Fast Five Quiz: Hemophilia

Emmanuel C. Besa, MD


September 21, 2021

Laboratory studies for suspected hemophilia include a complete blood cell count, coagulation studies, and factor assays. If the factor activity is less than 40% of normal, hemophilia is usually the diagnosis. Molecular genotyping is recommended to confirm the diagnosis and aid in prediction of disease severity. Never delay indicated coagulation correction pending diagnostic testing.

Usually, the aPTT is prolonged in patients with hemophilia; however, a normal aPTT does not exclude mild or even moderate hemophilia. The aPTT is significantly prolonged in severe hemophilia. Platelet counts are usually normal. On coagulation studies, the bleeding time and prothrombin time (which assesses the extrinsic coagulation pathway) are typically normal in patients with hemophilia A or hemophilia B.

Read more about the workup of hemophilia.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.