Hemoglobin Levels : testing, low or high level and clinical significance

Hemoglobin is a protein in your red blood cells that carries oxygen. The hemoglobin test is a common test that measures the amount of hemoglobin in your blood and is almost always done as part of a complete blood count (CBC).



◉ Structure of hemoglobin

Hemoglobin is a tetrameric protein, meaning it is made up of four subunits, each with a polypeptide chain and a heme group that combine to form a functional structure .

◉ Types

There are different types of hemoglobin that differ in their molecular composition. Hemoglobin electrophoresis is a test that measures the different types of hemoglobin in the blood.

The most commonly encountered types are:

Note: There are many other hemoglobin variants and abnormalities (hemoglobinopathy) that may have specific medical implications.

◉ Hemoglobin function

◉ Hemoglobin assay

The monitoring and measurement of the hemoglobin level is usually done through laboratory blood tests called Complete Blood Count (CBC). The value of the result is usually expressed in Grams per deciliter (g/dL)

You do not need to be fasting for the exam. A healthcare professional will take a blood sample from your vein and send it to the lab where it will be tested.

◉ Normal level of hemoglobin in the blood

The amount of normal hemoglobin is included:

Table 1: Hemoglobin normal value
CategoryHgb level, in grams per deciliter (g/dL)
Infants11-18
Toddlers11.5-16.5
Adult males13-16.5
Adult females (non-pregnant)12-6
Adult women (pregnant)11-16

Note: It is important to consider the specific reference values of the laboratory where the test was performed when interpreting hemoglobin results.


◉ Factors Affecting Hemoglobin Levels

Various factors influence hemoglobin levels in the body, including:

◉ Causes

2- Causes of low hemoglobin :

2- Causes of High Hemoglobin :

If a hemoglobin test shows a higher than normal level, there are several potential causes:

◉ Symptoms

1- What are the symptoms of low hemoglobin? :

2- High Hemoglobin Symptoms :

If your hemoglobin level is higher than usual, you may experience the following symptoms:

◉ Additional tests

To make an accurate diagnosis and implement appropriate treatment in the event of abnormally low hemoglobin levels, the healthcare professional may request several other complementary tests

◉ Treatment

The treatment depends on the hemoglobin level in the blood, the cause and the symptoms that the patient has:

◉ Conclusion

Hemoglobin is an essential protein responsible for transporting oxygen in the body. Its ability to bind and release oxygen ensures the supply of oxygen to all tissues and organs, promoting their proper functioning.

Regular monitoring of hemoglobin levels and understanding the factors influencing its levels are essential for diagnosing and managing various health conditions.


Reference

  1. Alain J. Marengo-Rowe - Structure-function relations of human hemoglobins
  2. Molecule of the Month: Hemoglobin
  3. What is Haemoglobin?
  4. Biochemistry Den- Hemoglobin: Structure, Function and its Properties
  5. Lynne Eldridge, MD - What Is the Function of Hemoglobin?
  6. Hemoglobin electrophoresis
  7. medlineplus - Hemoglobin Electrophoresis