C4 is usually measured in investigation of patients with renal
disease, joint disease and multi-system disorders with evidence of
vasculitis; low concentrations imply an immunological basis for the
symptoms. C4 (and C3) levels may be useful in patients with
recurrent infections with normal or raised immunoglobulin levels,
since genetic and acquired defects sometimes present as
immunodeficiency (CH50 analysis also required in such cases).
Request on ICE
Investigation of genetic or acquired complement defects or if
agreed with Consultant Biochemist.
Causes for Rejection
Unlabelled or incorrectly labelled sample; not meeting specific
criteria for analysis.
0.14 - 0.54 g/L