Shortened Activated Partial Thromboplastin Time May Help in Diagnosing Hereditary and Acquired Angioedema

Objective: To evaluate whether activated partial thromboplastin time (APTT) could be used in the laboratory diagnosis of hereditary or acquired angioedema (HAE or AAE) with and without C1 inhibitor (C1-INH) deficiency. Methods: In a prospective investigation, APTT and other coagulation parameters were determined in 149 adult patients with various types of angioedema and in 26 healthy participants (HP). Results: Mean APTT was significantly shortened in HAE-C1-INH type I (p Conclusions: A shortened APTT may help to diagnose HAE-C1-INH and AAE-C1-INH when determination of C1-INH is not yet available.