Comparison of the Liaison® Calprotectin kit with a well established point of care test (Quantum Blue - Bühlmann-Alere®) in terms of analytical performances and ability to detect relapses amongst a Crohn population in follow-up.
BACKGROUND
Although colonoscopy associated with histopathological sampling remains the gold standard in the diagnostic and follow-up of inflammatory bowel disease (IBD), calprotectin is becoming an essential biomarker in gastroenterology. The aim of this work is to compare a newly developed kit (Liaison® Calprotectin - Diasorin®) and its two distinct extraction protocols (weighing and extraction device protocol) with a well established point of care test (Quantum Blue® - Bühlmann-Alere®) in terms of analytical performances and ability to detect relapses amongst a Crohn's population in follow-up.


METHODS
Stool specimens were collected over a six month period and were composed of control and Crohn's patients. Amongst the Crohn's population disease activity (active vs quiescent) was evaluated by gastroenterologists.


RESULTS
A significant difference was found between all three procedures in terms of calprotectin measurements (weighing protocol=30.3μg/g (median); stool extraction device protocol=36.9μg/g (median); Quantum Blue® (median)=63; Friedman test, P value=0.05). However, a good correlation was found between both extraction methods coupled with the Liaison® analyzer and between the Quantum Blue® (weighing protocol/extraction device protocol Rs=0.844, P=0.01; Quantum Blue®/extraction device protocol Rs=0.708, P=0.01; Quantum Blue®/weighing protocol, Rs=0.808, P=0.01). Finally, optimal cut-offs (and associated negative predictive values - NPV) for detecting relapses were in accordance with above results (Quantum Blue® 183.5μg/g and NPV of 100%>extraction device protocol+Liaison® analyzer 124.5μg/g and NPV of 93.5%>weighing protocol+Liaison® analyzer 106.5μg/g and NPV of 95%).


CONCLUSIONS
Although all three methods correlated well and had relatively good NPV in terms of detecting relapses amongst a Crohn's population in follow-up, the lack of any international standard is the origin of different optimal cut-offs between the three procedures.
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium. Electronic address: quentin.delefortrie@uclouvain.be.
Quentin
Q
Delefortrie
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium.
Patricia
P
Schatt
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium.
Alexandre
A
Grimmelprez
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium.
Patrick
P
Gohy
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium.
Didier
D
Deltour
Centre Hospitalier Régional du Val de Sambre, 5060 Auvelais, Belgium.
Geneviève
G
Collard
Clinique Notre Dame de Grâce, 6041 Gosselies, Chaussée de Nivelles 212, Belgium.
Patrick
P
Vankerkhoven
D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003113:Colonoscopy; D003424:Crohn Disease / Q000175:diagnosis*; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000737:chemistry*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D000067716:Point-of-Care Testing / Q000592:standards*; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D012008:Recurrence; D012680:Sensitivity and Specificity
D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D011933:Reagent Kits, Diagnostic
Calprotectin; Crohn's disease follow-up; Crohn's disease relapse screening; Inflammatory bowel disease; Liaison® Calprotectin; Quantum Blue®