iFOBT (Stool Cancer Screening)

An immunochemical faecal occult blood test (iFOBT) that detects human haemoglobin in stool samples using antibodies specific to the globin portion of haemoglobin. Unlike older guaiac-based tests, the iFOBT does not react to dietary meat or plant peroxidases, eliminating false positives from food. It is the recommended first-line screening for colorectal cancer in asymptomatic adults aged 50 and above.

Colorectal cancer is the second most common cancer in Germany, yet it is one of the most preventable when detected early through systematic screening. The immunochemical faecal occult blood test detects microscopic quantities of human haemoglobin in stool — a hallmark of colorectal polyps and early-stage tumours that bleed intermittently. The test uses monoclonal antibodies targeting the globin component of human haemoglobin, which degrades as it passes through the upper gastrointestinal tract, making the iFOBT specific to lower GI bleeding. This specificity is a major advantage over older guaiac-based tests (gFOBT), which react to any peroxidase activity including that from red meat, raw vegetables, and certain medications. The iFOBT requires no dietary restrictions before sample collection, significantly improving patient compliance. A single stool sample is collected at home using the provided collection device and returned to the laboratory. At SYNLAB München Zentrum, iFOBT analysis is performed using quantitative immunoturbidimetric assay, with a cut-off calibrated to German screening programme standards. A positive result triggers a recommendation for diagnostic colonoscopy to identify and remove any polyps or lesions. The iFOBT should be repeated annually as part of a routine screening programme, as interval cancers can develop between tests. Results are typically available within one to three working days.