Potential tests for the positive diagnosis of complement-mediated HUS
| Available tests for the diagnosis of complement-mediated HUS . | Limitations . |
|---|---|
| Biomarkers of complement alternative pathway activation Low plasma C3 level/normal C4 level | Present in only 30% of cases of aHUS. Normal levels do not exclude the diagnosis of aHUS |
| Assessment of complement proteins plasma levels Factor H and factor I plasma levels | Low plasma levels provide evidence of complement dysregulation and of the pathogenicity of a potential rare variant identified in encoding gene. Nonspecific for aHUS |
| CD46 expression on neutrophils | Nonspecific decrease during the acute phase of several forms of TMA9 |
| Biomarkers of complement terminal pathway activation sC5b-9 plasma level | Overlap between several forms of TMA and healthy individuals |
| In vitro deposition of complement (C3c, C5b-9) at the surface of endothelial cells modified Ham test | Discrepant results between laboratories. Requires duplication and standardization19-21 |
| Available tests for the diagnosis of complement-mediated HUS . | Limitations . |
|---|---|
| Biomarkers of complement alternative pathway activation Low plasma C3 level/normal C4 level | Present in only 30% of cases of aHUS. Normal levels do not exclude the diagnosis of aHUS |
| Assessment of complement proteins plasma levels Factor H and factor I plasma levels | Low plasma levels provide evidence of complement dysregulation and of the pathogenicity of a potential rare variant identified in encoding gene. Nonspecific for aHUS |
| CD46 expression on neutrophils | Nonspecific decrease during the acute phase of several forms of TMA9 |
| Biomarkers of complement terminal pathway activation sC5b-9 plasma level | Overlap between several forms of TMA and healthy individuals |
| In vitro deposition of complement (C3c, C5b-9) at the surface of endothelial cells modified Ham test | Discrepant results between laboratories. Requires duplication and standardization19-21 |
These tests have not yet been fully validated and replicated, and their clinical relevance remains uncertain.