Specific Functional and Immunologic Assay of Plasma Plasminogen in Hereditary Angioedema, in Hereditary Angioedema Treated with Tranexamic Acid, and in Normal Subjects¹

Plasma plasminogen levels were determined by a specific esterolytic assay and a radial immunodiffusion assay, both of which were standardized on a weight basis by using highly purified plasminogen diluted in plasminogen-free plasma. In thirteen normal individuals the functional and antigenic levels were 275 ± 61 µg/ml and 285 ± 61 µg/ml, respectively (r = 0.95), whereas in 58 plasmas from individuals with hereditary angioedema the levels were 272 ± 58 µg/ml and 265 ± 64 µg/ml, respectively (r = 0.89). In two patients treated with tranexamic acid either acutely or chronically, both the functional and antigenic plasminogen levels were diminished.