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P166. Prospective evaluation of faecal tumour pyruvate kinase type M2 (M2-PK) in comparison to calprotectin in IBD patients

Y.M. Shastri1, N. Povse1, J. Stein2, 1J.W. Goethe University Hospital, Dept. of Medicine I-ZAFES, Frankfurt am Main, Germany, 2Crohn Colitis Zentrum Rhein-Main, Frankfurt am Main, Germany

Background

Determination of faecal concentration of the neutrophil granulocyte-derived protein calprotectin is a validated, non-invasive marker for the diagnosis, management and follow-up of patients with inflammatory bowel disease (IBD). Some recent studies have demonstrated test characteristics of the dimeric isoenzyme of pyruvate kinase, termed M2-PK, to make it possibly more appropriate for use as a marker of intestinal inflammation than for colorectal cancer screening. This the first study comparing these two markers in patients with IBD.

Methods

223 consecutive patients (125 female, 98 male), suffering from IBD and undergoing follow-up in our department, provided stool samples for the determination of M2-PK and calprotectin. These tests were performed using a commercial ELISA (Immundiagnostik, Germany) for calprotectin and a sandwich ELISA (ScheBo Biotech AG, Germany) for M2-PK. In addition, disease activity was assessed clinically and endoscopically. Technicians carrying out the tests were unaware of the patients' clinical profile.

Results

Patient and performance characteristics are presented in Tables 1 and 2.

Table 1. Patient characteristics for the two tests
Diagnosis (No.)Faecal calprotectinFaecal M2-PK
UC (71)  
 Active (50)4642
 Inactive (21)27
CD (152)  
 Active (102)9893
 Inactive (50)520
Table 2. Performance characteristics of tests
ParametersType of IBDFaecal calprotectinFaecal M2-PK
Sensitivity (%)UC92.0 (80.8–97.8)84.0 (70.9–92.8)
 CD96.1 (90.3–98.9)91.2 (83.9–95.9)
Specificity (%)UC90.5 (69.6–98.8)66.7 (43.0–85.4)
 CD90.0 (78.2–96.7)60.0 (45.2–73.6)
PPV (%)UC95.8 (85.8–99.5)85.7 (72.8–94.1)
 CD95.2 (89.0–98.4)82.3 (74.0–88.8)
NPV (%)UC82.6 (61.2–95.1)63.6 (40.7–82.8)
 CD91.8 (80.4–97.7)76.9 (60.7–88.9)
Values in brackets indicate confidence interval.

Conclusion

Our preliminary study indicates faecal calprotectin to have significantly better performance characteristics in comparison to faecal M2-PK. M2-PK was found to be a poor marker for the monitoring and follow-up of IBD patients. However, further studies are required on this topic.