| 1. The FOB screening test uses a CE-marked FIT method (FA280 Orienter Fully Automated Digital Feces Analyzer) with anti-human hemoglobin antibodies to detect blood in stool samples. Results are not affected by the patient's diet. |
| 2. Positive FOB results are not diagnostic for colorectal cancer. The HK Colorectal Cancer Screening Program (2016 to 2022) screened 330,000 participants with 12.7% positive results. Follow-up colonoscopy found adenocarcinoma cancer in 5.2% and adenoma in 58.9% of the patients with positive results. |
| 3. Other possible causes of positive results and sometimes visible blood include diverticular disease, polyps, haemorrhoids, inflammatory bowel disease, ulcers, anal fissures, and inflammation. FOB tests for these causes should be performed after the bleeding has ceased or, by other testing methods (e.g., colonoscopy). Therefore, clinical history and examination are helpful. |
| 4. Stool samples are not homogenous, so quantitative values are not reproducible with different sampling areas in the same stool, nor indicate the severity of disease. However, should a quantiative test be required, it is available under test code U014Q. |
| 5. Follow up positive results with other tests as clinically indicated. |
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| References: |
| 1. CHP, DH, HKSARG. Colorectal Cancer Screening Programme Progress Report of the Screening Outcome for Participants Enrolled between 28 September 2016 and 31 December 2022. Accessed 250318. https://www.colonscreen.gov.hk/sites/default/files/pdf/CRCSP_progress_report_DEC_2022_FINAL.pdf |
| 2. FA280 Orienter Fecal Occult Blood (FOB) package insert 202503.E |