[A lyophilized reagent for standardization of the activated partial thromboplastin time]

Native partial thromboplastin, prepared from cadaver brain thromboplastin (a reagent), is a cephalin analog used to detect disorders in the first phase of coagulation. It was lyophilized with the aim of its stabilization, potential commercial manufacture, and introduction into practical clinical laboratories. Native emulsion was distributed into 0.2 ml penicillin flasks and lyophilized for 18-20 hrs in IZ-9 (CSR) or similar equipment at the maximum temperature of the product 5 degrees C. Lyophilized reagent is a white or slightly cream-colored powder. It retains its activity for at least a year as evidenced by the activated partial thromboplastin time test. The range of activities within one lot is less if commercial lyophilized donor reference plasma is used in the test. The reagent is stored in a refrigerator at 4-8 degrees C.