Which of the following laboratory tests is used to diagnose and monitor the treatment of hemophilia B?

A Prothrombin time (PT)
B Partial thromboplastin time (PTT)
C Factor IX assay ✓
D Bleeding time

Explanation

Factor IX assay is a specific test used to diagnose and monitor the treatment of hemophilia B, which is caused by a deficiency of factor IX.

Mnemonic

FIX = Factor IX

Source

Williams Hematology
Hematology Hematology: Coagulation Disorders Hematology: Coagulation Disorders Easy MEDICAL Confidence: high