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HelpTest Code C5FX C5 Complement, Functional, Serum
Reporting Name
C5 Complement, Functional, SUseful For
Diagnosis of C5 deficiency
Investigation of a patient with an undetectable total complement (CH50) level
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedAdvisory Information
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.
Specimen Required
Patient Preparation: Fasting preferred
Supplies: Aliquot Tube, 5 mL (T465)
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Immediately after specimen collection, place the tube on wet ice.
2. Centrifuge and aliquot serum into plastic vial.
3. Immediately freeze specimen.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen | 14 days |
Reference Values
29-53 U/mL
Day(s) and Time(s) Performed
Monday through Friday; 3 p.m.
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
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| C5FX | C5 Complement, Functional, S | 60472-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| C5FX | C5 Complement, Functional, S | 60472-8 |
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. More than 30 cases of C5 deficiency have been reported. Most of these patients have neisserial infections.
Complement levels can be detected by antigen assays that quantitate the amount of the protein (C5AG / C5 Complement, Antigen, Serum). For most of the complement proteins, a small number of cases have been described in which the protein is present but is nonfunctional. These rare cases require a functional assay to detect the deficiency.
Analytic Time
Same day/1 dayReject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
NY State Approved
YesMethod Name
Automated Liposome Lysis Assay