Useful in monitoring a wide range of inflammatory and autoimmune
disorders. Single point determinations are of limited value and
serial measurements are recommended.
Specimen transport: At room temperature
Repeat frequency: At significant change of
clinical symptoms, monitoring of treatment
Special precautions: None
Normal reference range: 0.14-0.39 g/L
Volume and sample type: 7ml clotted blood
Turnaround time (calendar days from sample
receipt to authorised result): Median - 1, 95th percentile - 5
Indications for the test: Pre-eclampsia,
hereditary angioedema, genetic deficiency, active SLE (associated
with low C3) sepsis (associated with low C3).
Factors affecting the test: Traumatic
venepuncture and delay in transport can lead to false negative
results due to in vitro activation.
Clinical workstation reference: C4
(Last updated October 7th