in sensitivity to laboratory-based testing, 9 then there is potential for a clinician to obtain a sample and have a result all within an initial consultation. This could better aid decision-making regarding referral or investigation choice.…”

“…The diagnostic accuracy of the QRG and its comparison to laboratory-based testing has previously been reported for this study. 9,10 A third sample was obtained via DRE and also analysed with the laboratory-based FOB Gold Wide ® to allow direct comparison with the sample collected by the patient.…”