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HelpTest ID C6FX C6 Complement, Functional, Serum
Useful For
Diagnosis of C6 deficiency
Investigation of a patient with an undetectable total complement (CH50) level
Method Name
Automated Liposome Lysis Assay
Reporting Name
C6 Complement, Functional, SSpecimen Type
Serum RedCollection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Immediately after drawing the specimen, place the tube on wet ice.
2. Spin down and separate serum from clot.
3. Immediately freeze specimen.
Additional Information: Fasting preferred.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum Red | Frozen | 14 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).
Patients with deficiencies of the late complement proteins (C5, C6, C7, C8, and C9) are unable to form the MAC, and may have increased susceptibility to neisserial infections.
A number of patients with C6 deficiency have been reported, and the majority of these patients are South African. Most of these patients have systemic meningococcal infection and some have had invasive gonococcal infections. Normal levels of C6 antigen have been reported in patients with dysfunctional C6 lytic activity.
Reference Values
32-57 U/mL
Cautions
The total complement (CH50) 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.
Absent (or low) C6 functional levels in the presence of normal C6 antigen levels should be replicated with a new serum specimen to confirm that C6 inactivation did not occur during shipping.
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
86161