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Test ID: COM Complement, Total, Serum

Reporting Name

Complement, Total, S

Useful For

Detection of individuals with an ongoing immune process

 

First-order screening test for congenital complement deficiencies

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 (or mannan-binding protein) 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, C2, C3, 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 generate the peptides that are necessary to clear immune complexes and to attract neutrophils 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.

 

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.

 

Undetectable complement levels are found in patients with specific component deficiencies. Decreased complement levels are found in infectious and autoimmune diseases due to fixation and consumption of complement.

Interpretation

Low levels of total complement (total hemolytic complement CH50) may occur during infections, disease exacerbation in patients with systemic lupus erythematosus, and in patients with immune complex diseases such as glomerulonephritis.

 

Undetectable levels suggest the possibility of a complement component deficiency. Individual complement component assays are useful to identify the specific deficiency.

Analytic Time

1 day

Day(s) and Time(s) Performed

Monday through Friday; 3 p.m.

Clinical Reference

1. Ross SC, Densen P: Complement deficiency states and infection: epidemiology, pathogenesis and consequences of neisserial and other infections in an immune deficiency. Medicine 1984;63:243-273

2. Frank MM: Complement in the pathophysiology of human disease. N Engl J Med 1987;316:1525-1530

3. Yamamoto S, Kubotsu K, Kida M, et al: Automated homogeneous liposome-based assay system for total complement activity. Clin Chem 1995;41:586-590

Method Name

Automated Liposome Lysis Assay

Specimen Type

Serum Red


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 28 days

Reference Values

≥16 years: 30-75 U/mL

Reference values have not been established for patients that are <16 years of age.

Test Classification

This test has been cleared or approved by the U.S. 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.

CPT Code Information

86162

LOINC Code Information

Test ID Test Order Name Order LOINC Value
COM Complement, Total, S 4532-8

 

Result ID Test Result Name Result LOINC Value
COM Complement, Total, S 4532-8
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Neuroimmunology, mml-Neuromuscular, mml-Autonomic, mml-Pediatric