175COMPARISON BETWEEN THE PERFORMANCE OF LOCALLY PREPARED THROMBOPLASTIN AND A COMMERCIAL BRANDProthrombin Time (PT) is the test which measures the extrinsic pathway of coagulation in the presence of an optimal concentration of tissue extract from thromboplastin. The quality of the later is the whole mark the sensitivity of the test and the international normalize ratio (INR) is being created to make inter laboratory comparison between PTs. To prepare different brain extracts from rabbits, sheep and test their performance compared to commercial brand.Thromboplastins were prepared using standard manual method from brains of rabbits and sheep for preparation: single rabbit brain (SRB), two mixed rabbit brains (TMRB), freeze dried single rabbit brain (FDSRB) and single sheep brain (SSB). The study involved 100 citrated venous blood specimen. Plasma was separated immediately and was tested. The data was analyzed statistically by using SPSS program version- II to compare between the means of locally prepared reagents and the commercial brand. The result of PT showed significant differences when compared with the commercial brand (P. Value 000). The international sensitivity (ISI) compared to the (1.52) with ISI of the commercial brand. The best one of the locally prepared thromboplastin was (FSRB) with an ISI 1.76. The sensitivity tests for (SRB), (TMRB), (FSRB) and (SSB) were respective 75%, 70%, 80%, 31%. The raw materials for local thromboplastins are available, cheap and easy to be extracted and prepared, but should be corrected by ISI, the recommended reference preparation is the freeze dry one.gadobio77@hotmail.comResearch512015Thromboplastin,Prothrombin Time,rabbit brains,SudanSalma O.M. Abdalla,Shamseldein M. Ahamed,Ahmed A. Mohamedani,GadAllah Modawe Faculty of Medical Laboratory Science, Department of Clinical Chemistry, University of Gezira, Wad Medani, Sudan, Faculty of Medical Laboratory Science, Department of Clinical Chemistry, University of Gezira, Wad Medani, Sudan,2 Department of Pathology, Faculty of medicine, University of Gezira, Wad Medani, Sudan.,Faculty of Medicine, Department of Biochemistry, Omdurman Islamic University, Omdurman,Sudan