C1-Esterase Inhibitor

Pathology category

Immunology

Code

C1E

Referral code

RHH

Request form

Test information

Antigenic and functional levels. Typically C1-Esterase Inhibitor deficiency, both hereditary and acquired, is associated with low C4 levels during acute episodes, which is therefore used as a screening test for suspected HAE or AAE – see below.Hereditary Angioedema (HAE) – Autosomal dominant disorder commonly due to C1INH deficiency. Most cases have reduced serum C1 INH levels (Type 1). One in ten cases may have normal C1 INH levels, but reduced function (Type 2).Aquired Angioedema (AAE) – Reduced C1 INH levels, most commonly associated with B-cell lymphoproliferative disorders.

Guidelines

Pre-analytical

Reference range

Tube type

Tube type info

SST, Plain or Lithium Heparin

Special requirements

Serum

Minimum volume

Assay frequency

Weekly

TAT Inpatient (urgent)

TAT Inpatient

TAT GP/Outpatient

up to 2 weeks

Referral lab

Immunology Russells Hall Hospital