What Is Hemoglobin in a Blood Test?

Hemoglobin (Hb) is the iron-containing protein in red blood cells that carries oxygen from your lungs to every tissue in your body.

Normal Ranges

• Men: 13.5–17.5 g/dL
• Women: 12.0–15.5 g/dL
• Pregnancy: lower (11.0 g/dL) due to hemodilution

Low Hemoglobin (Anemia) Causes

• Iron deficiency — most common cause globally
• Vitamin B12 or folate deficiency
• Chronic disease — kidney disease, cancer, inflammation
• Blood loss — heavy menstruation, GI bleeding
• Hemolysis — premature red cell destruction
• Bone marrow disorders

Symptoms of Low Hemoglobin

• Fatigue and weakness
• Shortness of breath on exertion
• Pale skin
• Dizziness
• Rapid heartbeat
• Cold hands and feet

High Hemoglobin Causes

• Dehydration — hemoconcentration
• Chronic lung disease — compensatory
• High altitude living
• Smoking
• Polycythemia vera
• Testosterone use