P059 Test of stability in stool extracts for F-calprotectin. (16th January 2018)

• Record Type: Journal Article
• Authors: Aardal Eriksson, E; Andersson, J
• Is Part Of: Journal of Crohn's and colitis. Volume 12:Number 1(2018:Jan.)Supplement 1
• Page Start: S122
• Page End: S123
• Publication Date: 2018-01-16
• Subjects: Inflammatory bowel diseases -- Periodicals; 616.344005
• DOI: 10.1093/ecco-jcc/jjx180.186
• Languages: English
• ISSNs: 1873-9946

Abstract

Abstract: Background: The DiaSorin LIAISON® calprotectin assay is an in vitro diagnostic chemiluminescent sandwich immunoassay using two monoclonal antibodies for capture and detection of calprotectin. Calprotectin is a heterocomplex composed of the calcium and zinc binding proteins S100A8 and S100A9. It constitutes more than 60% of total protein in the cytosol of neutrophils, which infiltrate the intestinal mucosa as part of the inflammatory response. The non-invasive measurement of faecal calprotectin is considered a useful screening tool for differentiating inflammatory bowel disease (IBD) from non-organic diseases in conjunction with clinical information and other diagnostic procedures. The concentration of calprotectin in stool reflects the number of neutrophils present and therefore provides an indicator of the severity of intestinal inflammation. Calprotectin is extracted from stool samples with an extraction buffer and the stool extracts processed by the LIAISON® Calprotectin Stool Extraction Device (SED) are stable for up to 6 h at 2–8°C prior to testing. The Department of Clinical Chemistry, Linköping University Hospital receive about 11000 referrals for faecal Calprotectin on a yearly basis. Because of the short stability, the extraction procedure cannot be performed until assay quality controls are accepted. The aim of this study was to test the stability of stool extracts processed by the SED in order to simplify the laboratory pre-analytical process and optimise the turnaround time for the LIAISON® Calprotectin Assay. Methods: Extraction was performed with SED from 30 fresh stool samples and 20 frozen samples previously assayed in routine. The extracts were analysed with LIAISON® Calprotectin Assay according to a pre-set time schedule for up to 3 days after extraction for comparison with the original result. For five samples two extractions were performed from fresh stool, one centrifuged and decanted to another tube and the other stored in SED at 2–8°C. Both extracts were assayed once daily for 7 days. Results: No statistically significant difference was shown between the original calprotectin results and those obtained after 3 days. However, samples with elevated original calprotectin levels re-extracted from frozen material tended to show higher values than samples re-extracted from fresh material. No statistically significant difference was shown between calprotectin results over seven days for the two extract storage procedures. Conclusions: Stool extracts for Calprotectin analysis with DiaSorin, LIAISON® were stable for at least 3 days in the SED without further handling, and that the pre-analytical procedure can be simplified.