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Comment |
| Measurement of serum C3 and C4 |
Low C3 with normal C4 indicates alternative pathway activation |
| Measurement of C3 nephritic factor |
C3 nephritic factors are associated with C3 glomerulopathy; their correlation with disease course is unclear |
| Measurement of serum factor H |
Factor H deficiency is associated with C3 glomerulopathy and is invariably associated with reduction in serum C3 |
| Serum paraprotein detection |
Paraproteinemia associated with C3 glomerulopathy, specialist tests required to determine whether paraprotein is a cause of uncontrolled C3 activation |
| Screening for CFHR5 mutation |
CFHR5 nephropathy is a well-characterized cause of C3 glomerulopathy,3, 21 and thus screening for this mutation is clinically informative |
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| Tests that should be considered on a case-by-case basis as they require expert interpretation and/or clinical validation |
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Comment |
| Measurement of serum factor B |
Uncontrolled alternative pathway activation may be associated with reduced factor B levels |
| Measurement of serum C5 |
May be reduced in terminal pathway activation and could indicate group most likely to benefit from therapeutic C5 inhibition |
| Measurement of markers of C3 activation, e.g., C3d, C3c, C3adesArg |
Activated C3 components are more sensitive markers of C3 activation than antigenic levels of intact C3 |
| Measurement of markers of C5 activation, e.g., C5adesArg, soluble C5b-9 |
Activated C5 components are more sensitive markers of C5 activation than antigenic levels of intact C5 |
| Measurement of anti-factor H autoantibodies |
Anti-factor H autoantibodies are associated with C3 glomerulopathy; correlation with disease course is unclear; especially important to measure in patients with low C3 and negative C3 nephritic factor |
| Anti-factor B autoantibodies |
Anti-factor B autoantibodies are associated with C3 glomerulopathy; correlation with disease course is unclear |
| Mutation screening of complement regulatory genes (e.g., CFH, CFI, CD46), activation protein genes (C3, CFB) and assessment of copy number variation across the CFH-CFHR locus |
Mutations in these genes associated with C3 glomerulopathy; especially important to screen for CFH mutations in patients with low C3 and negative C3 nephritic factor |
