Background and aim
Fecal calprotectin (FC) has been proposed in recent studies as a sensitive, specific biomarker
for the diagnosis of ulcerative colitis (UC). Hence, the present study sought to investigate the
efficacy of FC for the diagnosis and monitoring of UC, as well as to assess the correlation of
FC with other disease activity indexes.
Research design and methods
The present study included 96 consecutive patients who presented with lower gastrointestinal
complaints. Patients were classified into two groups: group I (which included patients with UC)
and group II (which included patients with irritable bowel syndrome); then, according to the
disease activity, group I was subdivided into the following: group Ia (which included patients
with active UC) and group Ib (which included only those patients of group Ia who were in the
remission stage of UC). For all patients, erythrocyte sedimentation rate and C-reactive protein
were determined; moreover, all patients underwent quantitative determination of calprotectin
in stool samples, abdominal ultrasonography, and complete colonoscopy with biopsies for the
histopathological examination to assess the disease severity by using the UC activity index
according to the Mayo endoscopic and Geboes histological scores. The diagnostic validity
of FC levels in correlation with Mayo Disease Activity Index (MDAI) was then investigated.
Results
FC levels showed highly significant increase in patients with active UC compared with inactive
UC and irritable bowel syndrome (524.17 ± 48.0 vs. 184.48 ± 3.33 and 47.17 ± 5.32 mg/kg,
respectively, P < 0.001). FC level has 100% accuracy, sensitivity, specificity, positive predictive
value, and negative predictive value in distinguishing UC patients from the control group at a
cutoff value of 140 mg/kg, but at a cutoff value of 223 mg/kg FC level shows 93.4% accuracy,
89.8% sensitivity, 97% specificity, 97.4% positive predictive value, and 55% negative predictive
value to distinguish the active phase from the remission phase of UC. In addition, there was a
statistically significant proportional correlation between FC and the MDAI, but the correlation
between FC and histological inflammatory activity statistically was more significant than with
MDAI (r = 0.75, P < 0.001).
Conclusion
FC level is an accurate, noninvasive biomarker in clinical practice with high specificity and
sensitivity for the diagnosis and monitoring of UC, as well as good marker for the evaluation
of disease activity. Therefore, it can be used as a monitoring test to assess medical response
and to predict clinical relapse of the disease. |
