This comprehensive book offers an in-depth overview of laboratory diagnoses for both inherited and acquired thrombophilias, illuminating the complex interplay between genetic and environmental factors that contribute to venous thromboembolism. Beginning with foundational concepts in thrombophilia testing, the book systematically covers the diagnosis of key anticoagulant deficiencies, including protein C, protein S, protein Z, antithrombin, and plasminogen, as well as the critical evaluation of prothrombin G20210A and factor V Leiden mutations and other factors involved in thrombosis. It also addresses acquired thrombophilia, highlighting the significant impact of factors such as hyperhomocysteinemia and the influence of medications, lifestyle choices, and underlying health conditions on thrombosis risk. Each chapter clarifies the principles behind various laboratory assays, detailing the preanalytical variables that can affect results and guiding the interpretation of findings. Real-world challenges in thrombophilia testing such as during pregnancy, the use of oral contraceptives, and monitoring anticoagulation therapy are specifically examined. Written in a clear yet comprehensive style, this book is aimed at thrombosis specialists, hematologists, laboratory scientists, and students. It provides extensive knowledge, practical guidance, and evidence-based protocols for thrombophilia testing, ensuring accurate diagnosis and effective management of this life-threatening disorder.