label: Decreased circulating terminal complement component concentration
label_lc: decreased circulating terminal complement component concentration
description: "Concentration below the lower limit of normal of one or more components of the the terminal membrane attack complex (MAC) portion of complement, which represents the lytic, pore-forming part of the system. The MAC comprises seven components: C5b, C6, C7, C8 (a heterotrimer composed of C8alpha, C8beta and C8gamma) and multiple copies of C9."