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HelpTest Code C2FXN C2 Complement, Functional, Serum
Reporting Name
C2 Complement, Functional, S, NRUseful For
Investigation of a patient with a low (absent) hemolytic complement
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedOrdering Guidance
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.
To evaluate for complement C2, C3, and C4 in one orderable, consider ordering C2 / C2 Complement, Functional, with Reflex, Serum.
Specimen Required
Patient Preparation: Fasting preferred but not required
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
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 | 21 days |
Reference Values
25-47 U/mL
Day(s) Performed
Monday through Friday
CPT Code Information
86161
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| C2FXN | C2 Complement, Functional, S, NR | 93977-7 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| C2FX | C2 Complement,Functional,S | 93977-7 |
| INT53 | Interpretation | 69048-7 |
Interpretation
Low levels of complement may be due to inherited deficiencies, acquired deficiencies, or due to complement consumption (eg, as a consequence of infectious or autoimmune processes).
Absent (or low) C2 levels in the presence of normal C3 and C4 values are consistent with a C2 deficiency.
Low C2 levels in the presence of low C3 and C4 values are consistent with a complement-consumptive process.
Low C2 and C4 values, in the presence of normal values for C3 is suggestive of C1 esterase inhibitor deficiency.
Report Available
1 to 3 daysReject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
Method Name
Automated Liposome Lysis Assay