C9 Function
Test Code
C9F
Description
The complement system is part of our innate immune response. It is vital to our defense against invasive microorganisms. Complement activation can occur through the classical, lectin and alternative pathway, which then converge to a common terminal pathway. Complement deficiency can lead to life-threatening infections as well as long-term autoimmune conditions such as systemic lupus erythematosus (SLE) and hereditary angioedema (HAE).
The C9 hemolytic assay is a sensitive method for detection of complement protein C9 activity or lack thereof. C9 is an essential component of the terminal pathway membrane attack complex (MAC). Severe or recurrent infections that produce strong activation of either complement pathway can lead to low C9 protein levels and reduced C9 activity. Low or absent C9 activity is also observed with genetic deficiencies of C9 that lead to a lack of or insufficient production of C9 protein. Low C9 activity can be associated with low CH50 and AH50 activity.
Collect
Serum from a Red top tube is the only acceptable sample type. The collection tube should be completely filled with blood. Invert tube several times to initiate the clotting process. Keep the tube filled with blood at room temperature for 30-60 minutes to allow the blood to clot.
Patient Prep
Centrifuge the collection tube at 1600 (± 200) x g (rcf) at 4°C (± 2°C) for 15 (±1) minutes. Transfer the cell-free serum to a clean cryogenic storage tube and immediately store the cryogenic tube at -60°C or below in an ultra-low freezer.
Preferred volume: 1.0 mL serum
Minimum volume: 0.25 mL serum
Pediatric Collection
Minimum volume: 0.25 mL serum
Unacceptable Conditions
Thawed samples or samples stored at room temperature prior to shipment.
Storage Transport Temp
Thawed samples or samples stored at room temperature prior to shipment.
Stability
-60°C or below in an ultra-low freezer - up to 2 years
Notes
Additional testing may be needed for less than perfect samples on confirmatory testing/reflex testing.
To prevent unnecessary delays in testing, please send one aliquot per test request.
Performed
Monday - Friday
Methodology
Hemolytic Assay
Turnaround Time
up to 4 weeks
Department
Complement Lab
Synonyms
Complement (C9 Function), Hemolytic Assay (C9 Function)
Study Offerings
Not offered
Reference Interval
8,310 - 42,320 Units/mL
CPT Code
86161
New York Approved
Legacy
FDA
LDT