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HelpTest ID C5AG C5 Complement, Antigen, Serum
Useful For
Diagnosis of C5 deficiency
Investigation of a patient with an absent total complement (CH50) level
Method Name
Nephelometry
Reporting Name
C5 Complement, Antigen, SSpecimen Type
SerumCollection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
1. Fasting
2. Spin down and separate serum from clot.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Frozen (preferred) | 60 days |
| Ambient | 7 days | |
| Refrigerated | 7 days |
Clinical Information
Complement proteins are components of the innate immune system. There are 3 pathways to complement activation:1) the classic pathway, 2) the alternative (or properdin) pathway, and 3) the lectin activation (mannan-binding protein, [MBP]) pathway. The classic pathway of the complement system is composed of a series of proteins that are activated in response to the presence of immune complexes. The activation process results in the generation of peptides that are chemotactic for neutrophils and that bind to immune complexes and complement receptors. The end result of the complement activation cascade is the formation of the lytic membrane attack complex (MAC).
The absence of early components (C1-C4) of the complement cascade results in the inability of immune complexes to activate the cascade. Patients with deficiencies of the early complement proteins are unable to clear immune complexes or to generate lytic activity. These patients have increased susceptibility to infections with encapsulated microorganisms. They may also have symptoms that suggest autoimmune disease and complement deficiency may be an etiologic factor in the development of autoimmune disease.
More than 30 cases of C5 deficiency have been reported. Most of these patients have neisserial infections.
Reference Values
10.6-26.3 mg/dL
Cautions
The total complement assay (COM / Complement, Total, Serum) should be used as a screen for suspected complement deficiencies before ordering individual complement component assays. A deficiency of an individual component of the complement cascade will result in an undetectable total complement level.
Day(s) Performed
Monday through Saturday; Continuous with a 3 p.m. cutoff
Report Available
Same day/1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
86160