Blood contains red blood cells, white blood cells, and platelets, as well as a fluid portion termed plasma. We primarily study blood platelets, but sometimes we also analyze the blood of patients with red blood cell disorders (such as sickle cell disease), white blood cell disorders, and disorders of the blood clotting factors found in plasma. Blood platelets are small cell fragments that help people stop bleeding after blood vessels are damaged. Some individuals have abnormalities in their blood platelets that result in them not functioning properly. One such disorder is Glanzmann thrombasthenia. Most such patients have a bleeding disorder characterized by nosebleeds, gum bleeding, easy bruising (black and blue marks), heavy menstrual periods in women, and excessive bleeding after surgery or trauma. Our laboratory performs advanced tests of platelet function and platelet biochemistry. If we find evidence that a genetic disorder may be responsible, we analyze the genetic material (DNA and RNA) from the volunteer, and when possible, close family members to identify the precise defect.