Mean faecal calprotectin values in FDRs according to IBD antibody and radiographic status
| FDR status | Mean fCal (mcg/g) | p Value |
| Positive for sacroiliitis (SI) findings in MRI | 74.65 | 0.18 |
| Negative for sacroiliitis (SI) findings in MRI | 40.85 | |
| Positive for IBD antibodies | 54.64 | 0.63 |
| Negative for IBD antibodies | 42.69 | |
| Negative for SI and IBD antibodies | 37.06 |
fCal, faecal calprotectin; FDR, first-degree relative; IBD, inflammatory bowel disease.