C1 Inhibitor Functional

Test/Investigation

C1 Inhibitor Functional

Site(s) or Laboratory offering Test/Investigation

Referral laboratory

Units

U/mL

Also Known as/Frequency of Test

C1 Inhibitor Functional

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

EDTA

Turnaround times (TAT) Urgent/Routine/GP or OPD

2 weeks

Reference intervals (adult unless stated)

46 – 130 U/mL