In any disease state where complement consumption is considered to be taking place, even if the C3 concentration is normal. In SLE and rheumatoid arthritis this can be a sensitive monitor of clinical activity.
In patients with low concentrations of complement components, or very low CH50, this test can indicate the likelihood of active consumption as the cause of the hypocomplementaemia.
Sample requirement: 2 mL serum.
Reference range: Normal values are less than 150 mg/L
Centres offering this assay:
London St George’s Hospital PRU Diagnostic Service
Sheffield Northern General’s PRU Diagnostic Service