Hemoglobin is the most important component of red blood cells. It is composed of a protein called heme, which binds oxygen. In the lungs, oxygen is exchanged for carbon dioxide.
Abnormalities of an individual's hemoglobin value can indicate defects in the normal balance between red blood cell production and destruction. Both low and high values can indicate disease states.
Update Date 2/25/2014
Updated by: Sameer Patel, MD, Assistant Professor of Pediatrics, Northwestern University, Feinberg School of Medicine, Chicago, IL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.