Comparison of faecal calprotectin using two collection and extraction strategies for the BÜHLMANN CALEX® Cap - possible implications for clinical cut-offs?
Author(s): Bruce H, Osypiw J, Prajapati-Jha G, O'Driscoll S, Brealey M, Benton SC
Publication: Ann Clin Biochem, 2023, Vol. 60, Page 236-242
PubMed ID: 36750426 PubMed Review Paper? No
Purpose of Paper
This paper compared calprotectin levels in case-matched feces that were collected by the patient in standard fecal containers with those that were collected by the patient directly into CALEX Cap devices and then shipped for analysis.
Conclusion of Paper
Overall, the median and interquartile range of protein calprotectin levels did not differ significantly between the two types of collection/shipment containers. When all fecal specimens were considered, calprotectin levels were strongly correlated between the two specimen collection/shipping containers, but the strength of the correlation was very weak among specimens with 100-250 µg calprotectin per gram of feces (considered a borderline result by the authors). The concordance of calprotectin concentration-based results (negative, borderline, elevated) between the two types of specimen collection/shipping containers was 77% for negative specimens, 84% for borderline specimens, and 99% for elevated specimens. Of the 25 specimens with discordant results between the two collection/shipping containers, the higher calprotectin concentration occurred in specimens that were collected and shipped in the CALEX Cap device for 22 specimens (11 specimens were borderline versus negative, 3 were elevated versus negative, and 9 were elevated versus borderline). The authors inferred that collecting and shipping feces in CALEX Cap devices may stabilize protein levels of calprotectin.
Studies
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Study Purpose
This study compared calprotectin levels in case-matched feces specimens that were collected by the patient and shipped in standard fecal containers with those that were collected by the patient directly into CALEX Cap devices. Fecal specimens were self-collected by 91 patients (5-92 years of age, diagnosis not specified) into CALEX Cap collection devices and standard fecal containers. Specimens were transported to the laboratory by pathology transport (3 days, no further details provided). Calprotectin was extracted from feces in standard tubes after transferring the specimens to a CALEX Cap device. Specimens in CALEX devices were centrifuged at 3000 g, and the supernatant was transferred to a new tube prior to analysis. Calprotectin levels were quantified using a Cobas 8000 c702 module. Specimens were classified as negative if the calprotectin concentration was <100 μg/g feces, borderline if the calprotectin concentration was 100-250 μg/g feces, and elevated if the calprotectin concentration was >250 μg/g feces.
Summary of Findings:
Overall, the median and interquartile range of protein calprotectin levels did not differ significantly between the two types of collection/shipment containers. Calprotectin levels were strongly correlated between the two types of specimen collection/shipping container (R2=0.70) in the whole dataset, but the strength of the correlation was very weak among specimens with 100-250 µg calprotectin per gram of feces (R2=0.08). Concordance in calprotectin concentration-based results between the two types of specimen collection/shipping containers was 77% for negative specimens, 84% for borderline specimens, and 99% for elevated specimens. Of the 25 specimens with discordant results between the two collection/shipping containers, the higher calprotectin concentration occurred in specimens that were collected and shipped in the CALEX Cap device for 22 specimens (11 specimens were borderline versus negative, 3 were elevated versus negative, and 9 were elevated versus borderline). The authors inferred that collecting and shipping feces in CALEX Cap devices may stabilize calprotectin.
Biospecimens
Preservative Types
- Other Preservative
- None (Fresh)
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Protein Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Specimen transport duration/condition In Calex Cap device
In standard fecal container
Biospecimen Preservation Type of fixation/preservation None (fresh)
Calex Cap device