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Hemoglobin - Average, High and Low Values

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Hemoglobin - Average, High and Low Values

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Hemoglobin is a protein molecule of RBC that provides oxygen to the tissues. Read the article mentioned below.

Medically reviewed by

Dr. Rajesh Gulati

Published At July 20, 2022
Reviewed AtFebruary 20, 2023


Hemoglobin is an iron-containing protein competent in the red blood cells that transports oxygen to the tissues and organs. In the oxygenated state, it is called oxyhemoglobin and has the color of the blood - bright red. In the reduced state, it changes to a purplish-blue color. Hemoglobin is developed in the bone marrow. When red blood cells are used, hemoglobin is broken down, and the iron is rescued. The rescued iron is then transported by proteins (transferrin) in the bone marrow and re-used to generate new red blood cells. The left-over hemoglobin forms the basis of bilirubin.

What Is Hemoglobin?

Hemoglobin (Hgb or Hb) is the protein molecule of red blood cells that supply the oxygen from the lungs to the body's tissues and extracts carbon dioxide back to the lungs. Hemoglobin indicates the body's oxygen level and the blood's iron levels. Hemoglobin is generally measured as a part of the routine complete blood count (CBC) test from a blood sample.

What Is the Normal Hemoglobin Level?

The hemoglobin level is referred to as the amount of hemoglobin in grams (gm) per deciliter (dL) of the whole blood, a deciliter being 100 milliliters. The normal range for hemoglobin is calculated based on age and the gender of the person. The normal ranges of hemoglobin are:

  • Newborns: 17 to 22 gm/dL.
  • One week: 15 to 20 gm/dL.
  • One month: 11 to 15 gm/dL.
  • Children: 11 to 13 gm/dL.
  • Adult males: 14 to 18 gm/dL.
  • Adult females: 12 to 16 gm/dL.
  • Men above middle age: 12.4 to 14.9 gm/dL.

Pregnant women are recommended to avoid both high and low hemoglobin levels as it can lead to increased risks of stillbirths, premature birth, or low birth weight babies.

When Should I Get a Hemoglobin Test?

You may get a complete blood count to measure hemoglobin if you encounter signs and symptoms of low oxygen or low iron. These symptoms could be:

  • Tiredness.

  • Shortness of breath even during slight physical activity.

  • Light-headedness.

  • Skin that is lighter or yellower than usual.

  • Recurrent head pains.

  • Irregular heart rate.

Although less presented, high hemoglobin levels can also cause health problems. The CBC test may be advised if you have signs of abnormally high hemoglobin levels, such as:

  • Blurry or disturbed vision.

  • Repetitive headaches.

  • Slurred speech.

  • Redness is seen on the face due to an increase in hemoglobin, as it is red in color.

What Does a Low Hemoglobin Level Mean?

A low hemoglobin level denotes anemia or a low RBC count. Some of the common causes of anemia are:

  • Blood loss (traumatic injury, surgery).

  • Deficiency (iron, vitamin B12, folate).

  • Suppression of red blood cell synthesis by chemotherapy or kidney dysfunction.

  • Abnormal structure of hemoglobin (seen with sickle cell anemia or thalassemia).

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

  • Heavy menstrual periods.

  • Chronic kidney disease.

  • Deficient production of red blood cells in the bone marrow. This may be due to blood cancer, other drug toxicity, radiation therapy, infection, or bone marrow disorders.

  • Deficiency of iron, folate, vitamin B12, or vitamin B6.

  • Chronic illnesses, such as arthritis.

What Does a High Hemoglobin Level Mean?

Greater than normal hemoglobin levels are generally seen in people living at high altitudes and in smokers. Dehydration produces a false reading of high hemoglobin levels that vanishes when the fluid is balanced.

Some other infrequent causes of high hemoglobin levels are:

  • Chronic lung disease.

  • Certain tumors such as kidney cancer.

  • A disorder of the bone marrow known as polycythemia rubra vera in which the bone marrow produces too many red blood cells.

  • Abuse of erythropoietin by athletes for blood doping purposes (increasing the amount of oxygen available to the body by increasing the production of red blood cells).

  • Certain birth defects of the heart.

  • Dysfunction in the right side of the heart.

  • Severe chronic obstructive pulmonary disease (COPD).

  • Scarring or thickening of the lungs and other severe lung disorders.

What Is the Hemoglobin A1c Test?

Hemoglobin A1c or glycosylated hemoglobin is a vague indication of blood sugar control level in people with diabetes mellitus over three months. As a good amount of glucose (blood sugar) circulates in the blood on a daily basis, the greater the level of glucose is tied to the circulating hemoglobin. Normal hemoglobin A1c levels range approximately 35 mg/dL over 135 mg/dL. A hemoglobin A1c of six percent estimates an average blood sugar level of 135 mg/dL (milligrams per deciliters) over the previous three months.

How to Increase Your Hemoglobin Levels?

Low hemoglobin levels can occur in three circumstances such as:

  • Decrease in red blood cell production.

  • Altered bone marrow causes an increase in red blood cell destruction (seen with liver disease).

  • Blood loss from trauma (roadside accidents).

You can increase hemoglobin levels by treating the underlying problems and maintaining a healthy lifestyle. Some ways to increase the hemoglobin levels are discussed below:

  • Red blood cells transfusion (emergency procedure).
  • Starting erythropoietin (a hormone used to regenerate red blood cell production).

  • Taking iron and other nutrient supplements.

  • Intake of iron-rich foods (eggs, spinach, beans, lean meats, and seafood).

  • Foods that are rich in co-factors (such as vitamin B6, folic acid, vitamin B12, and vitamin C). Maintaining normal hemoglobin levels with foods such as fish, vegetables, nuts, cereals, peas, and citrus fruits.

You must not self-medicate for low hemoglobin levels without first discussing with your physician as side effects from these treatments and excess iron intake may cause severe side effects.


Identifying the underlying cause and treating the condition accordingly will help rectify your hemoglobin count. Keeping the hemoglobin levels in check and maintaining proper levels is essential for an individual's overall health. As this protein component of the red blood cells performs one crucial function of carrying oxygen from your lungs to your tissues, it is always safe to keep the levels tracked periodically. Most importantly, consuming a proper diet and following a proper lifestyle can help you maintain your hemoglobin at standard levels.

Frequently Asked Questions


What Is the Normal Value of Hemoglobin Level?

Hemoglobin is a type of protein that is present in red blood cells and helps in transferring oxygen to various parts of the body. Normal hemoglobin levels vary among adults; for females, it is 12 to 16 grams per deciliter (gm/dl), and for males, it is 14 to 18 grams per deciliter. Whereas normal hemoglobin levels in newborns are 17 to 22 grams per deciliter, in an infant, it is 9.5 to 13 grams per deciliter, and in children, it is 11 to 13 grams per deciliter.


What Are the Reasons for Low Hemoglobin?

A slight decrease in hemoglobin count does not cause a problem. Women who are pregnant and are on menstruation have low hemoglobin levels. Other causes of low hemoglobin levels are; if the body does not produce enough red blood cells in conditions such as aplastic anemia (a blood condition where the bone marrow cannot produce enough blood cells), intake of antiretroviral drugs for the treatment of HIV (human immunodeficiency virus) infection, chronic kidney disease, iron deficiency anemia, rheumatoid arthritis (an autoimmune disease which affects the joints) etcetera; conditions that destroy red blood cells are sickle cell anemia (a red blood cell disorder where the cell shape is abnormal and in sickle shape), thalassemia (an inherited disorder), enlarged spleen etcetera; and due to blood loss in conditions such as internal bleeding from ulcers, hemorrhoids, and cancers, frequently donating blood and heavy menstrual bleeding.


Can Low Hemoglobin Levels Have an Impact on Health?

Yes, low levels of hemoglobin can impact health and cause severe fatigue, heart problems such as arrhythmia (irregular heartbeat) due to lack of oxygen supply in the blood, which can result in heart failure or an enlarged heart, low hemoglobin levels in pregnant women can cause premature birth and low hemoglobin levels due to conditions such as sickle cell anemia, or thalassemia can cause life-threatening complications.


How to Increase the Levels of Hemoglobin and Can Consuming Bananas Increase the Levels of Hemoglobin?

Hemoglobin levels can be increased with the help of the intake of iron supplements and iron-rich food such as beef, beans, dried fruit, and dark green leafy vegetables; intake of folate-rich food such as fruits, green peas, kidney beans, rice, and pasta; vitamin B-12 rich food such as dairy products, and meat; and intake of vitamin C rich foods such as citrus fruits, strawberries, melons, and broccoli. In case of long-term anemia, blood transfusion, or injections of erythropoietin, a synthetic hormone can be used. In case of bone marrow defects (aplastic anemia), a bone marrow transplant can be done. Yes, bananas can increase hemoglobin levels as they contain high levels of iron that can stimulate the production of hemoglobin.


How to Test Hemoglobin Levels at Home?

Hemoglobin levels at home can be checked with the help of a smartphone app called anemoCheck, a mobile app which assesses the levels of hemoglobin through fingernails and is noninvasive, or a hemoglobin test kit in which a small prick is done on the finger to estimate the hemoglobin levels.


If the Level of Hemoglobin Is 6.5 Grams per Deciliter, What Does It Indicate?

If the levels of hemoglobin are 6.5 to 7.9 grams per deciliter, it indicates severe hemoglobin, and below 6.5 grams per deciliter indicates a life-threatening condition, which requires immediate treatment such as transfusion of packed red blood cells (PRBC).


What Are the Three Stages of Iron Deficiency Anemia?

Iron deficiency anemia occurs in three stages. In the first stage, iron levels are decreased, but this does not affect the red blood cells. In the second stage, the iron levels are low, and the process of forming red blood cells is altered; a condition called iron-deficient erythropoiesis is developed where the red blood cells do not contain enough levels of hemoglobin. In the third stage, iron-deficiency anemia develops, and hemoglobin levels are low. 


Can Stress Develop Anemia?

Yes, there is a connection between stress and anemia. Stress can cause specific physiological changes by affecting the diet, and some can undergo malnourishment, which is the leading cause of iron deficiency anemia.


How Fast Can Hemoglobin Level Drop?

Hemoglobin can live up to 120 days in the human body. If the bone marrow, which produces the red blood cells, stops producing it, the levels of hemoglobin can drop only one percent per day. Any faster depletion of hemoglobin can be due to blood loss.


Are 8.4 Grams per Deciliter of Hemoglobin Low?

Yes, 8.4 grams per deciliter of hemoglobin are low levels. Low hemoglobin levels for men are below 13.2 grams per deciliter, and in women, it is below 11.6 grams per deciliter. 


What Are the Lowest Safe Levels of Hemoglobin?

The lowest level of hemoglobin, which can be withheld for blood transfusion, is above 7 grams per deciliter of hemoglobin. If the levels are 7 and below, it is considered a critically ill state which requires an immediate blood transfusion.


Which Fruits Can Increase the Levels of Hemoglobin?

Fruits that are rich in vitamin C, such as oranges, strawberries, sweet lime, lemons, berries, grapefruits, and gooseberries, can increase hemoglobin levels. Other fruits such as dried figs, apricots, watermelons, pomegranates, bananas, apples, and grapes contain iron and calcium, which can also help in increasing hemoglobin levels.


Can Hemoglobin Levels of 5 Grams per Deciliter Cause Critical Issues?

Yes, 5 grams per deciliter of hemoglobin is dangerous and can cause a severe life-threatening condition, which can lead to severe weakness, pale skin, swollen hands and feet, irregular heartbeat, and heart failure.


Can Drinking Water Increase the Levels of Hemoglobin?

Yes, drinking water can improve hemoglobin levels to some extent. But being hydrated is important because dehydration can cause a change in the size of red blood cells, which can lead to low hemoglobin levels. 
Dr. Rajesh Gulati
Dr. Rajesh Gulati

Family Physician


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