RDW-SD
RDW-SD (Red Cell Distribution Width – Standard Deviation) is a blood test parameter that measures the variation in the size of red blood cells (RBCs). It provides a direct measurement of the width of the RBC size distribution and helps in identifying differences in cell sizes, which is known as anisocytosis. RDW-SD is an important part of the Complete Blood Count (CBC) and is used along with other red cell indices like MCV, MCH, and MCHC for accurate diagnosis.
An increased RDW-SD value indicates a higher variation in red blood cell sizes, which is commonly seen in conditions such as iron deficiency anemia, vitamin B12 or folic acid deficiency, and mixed types of anemia. A normal RDW-SD suggests uniformity in RBC size and is generally associated with normal blood conditions. This test helps doctors differentiate between different types of anemia and identify underlying causes more precisely.
The RDW-SD test is simple and requires a small blood sample. Accurate results assist healthcare professionals in diagnosing and monitoring blood disorders, ensuring proper treatment and better management of a patient’s health.