Ordering Recommendation

Aids in the diagnosis of C1q deficiency. For testing to detect circulating immune complexes, refer to Circulating Immune Complex, C1q Binding (0050301).

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation

Lavender (EDTA) or pink (K2EDTA).

Specimen Preparation

Separate plasma from cells ASAP or within 2 hours of collection. Transfer 1 mL plasma to an ARUP Standard Transport Tube and freeze immediately. (Min: 0.1 mL)

Storage/Transport Temperature

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

Unacceptable Conditions

Grossly hemolyzed, hyperlipemic, or room temperature specimens. Serum or non-EDTA plasma.


Ambient: Unacceptable; Refrigerated: 48 hours; Frozen: 1 month


Radial Immunodiffusion


Tue, Fri


5-10 days

Reference Interval

109-242 µg/mL

Interpretive Data

Compliance Category



For the C1q Binding assay, refer to ARUP test code 0050301. The C1q Binding assay detects circulating immune complexes. The Complement Component 1q Level assay quantifies the active fraction component, C1q, of the C1 complement protein complex.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0099130 Complement Component 1q Level 4478-4
* 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.


  • C1
  • C1 esterase inhibitor
  • C1q
  • C1q Level
  • Complement Component C1q
  • First Component of Complement
  • Total Complement
  • Total Hemolytic Complement Activity
Complement Component 1Q Level