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Test Code C1Q Complement C1q, Serum

Reporting Name

Complement C1q, S

Useful For

Assessment of an undetectable total complement level

 

Diagnosing congenital C1 (first component of complement) deficiency

 

Diagnosing acquired deficiency of C1 inhibitor

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Patient Preparation: Fasting for 12 hours

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  21 days

Reference Values

12-22 mg/dL

Day(s) Performed

Monday through Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86160

LOINC Code Information

Test ID Test Order Name Order LOINC Value
C1Q Complement C1q, S 4478-4

 

Result ID Test Result Name Result LOINC Value
C1Q Complement C1q, S 4478-4

Interpretation

An undetectable C1q in the presence of an absent total complement and normal C2, C3, and C4 suggests a congenital C1 (first component of complement) deficiency.

 

A low C1q in combination with a low C1 inhibitor and low C4 suggests an acquired C1 inhibitor deficiency.

Clinical Reference

1. Stegert M, Bock M, Trendelenburg M. Clinical presentation of human C1q deficiency: How much of a lupus? Mol Immunol. 2015;67(1):3-11

2. Tangye SG, Al-Herz W, Bousfiha A, et al. Human inborn errors of immunity: 2022 update on the classification from the International Union of Immunological Societies Expert Committee. J Clin Immunol. 2022;42(7):1473-1507

3. Beurskens FJ, van Schaarenburg RA, Trouw LA. C1q, antibodies and anti-C1q autoantibodies. Mol Immunol. 2015;68(1):6-13

Report Available

2 to 5 days

Method Name

Nephelometry