Read this in Hindi. What does it mean when your doctor says that your haemoglobin levels are below normal? Haemoglobin (Hb) is a protein found in the red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs. It gives blood its red colour. Haemoglobin levels vary from person to person. The normal range for haemoglobin for men is 13.5 to 17.5 grams per decilitre. For women it is 12.0 to 15.5 grams per decilitre. A low haemoglobin count on a blood test may be due to a condition