A 6 months old infant with Hb of 6 gm% has peripheral blood showing target cells & increased reticulocytes. Family history of similar complaints is Positive. Diagnosis can be best done with which of the following?
First, I need to think about the possible diagnoses. Target cells and reticulocytosis suggest a hemolytic anemia. The family history points to a genetic disorder. Common inherited anemias with target cells include beta-thalassemia and sickle cell disease. But sickle cell would show sickle cells on the smear, not target cells. Beta-thalassemia minor is common in children with a family history. However, the Hb level is very low here, which might suggest a more severe form like beta-thalassemia major, but that's usually diagnosed in children younger than 2 years. Alternatively, hereditary spherocytosis can cause anemia, but they have spherocytes, not target cells. Iron deficiency anemia can also cause microcytic anemia and target cells, but the reticulocyte count would be low in iron deficiency unless there's a recent blood loss. However, there's a family history here, so iron deficiency is less likely.
The key here is the combination of target cells, reticulocytosis, and family history. Beta-thalassemia is a strong possibility. To confirm beta-thalassemia, the best test would be hemoglobin electrophoresis. This test can detect abnormal hemoglobins and quantify the types present. In beta-thalassemia, there's an increase in Hb A2 and sometimes Hb F. Other tests like peripheral smear might show microcytic RBCs, but electrophoresis is more specific. If the options included hemoglobin electrophoresis, that would be the answer. The question's options are missing, but based on the scenario, the correct answer is likely hemoglobin electrophoresis. Let me check if there are other possibilities. For example, alpha-thalassemia can present similarly, but the peripheral smear might show different findings. The family history and the presence of target cells point more to beta-thalassemia. So the best diagnostic test would be hemoglobin electrophoresis to confirm the type of thalassemia.
**Core Concept**
This question assesses the diagnosis of inherited hemolytic anemias, particularly **beta-thalassemia**, based on clinical presentation and laboratory findings. Key features include microcytic anemia, target cells, reticulocytosis, and a positive family history.
**Why the Correct Answer is Right**
The infant’s presentation of **target cells** and **reticulocytosis** with a family history is classic for **beta-thalassemia**. **Hemoglobin electrophoresis** is the confirmatory test, as it detects **elevated Hb A2 (>3.5%)** and **Hb F** in beta-thalassemia trait. In severe cases (beta-thalassemia major), Hb A is nearly absent. This test distinguishes thalassemia from other microcytic anemias like iron deficiency (which shows low ferr