Evaluation of the performance of a fecal tumor M2-PK rapid kit using stool specimens for detection of colorectal tumors

Background. In gastrointestinal tumors, only subunits of pyruvate kinase isoenzyme type M2 are detectable, and mainly in the dimeric form termed tumor M2-PK. A rapid test for the detection of M2-PK in stool has been developed. We evaluated the performance of the M2-PK rapid kit for the detection of colorectal tumors compared with colonoscopy. Design. Stool specimens (n=268) were obtained from patients who had a fecal occult blood test and colonoscopy performed for clinical evaluation or routine health checkup. Collected stool specimens were kept frozen at -20°C until testing. The fecal tumor M2-PK test was performed using a ScheBo M2-PK Quick test (ScheBo®•Biotech AG, Giessen, Germany). Results. A total of 236 patients were analyzed, including 87 with tubular adenoma and 126 controls. In tumor M2-PK testing, 37 of 87 tubular adenoma specimens (42.5%) and 2 of 4 sessile serrated adenoma specimens (50%) tested positive. The specificity of the M2-PK rapid test was 87.3%. Conclusion. The tumor M2-PK test demonstrated moderate sensitivity for detection of colorectal adenoma. M2-PK test could be considered as a useful point-of-care testing device for detection of colorectal tumors.