Cal yog ib qho heterodimer, uas muaj MRP 8 thiab MRP 14. Nws muaj nyob rau hauv neutrophils cytoplasm thiab qhia tawm ntawm mononuclear cell membranes. Cal yog cov protein theem mob hnyav, nws muaj ib theem ruaj khov zoo li ib lub lim tiam hauv tib neeg cov quav, nws tau txiav txim siab tias yog ib qho cim qhia txog kab mob plab hnyuv. Lub pob khoom yog ib qho kev xeem yooj yim, pom tau semiqualitative uas ntes tau cal hauv tib neeg cov quav, nws muaj kev rhiab heev thiab muaj zog tshwj xeeb. Qhov kev xeem raws li kev tshwj xeeb siab ob chav antibodies sandwich reaction principle thiab kub immunochromatographic assay analysis technics, nws tuaj yeem muab cov txiaj ntsig hauv 15 feeb.