## **Core Concept**
The question revolves around diagnosing a specific type of anemia in an infant with a hemoglobin (Hb) level of 6 gm%, characterized by target cells on peripheral blood smear and a positive family history. This clinical presentation suggests a hereditary cause, likely a hemoglobinopathy.

## **Why the Correct Answer is Right**
The presence of target cells in the peripheral blood smear, along with severe anemia and a positive family history, points towards a diagnosis of hereditary hemoglobinopathy, such as beta-thalassemia major. **High-performance liquid chromatography (HPLC)** or **capillary electrophoresis** are considered gold standards for diagnosing hemoglobinopathies as they can accurately quantify the different types of hemoglobin present in the blood. This is crucial for confirming the diagnosis and differentiating between various hemoglobinopathies.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While a **Complete Blood Count (CBC)** can provide information on the severity of anemia and some indices (like MCV, MCH, MCHC) that might suggest a microcytic hypochromic anemia, it cannot specifically diagnose the type of hemoglobinopathy.
- **Option B:** **Peripheral Blood Smear** can show characteristic features like target cells but cannot provide a definitive diagnosis of the specific hemoglobinopathy.
- **Option D:** **Bone Marrow Examination** can show erythroid hyperplasia indicative of chronic anemia but is not specific for diagnosing hemoglobinopathies and is more invasive.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that in cases of suspected hemoglobinopathies, especially in regions with a high prevalence of thalassemias, early diagnosis through **HPLC** or genetic testing can significantly impact management, including the need for regular blood transfusions and potential for bone marrow transplantation.

## **Correct Answer:** . **High-performance liquid chromatography (HPLC)**