Investigating an undetectable total complement (CH50)
Confirming hereditary angioedema (with low C1 inhibitor)
Assessing disease activity in systemic lupus erythematosus, proliferative glomerulonephritis, rheumatoid arthritis, and autoimmune hemolytic anemia
Nephelometry
C4 (4th Component of Complement), Serum
C4 (Fourth Component of Complement), Serum
C4 Complement Serum
C4, Serum
Complement C4, Serum
Fourth Component of Complement
Hereditary Angioedema Panel (3 tests)
Serum
Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Specimen Volume: 1 mL
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
0.5 mL
Gross hemolysis | OK |
Gross lipemia | Reject |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 7 days | |
Frozen | 28 days | ||
Ambient | 72 hours |
Investigating an undetectable total complement (CH50)
Confirming hereditary angioedema (with low C1 inhibitor)
Assessing disease activity in systemic lupus erythematosus, proliferative glomerulonephritis, rheumatoid arthritis, and autoimmune hemolytic anemia
The complement system is an integral part of the immune defenses. It can be activated via immune complexes (classic pathway) or by bacterial polysaccharides (alternative pathway). The classic complement pathway consists of recognition, (C1q, C1r, C1s), activation (C2, C3, C4), and attack (C5, C6, C7, C8, C9) mechanisms with respect to their role in antibody-mediated cytolysis. C4 is one of the activation proteins of the classic pathway.
In the absence of C4, immune complexes will not be cleared by C3 activation peptides, but bacterial infections can still be defended via the alternative pathway.
C4 may be decreased in systemic lupus erythematosus, early glomerulonephritis, immune complex disease, cryoglobulinemia, hereditary angioedema, and congenital C4 deficiency.
14-40 mg/dL
C4 levels will be decreased in acquired autoimmune disorders, in active phase of lupus erythematosus, and in rheumatoid arthritis
An undetectable C4 level (with normal C3) suggests a congenital C4 deficiency
Levels will be increased in patients with autoimmune hemolytic anemia
The results are dependent on appropriate specimen transport.
1. Ross SC, Densen P: Complement deficiency states and infection:
2. Frank MM: Complement in the pathophysiology of human disease. N Engl
3. Tiffany TO: Fluorometry, nephelometry, and turbidimetry. In Textbook of
Nephelometry.(Instruction manual: Siemens Nephelometer II Operations. Siemens, Inc., Newark, DE)
Monday through Friday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
86160
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
C4 | Complement C4, S | 4498-2 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
C4 | Complement C4, S | 4498-2 |