Home
HelpTEST ID C1Q Complement C1q, Serum
Reporting Name
Complement C1q, SSpecimen Type
SerumSpecimen Required
Patient Preparation:
Fasting: 12 hours, preferred but not required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 28 days |
| Frozen | 28 days | |
| Ambient | 21 days |
Method Name
Nephelometry
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
Reference Values
12-22 mg/dL
Day(s) Performed
Monday through Friday
Report Available
2 to 5 daysSpecimen Retention Time
14 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
86160
Useful For
Assessment of an undetectable total complement level
Diagnosing congenital C1 (first component of complement) deficiency
Diagnosing acquired deficiency of C1 inhibitor
Clinical Information
The first component of complement (C1) is composed of 3 subunits designated as C1q, C1r, and C1s. C1q recognizes and binds to immunoglobulin complexed to antigen and initiates the complement cascade. Congenital deficiencies of any of the early complement components (C1, C2, C4) results in an inability to clear immune complexes. Inherited deficiency of C1 is rare.
Like the more common C2 deficiency, C1 deficiency is associated with increased incidence of immune complex disease (systemic lupus erythematosus, polymyositis, glomerulonephritis, and Henoch-Schonlein purpura). Low C1 levels have also been reported in patients with abnormal immunoglobulin levels (Bruton and common variable hypogammaglobulinemia and severe combined immunodeficiency). This is most likely due to increased catabolism.
The measurement of C1q is an indicator of the amount of C1 present.