In this section
September 2025
On 12th August 2025, Biochemistry transferred the faecal calprotectin (FCal) service to a new assay. This is yielding significantly greater workload capacity, which is resulting in improved turnaround times and overall service quality.
None of the current commercially available FCal assays yield directly comparable results. Hence, we have undertaken an extensive comparison study which has shown the new FCal assay (OC-Sensor Pledia) exhibits a positive bias when compared to the old assay (Immundiagnostik).
Based on this data, the negative cut-off has remained the same as previously at 100 µg/g, but cut-offs have changed for equivocal/positive results as follows:
| Result Classification | Old Assay (µg/g) | New Assay
(µg/g) |
| Negative | <100 | <100 |
| Equivocal | 100 – 250 | 100 – 350 |
| Positive | >250 | >350 |
Appropriate guidance is being applied to the new results to inform of these new cut-offs, and patients should be managed as per current pathways dependent upon the overall result classification.
For patients with known IBD where FCal is being used for monitoring purposes, results are approximately 30% higher in the equivocal/positive range by the new assay.