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Effect of faecal calprotectin assay variability on the management of inflammatory bowel disease and potential role of faecal S100A12
  1. Simon John Whitehead1,
  2. Clare Ford1,
  3. Rousseau Mariano Gama1,2,
  4. Ala Ali3,
  5. Brian McKaig4,
  6. Jenna Louise Waldron5,
  7. Helen Steed4,
  8. Matthew James Brookes4
  1. 1 Department of Clinical Chemistry, New Cross Hospital, Wolverhampton, UK
  2. 2 Research Institute, Healthcare Sciences, Wolverhampton University, Wolverhampton, UK
  3. 3 Department of Gastroenterology, City Hospital, Birmingham, UK
  4. 4 Department of Gastroenterology, New Cross Hospital, Wolverhampton, UK
  5. 5 Department of Clinical Biochemistry, City Hospital, Birmingham, UK
  1. Correspondence to Dr Simon John Whitehead, Department of Clinical Biochemistry, New Cross Hospital, Wednesfield Rd, Wolverhampton WV10 0QP, UK; simonwhitehead{at}nhs.net

Abstract

Aims To prospectively evaluate whether between-assay variability of different faecal calprotectin (f-Cp) assays influences diagnostic accuracy for inflammatory bowel disease (IBD) in a cohort of patients with confirmed IBD and irritable bowel syndrome (IBS). To also evaluate the diagnostic accuracy of faecal S100A12 (f-S100A12) against f-Cp in the same patient cohort and assess whether f-S100A12 offers additional diagnostic value.

Methods F-Cp using four commercially available f-Cp assays, f-S100A12 and blood biomarkers were measured in patients, recruited from the local IBD clinic, who had established IBS or active ulcerative colitis (UC) and Crohn’s disease (CD). Diagnostic sensitivities and specificities for each assay and biomarker were calculated and compared.

Results Median f-Cp levels in all assays were significantly higher in UC (347–884 µg/g; n=28) and CD (377–838 µg/g; n=15) compared with IBS (6–27 µg/g; n=17). Sensitivities and specificities at 50 µg/g were 94%–100% and 82%–100%, respectively. Median f-S100A12 levels were significantly higher in UC (81.0 µg/g; IQR 38.3–159.8) and CD (47.2 µg/g; IQR 5.3–108.9) compared with IBS (0.7 µg/g; IQR 0.5–0.8). At 2.8 µg/g, f-S100A12 had a sensitivity of 97% and specificity of 94%. The blood biomarkers demonstrated sensitivities and specificities of 44%–63% and 80%–92%, respectively.

Conclusions The diagnostic sensitivity of the calprotectin assays was similar despite inter-kit variability in absolute values. There is a need for f-Cp assay standardisation, but in its absence assay-specific cut-off values may optimise their diagnostic performance. F-S100A12 demonstrated comparable sensitivity and specificity to f-Cp and although a research tool at present, may have a future role to play in the diagnosis and management of these patients.

  • S100A12
  • faecal markers
  • calprotectin
  • IBD
  • IBS

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Footnotes

  • Handling editor Tahir S Pillay

  • Contributors SJW, CF, RG and MJB conceived and designed the study. SJW, AA, BM, JW and MJB were involved in patient recruitment and data acquisition. SJW, CF, MJB, RG, HS were involved in data analysis and interpretation. SJW wrote the first draft of the paper. All authors were involved in the reviewing and editing of the manuscript.

  • Competing interests SJW was an invited speaker at a Bühlmann user group meeting (expenses paid) hosted by Alpha Laboratories (UK suppliers of the Bühlmann Laboratories assay). The rest of the authors have no competing interest to declare.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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