Test Overview
Test Methodology

Enzyme Immunoassay

Test Usage

Follow lupus patient's response to therapy; screen for genetic complement component deficiency. Detection of deficiencies and decreased levels of serum complement as seen in renal disease (acute glomerulonephritis, membranoproliferative glomerulonephritis, renal allograft rejection), collagen disease (active systemic lupus erythematosus (SLE), 10% of patients with rheumatoid arthritis (RA), hemolytic anemia (paroxysmal cold hemoglobinuria), hypersensitivity and autoimmune diseases (acute serum sickness, acute vasculitis) as well as subacute bacterial endocarditis, mixed cryoglobulinemia, and advanced hepatic cirrhosis.

Reference Range *

41 - 95 U/mL

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

Levels are affected by patient's age, stage and activity of disease, treatment and genetic factors. A single normal result may be misleading; longitudinal studies are clinically more helpful.

Test Details
Days Set Up
Monday, Thursday
Analytic Time

8 hours

Soft Order Code
CH50
MiChart Code
Complement, Total (CH50)
Synonyms
  • CAE Total Complement
  • CH50
  • Functional Complement Assay
  • Total Active Complement
  • Total Hemolytic Complement
  • CAE TOTAL COMPLEMENT (CH50)
Laboratory
Chemical Pathology
Section
Immunopathology
Specimen Requirements
Collection Instructions

MLAB Collection: Collect specimen in a red top or SST tube. Allow the specimen to clot at room temperature for 30 to 60 minutes (65 minutes maximum). Centrifuge and aliquot serum into a plastic vial. Freeze immediately.

Special Handling

Place on ice immediately or process according to MLAB Collection below.

Rejection Criteria
Specimen remaining at room temperature more than 65 minutes, serum not separated from red cells within 60 minutes of collection, or serum aliquot refrigerated longer than 48 hours.
Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.2 mL serum
Additional Information

Measures biologically active and functional classical complement pathway and the presence of inhibitor activity as a whole. Complement mediates immune reactions. Hypocomplementemia that accompanies some forms of renal disease may indicate immune utilization. Low serum complement levels occur in some patients with severe RA, and may indicate the development of vasculitis. Low levels tend to correlate with active immunologic diseases. Total hemolytic complement, C3, and C4 may be decreased in a variety of diverse clinical situations, in particular in cases in which immune complex activation has occurred. Such problems include cases of SLE, especially if there is nephritis. Hypercomplementemia may be seen as part of the acute phase reaction.

Billing
CPT Code
86162
Fee Code
21911
LOINC
4532-8
Resources