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C1q Antibodies


C1q Antibodies
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Reference Range:

Negative <15 U/ml
Positive >= 15 U/ml

Turnaround Time:

24 Working Days


Internal Test Code:- C1QA


Indication: Hypocomplementaemic Urticarial Vasculitis (HUV), Systemic Lupus Eyrthematosus (SLE) and Lupus Nephiritis

Background: Anti-C1q antibodies are used in the diagnosis of Hypocomplementaemic Urticarial Vasculitis (HUV). They are also found in patients with SLE and, in particular, are markers of renal involvement in SLE. Patients with SLE often develop glomerulonephritis commonly referred to as lupus nephritis. Patients without C1q antibodies have a very low risk of developing an active lupus nephritis. In contrast, high titres of C1q autoantibodies indicate a high risk in developing an active lupus nephritis, particularly if they have previously suffered from lupus nephritis. Successful treatment of active lupus nephritis typically decreases C1q autoantibody titres. C1q autoantibodies are thought to play a pathogenic role in glomerular damage.

Method: Enzyme Linked Immunosorbent Assay (ELISA)

Repeat Frequency: As clinically indicated.



Vessels and Containers:

Serum gold-top

Sample Requirements:

500µl serum


Lipaemic, haemolytic and icteric samples should not be used.

How result is reported:

Numeric in U/ml

Important Information:

Entry Last Modified 22/05/2019


Anti-C1q antibodies

Reference Lab Description:

Protein Reference Unit, Northern General Hospital (Sheffield)

Transportation and Handling:

At room temperature

Special Precautions:


Time limits for requesting additional examinations:

Sample available in this laboratory for approximately 2 weeks. Test can only be added to samples already received by Immunology