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Test Code C5AG C5 Complement, Antigen, Serum

Reporting Name

C5 Complement, Antigen, S

Useful For

Diagnosis of C5 deficiency

 

Investigation of a patient with an absent total complement (CH50) level

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Ordering 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.



Specimen Required


Patient Preparation: Fasting preferred but not required

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and separate serum from clot.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 60 days
  Refrigerated  28 days
  Ambient  7 days

Reference Values

10.6-26.3 mg/dL

Day(s) Performed

Monday through Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86160

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C5AG C5 Complement, Antigen, S 4505-4

 

Result ID Test Result Name Result LOINC Value
C5AG C5 Complement, Antigen, S 4505-4

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 C5 levels in the presence of normal C3 and C4 values are consistent with a C5 deficiency. Absent C5 levels in the presence of low C3 and C4 values suggests complement consumption.

 

A small number of cases have been described in which the complement protein is present but is nonfunctional. These rare cases require a functional assay to detect the deficiency C5FX / C5 Complement, Functional, Serum).

Clinical Reference

1. Sonntag J, Brandenburg U, Polzehl D, et al: Complement systems in healthy term newborns: reference values in umbilical cord blood. Pediatr Dev Pathol 1998;1:131-135

2. Prellner K, Sjoholm AG, Truedsson L: Concentrations of C1q, factor B, factor D and properdin in healthy children, and the age-related presence of circulating C1r-C1s complexes. Acta Peidiatr Scand 1987;76:939-943

3. Davis ML, Austin C, Messmer BL, et al: IFCC-standardization pediatric reference intervals for 10 serum proteins using the Beckman Array 360 system. Clin Biochem 1996;29,5:489-492

4. Gaither TA, Frank MM: Complement. In Clinical Diagnosis and Management by Laboratory Methods. 17th edition. Edited by JB Henry. Philadelphia, WB Saunders Company, 1984, pp 879-892

5. O'Neil KM: Complement deficiency. Clin Rev Allergy Immunol 2000;19:83-108

6. Frank MM: Complement deficiencies. Pediatr Clin North Am 2000;47(6):1339-1354

Report Available

2 to 5 days

Method Name

Nephelometry