FOCUS ON FIT 2 Foreword FIT for Purpose Faecal Immunochemical Tests (FIT) for Diagnosis of Significant Bowel Disease In June 2015, NICE published the NG12 guidelines and advocated the introduction of tests for “occult blood in faeces” for certain patients presenting in primary care with lower abdominal symptoms but with a low risk of colorectal cancer. This sparked much controversy regarding the different types of tests available for occult blood detection, since many hospital laboratories had discontinued the provision of guaiac-based tests and did not want to go back to this old technology with its very poor analytical and clinical sensitivity and specificity. Whilst newer quantitative Faecal Immunochemical Test (FIT) methods have been widely introduced for bowel screening, publications on the use of this methodology in assessment of patients with lower abdominal symptoms have been increasing since 2012. Unfortunately, these had not been part of the data review for the June 2015 NG12 publication. In consequence, NICE have now reviewed the evidence for FIT in this clinical setting and are due to publish new guidelines entitled: “Quantitative faecal immunochemical tests to assess symptomatic people who are at low risk of colorectal cancer in primary care”. This assessment is focused on peer-reviewed publications on quantitative FIT methods in this particular clinical setting. These publications are concerned with studies on symptomatic patients being planned or considered for colonoscopy on whom a FIT had been performed. INTRODUCTION Alpha Laboratories has been at the forefront of faecal testing in the UK for nearly 20 years. This was initially as the market leader for guaiac-based faecal occult blood testing in hospital laboratories. Tender wins for bowel screening in all four UK countries followed this, as each launched its own screening programme, assessing the average risk asymptomatic populations. Continuing to provide leading edge products, Alpha Laboratories has been awarded the first contract for quantitative FIT as the front line test in the Scottish Bowel Screening Programme. This will employ the Kyowa Medex HM-JACKarc system. England will also be moving to a quantitative FIT method in the NHS Bowel Cancer Screening Programme in the near future. The use of FIT in the assessment of the symptomatic is changing too, as more publications have demonstrated that the use of quantitative FIT as a “rule-out” test has benefits to clinicians, laboratories and patients. This ‘Focus on FIT’ publication summarises some recent progress and current thinking on the application of FIT in both symptomatic and screening populations. The quantitative FIT results were compared against the clinical findings. These publications identified that the FIT result could be used as a “rule out” test for significant colorectal disease (SCD), that is, colorectal cancer (CRC) plus higher risk adenoma (HRA: sometimes precursors of cancer) and inflammatory bowel disease (IBD: Crohn’s and ulcerative colitis), since they have a very high negative predictive value (NPV) for SCD. In fact, using a cut-off of <10 µg/g Hb/ faeces, the NPV was almost 100% for cancer and >90% for SCD. The NICE Diagnostics Assessment Committee has published a number of documents online, including the draft diagnostic guidance: www.nice.org.uk/guidance/indevelopment/ gid-dg10005/documents Differentiating patients with serious bowel disease from those with benign functional disorders, such as Irritable Bowel Syndrome (IBS), and minor colorectal disease such as haemorrhoids, hyperplastic polyps and simple diverticular disease, can be very challenging since the symptoms are very common and overlap in these conditions. The ability to use a simple, easy to use, inexpensive diagnostic test will provide additional assistance in determining the appropriate patient pathway for further investigation. Ahead of this publication, several hospitals and CCGs have already committed to the provision of FIT as a means of triaging all patients presenting in primary (and secondary) care with lower abdominal symptoms. Toilet Normal Abnormal Blood Mucus
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