HAE / angioedema complement profile interpreter

Interprets the C4, C1-INH antigen, C1-INH function (and C1q) pattern to distinguish HAE type I/II, acquired C1-INH deficiency, and non-C1-INH angioedema.

Evidence tier: Guideline-derived.

Formula / logic

HAE type I: low C4, low C1-INH antigen, low C1-INH function, normal C1q. HAE type II: low C4, normal/high C1-INH antigen, low C1-INH function, normal C1q. Acquired C1-INH deficiency (AAE): low C1-INH function with low C1q. HAE with normal C1-INH: normal C4 and C1-INH, requires genetic testing (e.g. F12, PLG, KNG1).

Interpretation

C4 is a useful screen (typically low in C1-INH-dependent HAE between and during attacks) but C1-INH antigen + function are needed to type the disease. C1q separates acquired from hereditary deficiency.

Evidence & citations

  1. Maurer M, Magerl M, Betschel S, et al. The international WAO/EAACI guideline for the management of hereditary angioedema, the 2021 revision and update. Allergy. 2022;77(7):1961-1990. PMID 35006617

Clinician decision support. Verify against the cited source. Not a substitute for clinical judgment. 100% on-device; no patient data is stored or transmitted.