Complement (C3 & C4)

Description: 
The measurement of C3 and C4 aids in diagnosing the underlying cause of recurrent microbial infections or inflammation. It may be used to help diagnose and monitor the activity of acute or chronic autoimmune diseases such as systemic lupus erythematosus (SLE).

Clinical details: 
Complement components are fairly rapidly synthesized (or released into the circulation) following trauma or inflammation and elevated concentrations are common in many acute illnesses. In certain diseases, with more generalised or prolonged consumption, low concentrations do occur and are clinically useful in diagnosis, and in monitoring progress. Clinical use include: renal disease, joint disease, and multisystem disorders with evidence of vasculitis, since low concentrations would imply an immunological basis for the symptoms.
Reference range: 

See Chemistry Reference Ranges Document at Automated Chemistry Laboratory at Guy's and St Thomas'

Units: 
g/L
Sample type and Volume required: 
Clotted (yellow SST tube) Serum or EDTA (purple top) Plasma.
Turnaround time: 
2 days
Contacts:
Blood Sciences Department-Guy's And St Thomas' Hospital
St Thomas' Hospital
North Wing - 5th Floor
Westminster Bridge Road
London SE1 7EH
Contact: 020 7188 9247

Guy's Hospital
Southwark Wing - 4th Floor
Great Maze Pond
London SE1 9RT
Contact: 020 7188 4781
Automated Chemistry Laboratory at Guy's and St Thomas' Clinical Advisory Service
Monday – Friday, 09:00-17:00 h: 07738897061
Out of hours, weekends & bank holidays: find details on Rotawatch on Trust intranet GTi, or contact via GSTT switchboard.
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 29/12/2023