**Question:** In sickle cell anemia, all are true except -

A. Increased red blood cell (RBC) deformability
B. Normal hemoglobin (Hb) level
C. Decreased RBC life span
D. Normal oxygen carrying capacity

**Core Concept:**
Sickle cell anemia is a hereditary disorder characterized by hemoglobin (Hb) abnormalities, resulting in deformable RBCs that take on a sickle shape under low oxygen tension. This leads to vaso-occlusion, chronic hemolysis, and anemia.

**Why the Correct Answer is Right:**
Option B ("Normal hemoglobin level") is incorrect because hemoglobin S (HbS) predominates in sickle cell anemia, leading to abnormal oxygen binding and reduced RBC stability. The resulting HbS polymerization causes RBCs to adopt a sickle shape, which is the primary pathophysiology of the disease.

**Why Each Wrong Option is Incorrect:**
Option A ("Increased red blood cell deformability") seems contradictory due to the sickle shape of RBCs caused by HbS polymerization. Increased deformability would be expected in normal RBCs, not in sickle cell anemia.

Option C ("Decreased red blood cell life span") is incorrect because, despite the abnormal RBCs, the overall survival of these cells is not significantly affected in sickle cell anemia.

Option D ("Normal oxygen carrying capacity") is incorrect as HbS has reduced affinity for oxygen, causing RBCs to release oxygen more easily at tissue sites, leading to hypoxia and tissue damage.

**Clinical Pearl:**
Understanding the abnormal hemoglobin and its effects is essential for diagnosing and managing patients with sickle cell anemia. Adequate management involves pain management, prevention of complications (e.g., pulmonary hypertension, stroke), and addressing chronic complications (e.g., leg ulcers, chronic renal disease).