Quantitative Faecal Hb (FHb)

Purpose:
Faecal immunochemical tests (FIT) are designed to detect small amounts of blood in stool samples (faecal occult blood) using antibodies specific to human haemoglobin (Hb). These tests are recommended by NICE to guide colorectal cancer pathway referral in primary care. [DG56 – quantitative faecal immunochemical testing to guide colorectal cancer pathway referral in primary care] and in NICE guideline [NG12]: Suspected cancer: recognition and referral. FIT is also recommended by the UK National Screening Committee and has replaced gFOBT as part of the testing strategy for the UK Bowel Cancer Screening Programmes.

NICE DG56: Recommendations (2023) and NICE NG12: Recommendations 1.3 Lower gastrointestinal tract cancers (updated 2023)
1.1 Quantitative faecal immunochemical testing (FIT) using HM‑JACKarc or OC‑Sensor is recommended to guide referral for suspected colorectal cancer in adults: with an abdominal mass, or with a change in bowel habit, or with iron-deficiency anaemia, or aged 40 and over with unexplained weight loss and abdominal pain, or aged under 50 with rectal bleeding and either of the following unexplained symptoms: abdominal pain, weight loss, or aged 50 and over with any of the following unexplained symptoms: rectal bleeding, abdominal pain, weight loss, or aged 60 and over with anaemia even in the absence of iron deficiency.
FIT should be offered even if the person has previously had a negative FIT result through the NHS bowel cancer screening programme. People with a rectal mass, an unexplained anal mass or unexplained anal ulceration do not need to be offered FIT before referral is considered.
1.2 Refer adults using a suspected cancer pathway referral (as outlined in NICE’s guideline on suspected cancer) for colorectal cancer if they have a FIT result of at least 10 μg of haemoglobin / g of faeces.
1.5 Further research is recommended to: determine the clinical impact of using:
thresholds higher than 10 micrograms of haemoglobin per gram of faeces to guide referral, dual FIT, FIT in people aged under 40.
1.6 Further research is recommended on the effectiveness of: FOB Gold, IDK Hemoglobin ELISA, IDK Hemoglobin/Haptoglobin Complex ELISA, DK TurbiFIT, NS‑Prime, QuikRead go iFOBT.

UK National Screening Committee (2018) recommendation
Screening for bowel cancer should be offered every 2 years to men and women between the ages of 50 and 74 in the UK using the faecal-immunochemical test (FIT).

The Quantitative FIT EQA programme is designed to assess performance of laboratories undertaking FIT as part of the diagnostic investigation of colorectal cancer in symptomatic patients and in the assessment of specialist centres using FIT for the asymptomatic population screening for colorectal cancer.

Scope:
The base material is organic material which closely mirrors the basic constituents of human faeces to which a known quantity of Hb (as human whole blood) is added. Material at a range of Hb concentrations is prepared to cover the pathological and analytical range for FIT including samples at or near the clinical cut-off of 10 ug Hb /g used for symptomatic testing pathways and the higher cut offs used in asymptomatic population screening programmes. The homogeneous material is dispensed aseptically into buffered vials specific to each instrument manufacturer.

The three samples per distribution is designed to assess laboratory and method performance, including linearity, bias, and within batch imprecision.

Key Features:

Material closely mirrors the basic constituents of human faeces.
FIT samples are pre loaded into buffered collection tubes specific to each instrument.
Covers the pathological and analytical range for quantitative FIT automated analysers.
Samples challenging clinically relevant cut-offs for symptomatic testing pathways.