2 The technology

Faecal occult blood tests is a term used to describe both traditional manual guaiac faecal occult blood tests and automated faecal immunochemical tests. Faecal immunochemical tests have been developed as an alternative to guaiac faecal occult blood tests, because they are less likely to detect globin from upper gastrointestinal bleeding. Detecting faecal occult blood in low risk symptomatic patients helps to triage patients to secondary care and guide the decision for further investigation (see NICE recommendations).

Faecal immunochemical tests consist of a sample collection device, with a reagent and buffer, which is used to collect and stabilise the sample before it is analysed in a laboratory.

Table 1 contains more information on the 3 tests that are covered in the guidance.

Table 1 NICE-appraised faecal immunochemical tests and specifications

Device (company)

Analysers

Performance capacity (number of samples)

Sample collection device and volume

Company-suggested cut-off for detecting faecal occult blood

OC Sensor (Eiken Chemical/
MAST Diagnostics).

OC Sensor PLEDIA.

320 per hour, up to 200 per run.

Tubes, latex reagent and buffer; up to 10 mg of faeces.

10 micrograms of haemoglobin per 1 g of faeces (50 nanograms/ml) should be used for a symptomatic population.

OC Sensor iO analyser.

88 per hour, up to 20 samples per run.

HM‑JACKarc (Kyowa Medex/
Alpha Laboratories).

HM‑JACKarc analyser.

200 samples per hour, up to 80 samples per run.

Extel Hemo‑auto MC; up to 2 mg of faeces in 2 ml of buffer and latex agglutination reagent.

10 micrograms of haemoglobin per 1 g of faeces for symptomatic populations*.

FOB Gold (Sentinel/
Sysmex).

Various including: BioMajesty JCA‑6010/C, SENTiFIT270 and those supplied by Siemens, Beckman, Coulter and Abbott.

Varies depending on the analyser used.

SentiFIT pierce tube faecal collection device; up to 10 mg of faeces in 1.7 ml of buffer, and latex agglutination reagent.

Each laboratory should establish its own test cut-off according to the population the laboratory serves.

*The user needs to convert the results to micrograms of haemoglobin per 1 g of faeces. However, because the test uses 2 mg of sample and 2 ml of buffer, results reported as nanograms per ml convert directly to micrograms of haemoglobin per 1 g of faeces (that is, 10 nanograms per ml equals 10 micrograms of haemoglobin per 1 g of faeces).


This page was last updated: 17 January 2018