What is Hemoglobin?

Hemoglobin is a protein in your red blood cells that carries oxygen from your lungs to the rest of your body and returns carbon dioxide from your tissues back to your lungs. It gives blood its red color and is one of the most commonly tested biomarkers in a complete blood count (CBC).

Why is it Important?

Hemoglobin levels indicate your blood's ability to transport oxygen. Abnormal levels can signal a range of conditions, from common nutritional deficiencies to more serious blood disorders.

Normal Ranges

Reference ranges vary by sex, age, and laboratory. The values below are general guidelines.

Group	Range	Unit
Adult Male	13.5 – 17.5	g/dL
Adult Female	12.0 – 15.5	g/dL
Pregnant	11.0 – 14.0	g/dL
Children (6–12 yr)	11.5 – 15.5	g/dL

What Do Abnormal Results Mean?

Low Hemoglobin (Anemia)

Common causes include:

Iron deficiency
Vitamin B12 or folate deficiency
Chronic diseases (kidney disease, cancer)
Blood loss (menstruation, GI bleeding)
Bone marrow disorders

High Hemoglobin

Common causes include:

Dehydration
Living at high altitudes
Chronic lung disease
Polycythemia vera
Smoking

When Should You Get Tested?

Hemoglobin is part of a standard CBC panel. Your doctor may order it if you experience fatigue, weakness, shortness of breath, or dizziness — symptoms that can indicate anemia or other blood-related conditions.