CBC Test Explained: Hemoglobin, WBC & Platelets Complete Guide

Whether you visit a doctor for a routine checkup, fatigue, fever, or prior to a surgery, a Complete Blood Count (CBC) test is almost always prescribed. A CBC measures the cells that make up your blood: red blood cells, white blood cells, and platelets. Understanding these values helps detect infections, anemia, leukemia, and various other disorders.

1. Red Blood Cells (RBC) & Hemoglobin

RBCs carry oxygen from your lungs to the rest of your body. Hemoglobin (Hb) is the iron-rich protein in RBCs that actually binds to oxygen.

• Low Hemoglobin: Indicates Anemia, causing fatigue, pale skin, cold hands, and shortness of breath.
• High RBC Count: Can be caused by dehydration, smoking, high altitude, or bone marrow disorders.

2. White Blood Cells (WBC) - The Immune Shield

WBCs protect the body against infections and diseases. A CBC report breaks down WBCs into five main types (Neutrophils, Lymphocytes, Monocytes, Eosinophils, and Basophils) as a differential count.

• High WBC Count (Leukocytosis): Signals that your body is fighting off an infection or inflammation. It can also be triggered by high stress or certain medications.
• Low WBC Count (Leukopenia): Makes you susceptible to infections. It can be caused by viral infections, autoimmune conditions, or bone marrow issues.

3. Platelets (PLT) - Clotting Factors

Platelets are tiny cell fragments essential for blood clotting. When you get a cut, platelets clump together to stop the bleeding.

• Low Platelet Count (Thrombocytopenia): Increases risk of bruising and bleeding. Often associated with viral fevers like Dengue.
• High Platelet Count (Thrombocytosis): Can lead to abnormal blood clots in blood vessels, increasing risk of stroke or heart attack.