Function of hemoglobin in human body

 

Hemoglobin is an iron-containing protein in the blood of many animals that, in vertebrates, carries oxygen from the lungs to the tissues of the body and carries carbon dioxide from the tissues to the lungs. Hemoglobin is contained in the red blood cells of vertebrates and gives these cells their characteristic color. Hemoglobin is also found in many invertebrates, where it circulates freely in the blood.

Why the Hemoglobin Test is Performed

The hemoglobin test is a common test and is almost always done as part of a complete blood count (CBC). The reasons or conditions for having the hemoglobin test include:

 

Symptoms such as fatigue, poor health, or unexplained weight loss.

Signs of bleeding.

Before and after major surgery.

During pregnancy.

Chronic kidney disease or many other chronic medical problems.

Monitoring of anemia and its cause.

Monitoring during treatment for cancer.

Monitoring medicines that may cause anemia or low blood counts.

 

Normal Results

Normal results for adults vary, but in general are:

 

Male: 13.8 to 17.2 grams per deciliter (g/dL) or 138 to 172 grams per liter (g/L)

Female: 12.1 to 15.1 g/dL or 121 to 151 g/L

Normal results for children vary, but in general are:

 

Newborn: 14 to 24 g/dL or 140 to 240 g/L

Infant: 9.5 to 13 g/dL or 95 to 130 g/L

The ranges above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your health care provider about the meaning of your specific test results.

 

1. Effects of high and low hemoglobin on the body，the normal level

 

LOWER THAN NORMAL HEMOGLOBIN

 

Low hemoglobin level may be due to:

 

Anemia caused by red blood cells dying earlier than normal (hemolytic anemia)

Anemia (various types)

Bleeding from digestive tract or bladder, heavy menstrual periods

Chronic kidney disease

Bone marrow being unable to produce new red blood cells. This may be due to leukemia, other cancers, drug toxicity, radiation therapy, infection, or bone marrow disorders

Poor nutrition (including low level of iron, folate, vitamin B12, or vitamin B6)

Low level of iron, folate, vitamin B12, or vitamin B6

Other chronic illness, such as rheumatoid arthritis

 

HIGHER THAN NORMAL HEMOGLOBIN

 

High hemoglobin level is most often caused by low oxygen levels in the blood (hypoxia), present over a long period of time. Common reasons include:

 

Certain birth defects of the heart that are present at birth (congenital heart disease)

Failure of the right side of the heart (cor pulmonale)

Severe chronic obstructive pulmonary disease (COPD)

Scarring or thickening of the lungs (pulmonary fibrosis) and other severe lung disorders

Other reasons for high hemoglobin level includes:

 

A rare bone marrow disease that leads to an abnormal increase in the number of blood cells (polycythemia vera)

The body having too little water and fluids (dehydration)