RESUMEN
The separation and determination of Warfarin as anticoagulant Coumarin in serum was done, after the extraction by high performance liquid chromatography reverse phase [HPLC-RP], where we have extracted serum with two special methods, they were solid-liquid extraction [SPE: sep-pack plus Cartridge] and liquid-liquid extraction. Methods of extraction were accurate and sensitive depending on qualitative and quantitative studies, that Regression coefficient was 0.9997, Variation coefficient was between 0.3-2% and limit of detection was 1.5 micro g/ ml. The best mobile phase was achieved by 95% methanol, 5% water [pH = 4] using ODS S micro m [4.6 mm x 250 mm] Nucleosil. The determination method was applied to qualify serum Warfarin concentration from patient's serum using it as anticoagulant oral tablets. That method has given good sensitive accurate results which are used in routine clinical control in medical laboratories