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Complement C1 esterase inhibitor

Immunology

Sample and container requirements

Serum

Minimum volume required

4 ml Blood

Special requirements

none

Patient preparation

None

Sample viability

Stable at 4 C for 8 days, If longer storage is anticipated then samples may be frozen prior to analysis

Turnaround time

7 days

Reference range

0.15-0.35g/L

Clinical guidance

Low levels of C1 inhibitor may indicate Hereditary Angioedma. These cases should be discussed with an immunologist for possible referral and further investigation. Normal levels of C1 inhibitor but having a clinical picture of C1 inhibitor deficiency should be investigated for functional C1 inhibitor defects. To allow correct interpretation of results concurrent complement C3 and C4 levels should be requested. https://labtestsonline.org.uk/tests/complement

Notes

Images to go here

This information was last updated on 19 August 2026