Hemophilic A has following diagnostic features except –
## **Core Concept**
Hemophilia A, also known as classic hemophilia, is a genetic disorder caused by missing or defective **factor VIII**, a crucial protein for blood clotting. This condition leads to prolonged bleeding, particularly into joints and muscles. Diagnosis involves a combination of clinical presentation and laboratory tests.
## **Why the Correct Answer is Right**
The correct answer, **prolonged PT (Prothrombin Time)**, is not a diagnostic feature specific to Hemophilia A. Hemophilia A affects the intrinsic pathway of coagulation, which is reflected in the **aPTT (activated partial thromboplastin time)**, not the PT. PT measures the extrinsic and common pathways of coagulation. Therefore, in Hemophilia A, aPTT is prolonged, while PT is typically normal.
## **Why Each Wrong Option is Incorrect**
- **Option A:** **Low levels of factor VIII** - This is a diagnostic feature of Hemophilia A. The condition is characterized by a deficiency in factor VIII.
- **Option B:** **Prolonged aPTT** - This is also a diagnostic feature. The aPTT test is used to assess the intrinsic and common pathways of coagulation, which are affected in Hemophilia A.
- **Option D:** **Family history of bleeding** - This is often present in Hemophilia A, as it is an X-linked recessive disorder, meaning it primarily affects males and is inherited from carrier mothers.
## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Hemophilia A and Hemophilia B (caused by factor IX deficiency) can present similarly, but they are distinguished by specific factor assays. Remember, Hemophilia A is treated with **factor VIII concentrates**, and a significant complication is the development of **inhibitors** against factor VIII.
## **Correct Answer:** . Prolonged PT