Ordering Recommendation

Use to detect circulating immune complexes. Consider ordering Circulating Immune Complex Panel (3004430), which contains both Circulating Immune Complex, C3 Fragments and Circulating Immune Complex, C1q Binding assays.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Plain red or serum separator tube (SST).

Specimen Preparation

Allow complete clotting of red blood cells (up to 1 hour), then separate serum from cells within 30 minutes and freeze immediately. Transport 1 mL serum. (Min: 0.5 mL) If ordered in conjunction with a C1q Binding Assay, transfer TWO (2) 1 mL aliquots of serum to individual ARUP Standard Transport Tubes.

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Non-frozen specimens. Specimens exposed to repeated freeze/thaw cycles. Grossly hemolyzed, lipemic, and icteric specimens.


Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 20 days


Semi-Quantitative Enzyme-Linked Immunosorbent Assay


Mon, Thu, Sat


2-9 days

Reference Interval

Less than or equal to 15 µg Eq/mL

Interpretive Data

Many autoimmune disorders, chronic infections, and malignancies are associated with circulating immune complexes. Quantitation of immune complexes assists in staging immunologic disorders. Detection of circulating immune complexes is not essential to any specific diagnosis. Circulating immune complexes may be found without any evident pathology and positive results do not necessarily implicate immune complex-related disease process. Values between 15 and 20 ug Eq/mL are considered equivocal for the Circulating Immune Complex, C3 fragments assay. Repeat testing using a new specimen is recommended, if clinically indicated

Compliance Category



Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
3004432 Circulating Immune Complex, C3 fragments 5228-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Immune Complex Assay
Circulating Immune Complex, C3 fragments