Hemophilia A is an inherited bleeding disorder caused by a deficiency in clotting factor VIII. It prevents proper blood clotting and can lead to prolonged bleeding. Hematology uses automated analyzers to perform a complete blood count and tests like activated partial thromboplastin time to diagnose Hemophilia A, indicated by an increased aPTT time. The deficiency in clotting factor VIII is caused by an X-linked recessive gene mutation. Symptoms vary depending on severity and can include pain, swelling, bleeding, and organ damage if not properly managed.