The Combined Value of Faecal Haemoglobin and Calprotectin in Diagnosis of Colorectal Cancer in Symptomatic Patients Referred to Colonoscopy

Aim: To investigate the diagnostic value of a combined analyses of faecal immunological haemoglobin (FIT) and faecal calprotectin (FC) in detection of colorectal cancer (CRC).

Methods: Out-patients (n=1440) referred to the endoscopy unit were analysed for FIT and FC in stool samples collected before the colonoscopy bowel preparation. The samples were collected from one defecation by the patients at home. Patients with IBD were excluded leaving stool samples from 1133 patients for further analyses. FIT was analysed using the immunological Analyse F.O.B Test and FC was analysed using the CALPRO® Calprotectin Elisa Test. Sensitivity and specificity to detect CRC was calculated for the individual tests, as well as for combined FIT/FC tests.

Results: Out of the included patients, 38 were diagnosed with CRC, 9 with high grade dysplasia (HGD), and 133 with low grade dysplasia (LGD). FIT was analysed in 673 (59.4%), FC in 1021 (90.1%) and both FIT and FC in 561 (49.5%) patients. A ROC curve analysis showed that the most accurate cut-off level for FC in detecting CRC in our study was 105.5 μg/g. The sensitivity for CRC when using FIT, FC (cut-off > 100 μg/g) and the combination of FIT and FC (at least one positive test) was 65.5%, 74.1% and 94.4%, respectively. The corresponding specificity was 84.8%, 74.9% and 68.3%, respectively.

Conclusion: Combined analyses of FIT and FC improved sensitivity for detection of CRC. Further studies in larger cohorts are required to find the optimal cut-off levels for different combinations of tests.

Keywords: Colorectal cancer; F-Calprotectin; F-Hb: Faecal markers; Screening markers