High-sensitivity CRP (hs-CRP) measures CRP levels that were previously thought to be under the detection limit. In pediatric IBD, this kind of highly sensitive marker is needed for the detection of the presence of inflammation.

Inflammatory bowel disease is a chronic, relapsing, and remitting disease of the gastrointestinal tract characterized by diarrhea, abdominal pain, and weight loss. CRP is an acute phase protein produced by liver that is used in the diagnosis of inflammatory disorders. Serum hs-CRP can be analyzed using enzyme linked immunoassays (ELISA) kits. A team from Finland investigated the association between hs-CRP and clinical and histological activity in pediatric IBD patients, and evaluated the effect of glucocorticoid treatment on the hs-CRP levels.

The serum samples from 39 Finnish children with IBD were analyzed using a human C-reactive protein Instant ELISA kit (Bender MedSystems GmbH, Vienna, Austria; www.bendermedsystems.com). A further 22 children with IBD and followed for acute response to glucocorticoids, and 33 pediatric non-IBD patient were also tested. The hs-CRP Instant ELISA kit has an intra-assay coefficient of variation (C.V.) of 6.9%, and an interassay C.V. of 13.1% and detection limit of 3 × 10^-6 mg/L.

The study, carried out at the University of Helsinki (Helsinki, Finland), showed that standard CRP test is negative in a considerable number of pediatric patients with active IBD and the routine measurement of CRP is thus not informative enough. The hs-CRP test detects low levels of CRP, but disappointingly, it does not help to distinguish children with active intestinal inflammation from those with quiescent disease or those responding to glucocorticoid treatment from nonresponders. Interestingly, the levels of hs-CRP correlated with the presence of ileal inflammation.

This study reinforces the concept that a significant number of pediatric patients with active IBD may present with CRP levels that are under the detection limit. Here, standard CRP was under the detection limit of 5 mg/L in 60% of the young patients with active colitis. All patients with undetectable standard CRP had measurable hs-CRP levels, but there was no cut-off value for low CRP values with which to differentiate active and dormant disease. The results of the clinical investigation were published on June 21, 2010, in the World Journal of Gastroenterology.

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Bender MedSystems GmbH
University of Helsinki