Zinc, RBC is a specialized test that measures zinc levels within red blood cells, providing a more accurate assessment of long-term zinc status than serum zinc measurements. This test is essential for evaluating zinc deficiency, which can cause impaired immune function, delayed wound healing, taste and smell disturbances, and growth retardation in children. Zinc is a critical cofactor for over 300 enzymes involved in DNA synthesis, protein metabolism, and immune function. Low zinc levels are associated with various conditions including alcoholic cirrhosis, cystic fibrosis, myocardial infarction, acute and chronic infections, and certain skin disorders. Elevated levels may indicate industrial exposure or zinc supplementation. This test is particularly valuable for patients with chronic diseases, malabsorption syndromes, or those on long-term medications that may affect zinc absorption.