Part 2: Immune Thrombocytopenia
Thomas G. DeLoughery, MD, FACP
Professor of Medicine, Pathology, and Pediatrics, Division of Hematology/Medical Oncology, Knight Cancer Center, Departments of Medicine and Pediatrics, and Division of Laboratory Medicine, Department of Pathology, Oregon Health Sciences University, Portland, OR
A 25-year-old woman presents with bruising. Exam shows petechiae on the shins but no other findings. Neither lymphadenopathy nor splenomegaly is present. Platelet count performed 15 months ago was 345 x 103/µL. There is no family history of bleeding, and the patient has not started any new medications in the past year. Platelet count at this visit is 3 x 103/µL. The patient's blood smear is normal. Which of the following findings is most helpful in making the diagnosis of ITP?