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HelpTest Code C1QFX C1q Complement, Functional, Serum
Reporting Name
C1Q Complement, Functional, SUseful For
Diagnosis of C1 deficiency
Investigation of a patient with an absent total complement level
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedOrdering Guidance
The total complement (CH50) assay (COM / Complement, Total, Serum) should be used as a screen for suspected complement deficiencies before ordering individual complement component assays. A deficiency of an individual component of the complement cascade will result in an undetectable CH50.
Specimen Required
Patient Preparation: Fasting preferred
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions:
1. Immediately after specimen collection, place the tube on wet ice.
2. Centrifuge and aliquot serum into plastic vial.
3. Immediately freeze specimen.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Frozen | 14 days |
Reference Values
34-63 U/mL
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
86161
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| C1QFX | C1Q Complement, Functional, S | 87722-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| C1QFX | C1Q Complement, Functional, S | 87722-5 |
Interpretation
Low levels of complement may be due to inherited deficiencies, acquired deficiencies, or due to complement consumption (eg, as a consequence of infectious or autoimmune processes).
The measurement of C1q activity is an indicator of the amount of C1 present. Absent C1q levels in the presence of normal C3 and C4 values are consistent with a C1 deficiency. Low C1q levels in the presence of low C4 but normal C3 may indicate the presence of an acquired inhibitor (autoantibody) to C1 esterase inhibitor.
Clinical Reference
1. Sonntag J, Brandenburg U, Polzehl D, et al: Complement systems in healthy term newborns: reference values in umbilical cord blood. Pediatr Dev Pathol. 1998 Mar-Apr;1(2):131-135
2. Prellner K, Sjoholm AG, Truedsson L: Concentrations of C1q, factor B, factor D and properdin in healthy children, and the age-related presence of circulating C1r-C1s complexes. Acta Paediatr Scand. 1987 Nov;76(6):939-943
3. Davis ML, Austin C, Messmer BL, et al: IFCC-standardization pediatric reference intervals for 10 serum proteins using the Beckman Array 360 system. Clin Biochem. 1996;29(5):489-492
4. Gaither TA, Frank MM: Complement. In: Henry JB, ed. Clinical Diagnosis and Management by Laboratory Methods. 17th ed. WB Saunders Company: 1984:879-892
5. O'Neil KM: Complement deficiency. Clin Rev Allergy Immunol. 2000;19:83-108
6. Frank MM: Complement deficiencies. Pediatr Clin North Am. 2000;47(6):1339-1354
8. Willrich MAV, Braun KMP, Moyer AM, Jeffrey DH, Frazer-Abel A. Complement testing in the clinical laboratory. Crit Rev Clin Lab Sci. 2021 Nov;58(7):447-478. doi: 10.1080/10408363.2021.1907297
Report Available
1 to 3 daysMethod Name
Automated Liposome Lysis Assay