[Effect of activators for activated partial thromboplastin time test on its results in the tube and automated test versions]. / Vliianie aktivatorov, primeniaemykh v teste AChTV, na ego rezul'taty v probirochnom i apparatnom ispolnenii.

Effects of activators used in combination with partial thromboplastin (PT), manufactured by the Kirov Institute of Hematology and Blood Transfusion, on the results of the activated partial thromboplastin time (APTT) test and its sensitivity to heparin were studied. Kaolin manufactured in Russia and by Aldrich firm and silica from Sigma were used. The method was reproduced in tubes and on Organon Teknika photooptic coagulometers: semiautomatic Coag-A-Mate XM and automated Coag-A-Mate RA-4. The concentration and optical density of the activator affected the results of APTT test, which prompts the use of kits calibrated for the PT/activator combination but not separate reagents. Combination of PT manufactured by the Kirov Institute and suspension of Russian kaolin ensured high sensitivity of the method to heparin content in the plasma and good reproducibility of the method both in tubes and on Organon Teknika coagulometers: coefficient of variation of APTT in all variants of the tube test were no higher than 10% and in the automated variant 2.6-6.2%.

[The use of lyophilized plasma as a reference sample for determining factor VIII]. / Ispol'zovanie liofilizirovannoi plazmy kak referentnogo obraztsa dlia opredeleniia faktora VIII.

The activity of lyophilized Soviet reference plasma Factor VIII was measured by a single-stage Papayan and Khrolova's method. This factor is referent in respect of the prothrombin complex factors, stored for 18-43.5 months. Factor VIII activity was found to be within 55-135 percent. Differences in the values of antihemophilic globulin activities obtained in parallel studies in different days may be explained by the fact that the native control was not standard. The results are promising as regards the possibility of using lyophilized donor reference plasma as a reference reagent for estimation of Factor VIII activity.

[The evaluation of lyophilized plasma as a reference standard for the prothrombin complex]. / Otsenka liofilizirovannoi plazmy v kachestve standarta dlia protrombinovogo kompleksa.

Analysis of a number of parameters of a lyophilized donor plasma reference sample to be used for the assessment of the prothrombin complex factors has shown the stability of this sample over the course of 14 months (a follow-up period). The sample may be used as a reference one in estimation of plasma prothrombin complex factor activities, and of PPSB activity. The reference sample activity should be estimated from the fresh donor plasma native pool, whose procoagulant activity is conventionally estimated as 100% or 1 U/ml. Use of a lyophilized reference sample helps obtain objective results compatible within this country, particularly so if all biologic reagents included in the test systems are standardized.

[Lyophilized plasma for use in calculating the activity of the prothrombin complex factors]. / Liofilizirovannaia plazma dlia rascheta aktivnosti faktorov protrombinovogo kompleksa.

Soviet lyophilized donor reference plasma (a reagent), intended for plotting a calibration graph or for calculating the activities of prothrombin factors (index) according to a formula, is stable for 12-14 months. It is fit for the aforesaid purposes with the blood plasma of both donors and patients suffering from various degrees of the studied procoagulant deficits.

[A lyophilized reagent for standardization of the activated partial thromboplastin time]. / Liofilizirovannyi reagent dlia standartizatsii aktivirovannogo partsial'nogo tromboplastinovogo vremeni.

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.

[Evaluation of methods of studying hemostasis]. / Otsenka nekotorykh metodov issledovaniia gemostaza.

Comparative assessment of the methods for studies of platelet aggregation, used in the USSR and in Hungary, has demonstrated the usefulness and reproducibility of both. The reagents manufactured by Reanal (Hungary) are characterized by a higher sensitivity, inducing a more distinct and rapid formation of aggregates. This fact is of particular importance when no aggregometers are available and the 'snow whirl' is assessed visually. Another advantage of the Hungarian aggregants is the presence of the whole set of reagents in the kit and standardization of these reagents. Assessment of the activated partial thromboplastin time of mixed donor native plasma with the use of the Soviet native partial thromboplastin stored frozen and with the use of the Reanal reagent has demonstrated a high variability of the results; this may be explained by the employment of nonstandard reference plasma. The advantages of the imported lyophilized reagent are a year's shelf life and the possibility of transportation.