Test Details
Methodology
Radial immunodiffusion (RID)
Result Turnaround Time
7 - 11 days
Use
This test is intended for measuring human C1q in serum.
Special Instructions
State patient's sex on the request form.
Specimen Requirements
References
Calatroni M, Moroni G, Conte E, Stella M, Reggiani F, Ponticelli M. Anti-C1q antibodies: a biomarker for diagnosis and management of lupus nephritis. A narrative review. Front Immunol. 2024 June 13;15:1410032. PubMed 38938561
McMurray JC, Schornack BJ, Weskamp AL, et al. Immunodeficiency: Complement disorders. Allergy Asthma Proc. 2024 Sep 1;45(5):305-309. PubMed 39294906
Son M, Diamond B, Santiago-Schwarz F. Fundamental role of C1q in autoimmunity and inflammation. Immunol Res. 2015 Dec;63(1-3)101-106. PubMed 26410546
Thielens NM, Tedesco F, Bohlson SS, Gaboriaud C, Tenner AJ. C1q: A fresh look upon an old molecule. Mol Immunol. 2017 Sep;89:73-83. PubMed 28601358
van de Bovenkamp FS, Dijkstra DJ, van Kooten C, Gelderman KA, Trouw LA. Circulating C1q levels in health and disease, more than just a biomarker. Mol Immunol. 2021 Dec;140:206-216. PubMed 34735869
Custom Additional Information
The complement component 1q (or simply C1q) is a protein complex involved in the complement system, which is part of the innate immune system. C1q together with C1r and C1s form the C1 complex.1
Specimen
Serum
Volume
1 mL
Minimum Volume
0.1 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
Causes for Rejection
Chylous or lipemic serum; hemolysis; gross bacterial contamination. Plasma should be avoided since fibrin may result in the appearance of nonspecific precipitation, which may adversely affect interpretation.
Collection Instructions
Separate serum from cells.
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | 14 days |
| Refrigerated | 14 days |
| Frozen | 14 days |
| Freeze/thaw cycles | Stable x3 |
Reference Range
See table.
| Age | Male (mg/dL) | Female (mg/dL) |
|---|---|---|
| 0 to 1 y | Not established | Not established |
| 2 to 5 y | 9.8-18.5 | 9.7-19.1 |
| 6 to 17 y | 10.2-19.6 | 10.2-19.4 |
| >17 y | 10.2-20.3 | 10.3-20.5 |
Footnotes
1. Coss SL, Zhou D, Chua GT, et al. The complement system and human autoimmune disease. J Autoimmun. 2023 May;137:102979. PubMed 36535812
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 016824 | Complement C1q, Quantitative | 4478-4 | 016824 | Complement C1q, Quantitative | mg/dL | 4478-4 |
| Order Code | 016824 | |||||
| Order Code Name | Complement C1q, Quantitative | |||||
| Order Loinc | 4478-4 | |||||
| Result Code | 016824 | |||||
| Result Code Name | Complement C1q, Quantitative | |||||
| UofM | mg/dL | |||||
| Result LOINC | 4478-4 |