Lab Test

Total Complement (CH50)

CH50, Complement CH50, Total

Test Codes

Antrim #30240, EPIC: LAB7024, SOFT: CH50G

Specimen Collection Criteria

Collect: One plain Red-top tube. (Minimum Whole Blood: 2.0 mL)

Critical Frozen. Document the collection time on either the tube or requisition form and send specimen immediately for processing. 

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes at room temperature (20-26°C or 68-78.8°F) then immediately centrifuge to separate serum from cells. Transfer serum to a plastic transport tube and freeze (-20°C/-4°F or below) immediately. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: Serum in a plastic transport tube, frozen (-20°C/-4°F or below). (Minimum Serum: 0.5 mL)

Rejection Criteria

  • Specimens collected in any tube other than a plain Red-top tube.
  • Specimens not collected and processed as indicated.
  • Specimens not received frozen from off-site areas/offices.
  • Severely hemolyzed, lipemic or icteric specimens.

In-Lab Processing

Let specimen clot 30-60 minutes at room temperature (20-26°C or 68-78.8°F) then immediately centrifuge to separate serum from cells. Freeze (-20°C/-4°F or below) immediately. (Minimum Serum: 0.5 mL)


Specimen Stability for Testing:

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): 14 days

Specimen Storage in Department Prior to Disposal:

Frozen (-20°C/-4°F or below): 7 days


Royal Oak Special Chemistry Laboratory


Tuesday, Thursday.
Results available within 3 business days.

Reference Range

Greater than or equal to 41.7 U/mL.

Test Methodology

Liposome Immunoassay (The Binding Site SPAPLUS Analyzer)

Clinical Utility

Total Complement (CH50) is a functional assay that measures the activity of complement components C1 to C9 (i.e., the classical and terminal pathways). It does not measure the functional activity of the alternative pathway. If the Total Complement (CH50) measurement is zero or very low it is advisable to repeat the test to confirm the result. If the result is confirmed, the clinical presentation should be considered prior to further testing. If the patient exhibits recurrent neisserial infection, immunochemical determination of C5, C6, C7 and C8 is advised (or a functional assay for C5-C8). If the clinical problem is angioedema, initial studies should include C3, C4, C1 inhibitor (and possibly C1q and C2). Acquired disorders such as immune-mediated glomerulonephritis and other autoimmune disorders should direct testing towards C3 and C4.

Note: In order to assess the alternative complement pathway, the alternative pathway CH50 may be ordered (send-out test).

CPT Codes

LOINC: 4532-8


Last Updated


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