DISCLAIMER: This link was displayed at 22:14:02 12/07/2025 and expires on 17/07/2025 if printed.

Go to http://testguide.adhb.govt.nz/EGuide/ for more information.

Specimen Collection

Samples stable at 2-8 ^o C for up to 48 hours. For longer storage samples must be frozen at -20 ^o C.

3.5 mL SST Serum (Preferred)
4 mL Plain Serum
Reference Intervals
Units: mg/L

Age Range	Male	Female
All	118 - 238	118 - 244

Abnormal

Age Range	Either Sex
All	33 - 209[1] 93 - 183[2]

[1] Active SLE
[2] Inactive SLE
Turnaround Time: Between 1 week and 2 weeks

Performed Weekly.

.

Assay Method

Radial Immunodiffusion using the Binding Site kit.

Diagnostic Use and Interpretation

C1q is a 400 kD hexameric gamma-2 protein that is a subunit of C1 ? the first component of complement.  The binding of two or more C1q?s six globular domains initiates the classical pathway of complement activation.  C1q binds readily to the CH2 domains of the aggregated IgG molecules in an immune complex or the CH3 domains of a single IgM molecule whose conformation has been altered following antigen binding.  It can also bind directly to certain micro-organisms and mycoplasmas.

The multivalent binding of C1q is believed to lead to a conformational change in the C1q complex, activating C1r then C1s and thereby initiating the classical complement pathway.  The collagen-like tail domain of C1q (which is only exposed once C1 inactivator dissociates C1r2 and C1s2 from the C1 activator complex) increases the phagocytosis of particles by monocytes and macrophages.  Serum levels of C1q are reduced in immune complex disease, systemic lupus erythematosus (SLE) and meningitis.  Heredity deficiency is also known.

 

References:

1. Mancini, G, Vaerman, J P et al.  (1964). Protides of the biological fluids (XI Colloquium).  Peters H.  (ed.), Amsterdam, Elsevier Publishing Co.,370-373.
2. Mancini, G, Carbonara, A O and Heremans, JF (1965).  Immunochemical quantitation of antigens by single radial immunodiffusion, Immunochem 2, 235-254.
3. Fahey, J L & McKelvey, E M (1965).  Quantitative determination of serum immunoglobulins in antibody-agar plates.  J.  Immunol., 94, 84-90.

Contact Information

The immunopathology team can be reached via email: immunology@adhb.govt.nz or via Lablink

• Immunology lab registrar
• Assoc. Prof. Rohan Ameratunga (Immunopathologist)
• Dr Maia Brewerton (Immunopathologist)

Specimen Transport Instructions for Referring Laboratories

Samples stable at 2-8 ^o C for up to 48 hours. For longer storage samples must be frozen and transported at -20 ^o C.

Last updated at 20:21:37 21/02/2025