Macroscopic Studies of Platelet Agglutination; Nature of Thrombocyte Agglutinating Activity of Plasma.

Abstract

1. Optimal conditions for platelet agglutination were determined in the dog by a macroscopic test. Most rapid agglutination was observed with Mg++ or Mn++, undiluted plasma, and a platelet concentration above 200,000/cmm. Frozen or heated platelets were not agglutinable. 2. The thrombocyte agglutinating (TAg) factor found in plasma was thermolabile and non-dialyzable. Under optimal conditions it caused gross platelet clumping in 5-15 seconds. This factor was active in the absence of fibrin coagulation, Ca++, fibrinogen, AHF, prothrombin and related coagulant factors, suggesting the TAg may act independently of the coagulation process.