Test/Investigation
C1 Inhibitor Level
Site(s) or Laboratory offering Test/Investigation
Referral laboratory
Units
g/L
Also Known as/Frequency of Test
C1EQ; C1 Esterase Inhibitor, C1 Esterase Antibodies
Indications
C1 esterase inhibitor deficiency is the most common complement deficiency resulting in hereditary angioedema. 85% of HAE results from a reduced level of the C1Inhibitor. Acquired C1 inhibitor deficiency may occur with B-cell lymphomas and some autoimmune diseases. Samples collected during an acute attack of angioedema due to C1 inhibitor deficiency are characterised by a low C4. A normal C4 level virtually excludes all forms of C1 inhibitor deficiency. Referred outside of EPA.
Comments/Precautions
Referred outside of EPA
Sample type
Serum
Turnaround times (TAT) Urgent/Routine/GP or OPD
2 weeks
Reference intervals (adult unless stated)
0.19 – 0.39 g/L