Table 1.

Complement components and potential analytes by pathway.

Section	Classical Pathway	Lectin Pathway	Alternative Pathway	Terminal Pathway
Section 1. Components Individual Component PID: Absent Dysregulation: Low Activation: Multiple Low Inhibition: Normalize	C1 (C1q, C1r, C1s)	MBL	C3(H2O), Properdin
		Ficolin 1,2,3
		Collectins
	C2	C2	Factor B, Factor D	C5
	C4, C3	C4, C3	Factor D	C6, C7, C8, C9
Section 2. Control Proteins PID: Absent* Dysregulation: Absent/Low* Activation: Low/Unchanged Inhibition: Normalize	C1-INH	C1-INH	Factor H, FHR 1-5, Factor I
	C4BP + Factor I	MAP-1	Properdin
Section 3. Function Testing PID: Absent/Low Dysregulation: Low/Uncontrolled Activation: Decreased Inhibition: Low/Absent	Liposomal CP
	CH50 Hemolytic		AH50 Hemolytic	CH50 and AH50 Hemolytic
	ELISA CP	ELISA MP	ELISA AP	ELISA CP, MP, AP
Section 4. Autoantibodies PID: Normal/Absent Dysregulation: Present/Absent* Activation: Unchanged Inhibition: Unchanged	Anti-C1q, Anti-C1s, Anti-CI-INH	Anti-MBL, Anti-Ficolin-3	Anti-FH, Anti-FI, Anti-FB,
	C4Nef (Anti-C4bC2a)		C3Nef (Anti-C3bBb)	C5Nef (Anti-C3bBbC3b)
Section 5. Activation products PID: Absent Dysregulation: Increased Activation: Increased Inhibition: Normalize	C4a, C4b, C2a, C2b, C3a, C3b, iC3b, C3dg	C4a, C4b, C2a, C2b, C3a, C3b, iC3b, C3dg	Bb, Ba, C3a, C3b, iC3b, C3dg	C5a, C5b
				C5a, C5b C5b-9, sC5b-9

The analytes are separated by type. Presented with the type of analyte is the most common outcome of measurements divided into the four broad classes of complement disorders. *Outcome of measurements depends on the actual analyte that is deficient or dysregulated.

PID, Primary Immunodeficiency; CP, Classical pathway; AP, Alternative pathway; LP, Lectin pathway; MP, Microplate.