A patient with a history of easy bruising and prolonged bleeding after trauma is diagnosed with a coagulation disorder. Which of the following tests would be most useful in diagnosing the underlying cause of this patient's condition?

A Prothrombin time (PT)
B Partial thromboplastin time (PTT)
C Bleeding time
D Platelet aggregation study
The partial thromboplastin time (PTT) is a test used to evaluate the intrinsic and common coagulation pathways, and an abnormal result can indicate a deficiency or dysfunction of one or more coagulation factors.
Williams Hematology
Hematology Hematology: Coagulation Disorders Hematology: Coagulation Disorders Medium MEDICAL Confidence: high