PRINCIPLE OF THE METHOD
Anti-human C4 antibodies when mixed with samples containing C4, form
insoluble complexes. These complexes cause an absorbance change,
dependent upon the C4 concentration of the patient sample, that can be
quantified by comparison from a calibrator of know C4 concentration.
CLINICAL SIGNIFICANCE1
C4 is the second component reacting in the classical pathway cascade. Most
synthesis occurs in the hepatic parenchymal cells, although some may be
synthesized by monocytes or others tissues.
C4 levels in plasma rise modestly after trauma or inflammation and tissue
necrosis (acute phase process).
Inherited primary deficiency of C4 is associated with a high prevalence of
autoimmune or collagen vascular disease, particularly Systemic Lupus
Erythematosus (SLE). Also, levels of C4 are more commonly depressed
because of consumption as a consequence of formed immune-complexes.
STORAGE AND STABILITY
All the components of the kit are stable until the expiration date on the label
when stored tightly closed at 2-8ºC and contaminations are prevented during
their use. Do not use reagents over the expiration date.
Reagent deterioration: The presence of particles and turbidity. Do not use.
Do not freeze; frozen Antibody or Diluent could change the funcitionality of the
test.
ADDITIONAL EQUIPMENT
- SPIN 800 autoanalyzer.
- Laboratory equipment.
SAMPLES
Fresh serum or plasma. EDTA or heparin should be used as anticoagulant.
Stable 7 days at 2-8ºC or 3 months at –20ºC.
The samples with presence of fibrin should be centrifuged.
Do not use highly hemolized or lipemic samples.
REFERENCE VALUES5
Neonates: Between 13 - 38 mg/dL.
Adults: Between 10 – 40 mg/dL.
Each laboratory should establish its own reference range.
QUALITY CONTROL
Control sera are recommended to monitor the performance of manual and
automated assay procedures. Spinreact PROT CONTROL (Cod.:1102004).
Each laboratory should establish its own Quality Control scheme and corrective
actions if controls do not meet the acceptable tolerances.
