What could cause low or high hemoglobin levels? The typical range for hemoglobin varies by age, sex, and pregnancy status. Abnormal levels may indicate underlying health conditions.

Understanding Hemoglobin Levels

Hemoglobin (Hgb) is a crucial protein found in red blood cells that helps transport oxygen from the lungs to the body’s tissues and carbon dioxide back to the lungs. Abnormally high or low Hgb levels can lead to various symptoms and may indicate underlying health conditions.

Factors Affecting Hemoglobin Levels

An individual’s Hgb levels can vary based on age, sex, and pregnancy status. Typical healthy Hgb levels are:

• For men: Below 13 g/dL is considered low
• For women: Below 12 g/dL is considered low if not pregnant

These thresholds may change depending on certain conditions and can also vary based on the laboratory’s reference range. Hemoglobin levels in children, especially infants under 6 months, may also differ.

Causes of Low Hemoglobin (Anemia)

Low Hgb, also known as anemia, can have various causes, including:

• Lack of iron, folate, or vitamin B-12 in the diet, making it harder for the bone marrow to produce Hgb
• Severe blood loss after surgery or a major injury
• Internal bleeding from conditions like stomach ulcers, stomach or colon cancer, or internal injuries
• Genetic conditions like sickle cell anemia that cause abnormal red blood cell shape and reduced Hgb capacity
• Hypothyroidism, which can lead to a deficiency in red blood cell production
• Enlarged spleen (splenomegaly) from infection, liver conditions, or cancer
• Bone marrow conditions like leukemia that prevent adequate red blood cell production
• Chronic kidney disease, which can result in a deficiency of the hormone erythropoietin that stimulates red blood cell production

Other causes of low Hgb include donating blood too often and heavy menstrual bleeding.

Causes of High Hemoglobin

Abnormally high Hgb levels, known as polycythemia, can also occur due to various reasons, including:

• Dehydration, which can concentrate the number of red blood cells in the blood
• Chronic obstructive pulmonary disease (COPD) or other lung conditions that reduce oxygen levels in the blood
• Congenital heart disease that reduces oxygen levels in the blood
• Certain types of kidney cancer or other cancers that overproduce erythropoietin, leading to excess red blood cell production
• Living at high altitudes, where the body adapts by producing more red blood cells to compensate for lower oxygen levels

Symptoms of Abnormal Hemoglobin Levels

Symptoms of both low and high Hgb levels can include:

• Fatigue and exhaustion
• Dizziness or lightheadedness
• Shortness of breath
• Abnormal or rapid heartbeat
• Chest pain
• Cold or swollen hands and feet
• Headaches
• Difficulty with physical activity

If you are experiencing any of these symptoms, it’s important to consult your healthcare provider for appropriate testing and diagnosis.

The Hemoglobin Test

The Hgb test is a common blood test that measures the amount of hemoglobin in your red blood cells. It is often performed as part of a complete blood count (CBC) test, which also analyzes other blood components like white blood cells and platelets.

To conduct the Hgb test, a healthcare professional will draw a small sample of blood, usually from a vein in your arm or by pricking your finger. The sample is then sent to a lab for analysis.

You typically don’t need to fast for the Hgb test specifically, but if your doctor plans to test the chemistry of your blood, you may need to avoid food and liquids with calories for about 12 hours prior to the test.

Understanding Test Results

Interpreting your Hgb test results is important to identify any underlying health conditions. While the typical ranges may vary, generally:

• Low Hgb (anemia) is indicated by levels below 13 g/dL for men and 12 g/dL for non-pregnant women.
• High Hgb (polycythemia) is indicated by levels above the normal range, which can vary depending on factors like age, sex, and pregnancy status.

If your Hgb levels are abnormal, your healthcare provider will work with you to determine the underlying cause and develop an appropriate treatment plan.