Kal ndi heterodimer, yomwe imapangidwa ndi mrp 8 ndi mrp 14. Imakhalapo mu neutrophils cytoplasm ndikuwonetsa pa cell nembanemba. Cal ndi mapuloteni a pachimake, ili ndi gawo lokhazikika pafupifupi sabata limodzi m'maso mwamisala, limatsimikiza kukhala chikhomo chotupa cham'mimba. Chidacho ndi chiyeso chosavuta, chowoneka chowoneka chomwe chimazindikira cal m'maso mwa anthu, chimazindikira kwambiri komanso kunyalanyaza kwambiri. Kuyesedwa kotengera kuchuluka kwa ma antibodies awiri a sandwich ndipo njira ya golide immunoromatographictricttiographic, imatha kupereka zotsatira mkati mwa mphindi 15.