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Test Code Billings Clinic: 4089 C3 (Third Component of Complement), Serum

Performing Laboratory

Billings Clinic Laboratory: Chemistry

Useful For

  • Assessing disease activity in systemic lupus erythematosus (SLE)
  • Investigating an undetectable total complement (CH50) level



Specimen Requirements

Serum should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.



  • Draw blood in a plain, red-top tube(s) or a serum gel tube(s).
  • Spin down and send 1.0 mL of serum frozen



Specimen Type Temperature Time
Serum Refrigerated 3 days
  Frozen (preferred) 3 weeks


Reject Due To

  • Specimens received outside of the required storage and stability requirements

Reference Values

90-180 mg/dL

Day(s) Test Set Up


Test Classification and CPT Coding

86160 - Complement; antigen, each component

LOINC Code Information

Reporting Name LOINC Code
Comp, C3 4485-9