Cal yog ib tug heterodimer, uas yog tsim los ntawm MRP 8 thiab MRP 14. Nws muaj nyob rau hauv neutrophils cytoplasm thiab qhia rau mononuclear cell membranes. Cal yog mob theem proteins, nws muaj ib tug ruaj khov theem txog ib lub lim tiam nyob rau hauv tib neeg faeces, nws txiav txim siab los ua ib tug inflammatory plob tsis so tswj kab mob. Cov khoom siv yog ib qho yooj yim, pom qhov kev ntsuam xyuas uas pom cal nyob rau hauv tib neeg faeces, nws muaj siab nrhiav tau rhiab heev thiab muaj zog tshwj xeeb. Qhov kev ntsuam xyuas raws li qhov tshwj xeeb ntawm ob chav tshuaj tiv thaiv kab mob Sandwich cov ntsiab lus thiab cov kev ntsuas kub immunochromatographic tshuaj ntsuam xyuas, nws tuaj yeem muab cov txiaj ntsig tsis pub dhau 15 feeb.