The reference ranges for hemoglobin concentration in adults are as follows: Men: 14.0-17. Hemoglobin is a protein in red blood cells that carries oxygen and carbon dioxide. Learn about normal hemoglobin levels by age and gender, causes and symptoms of low or high hemoglobin, and how to measure hemoglobin with a blood test. Find out what constitutes normal haemoglobin levels and their significance for overall health. Learn about the range of haemoglobin levels and the factors affecting them. Normal hemoglobin values are related to the person's age and sex. Normal values may vary slightly between test systems, and which groups of doctors have determined "normal values" for their group of patients; however, the value ranges are close (vary by about 0.5 g/dl) for almost every group.
