Complement C3 and C4 Test


The complement system is an integral part of innate and acquired immunity. There are 3 pathways- the classical, lectin and alternative pathway. The complement component C3 is a key protein in all reaction pathways, while the component C4 is part of the classical and lectin pathway. Activation of the complement cascade can result in consumption of C3 and / or C4, and therefore a reduction in their concentration. We routinely test complement C3 and C4 levels.





Functional Antibody Test


Immunology Laboratory

Specimen Type:



If samples have to be stored prior to dispatch, please keep at 4°C

Posting Details:

Room temperature

Posting Address:

Department of Immunology, City Hospital, Dudley Road, Birmingham, B18 7QH

Clinical Use:

C3 /C4 levels are useful in monitoring conditions associated with immune complexes e.g. SLE,systemic vasculitis


Approximately 24 hours

External QA Scheme:

UK NEQAS, C1 inhibitor and functional complement

CPA Accredited Lab/Test:

Full accreditation

Key Contact:

Shabir Rajpar


Tel: 0121 507 4258

Clinical Lead for this assay:

Dr Sadia Noorani

Tel: 0121 507 5157






  SWBH NHS Trust 2018