Difficulty: Medium
Average Score: 65%
Full-length
An 8-year-old boy has been diagnosed with hemophilia. Which of the following diagnostic blood studies is characteristically abnormal in this disorder?
Correct answer
A
Rationale
Partial thromboplastic time measures activity of thromboplastin, which depends on the intrinsic clotting factors deficient in children who are hemophiliacs. Platelet counts are normal in hemophilia. Hemophilia does not affect the complete blood count. Bleeding times are normal in hemophiliacs. They measure the time interval for the bleeding from small superficial wounds to cease.