This page helps you to understand blood test results for Red Cell Count and gives you the reference range to determine if your lab test results mean that you have a high, low or normal Red Cell Count.
We outline the risk factors associated with both raised and lower Red Cell Count.
Reference Ranges for Red Cell Count in men (please sign up to see ranges for women):
|US Conventional Units||x10E6/uL = x10^12/L||4.32-5.72||<4.32 or > 5.72|
|Standard International Units||x10E6/uL = x10^12/L||4.32-5.72||<4.32 or > 5.72|
What are Red Blood Cells
Red blood cells (RBCs), also called erythrocytes, are cells that circulate in the blood and carry oxygen throughout the body. The RBC count totals the number of red blood cells that are present in a person’s sample of blood. It is one test among several that is included in a complete blood count (CBC) and is often used in the general evaluation of a person’s health.
Blood is made up of a few different types of cells suspended in fluid called plasma. In addition to RBCs, there are white blood cells (WBCs) and platelets. These cells are produced in the bone marrow and are released into the bloodstream as they mature .
Function of Red Blood cells
RBCs typically make up about 40% of the blood volume. RBCs contain hemoglobin, a protein that binds to oxygen and enables RBCs to carry oxygen from the lungs to the tissues and organs of the body. RBCs also help transport a small portion of carbon dioxide, a waste product of cell metabolism, from those tissues and organs back to the lungs where it is expelled.
RBCs have a typical lifespan of about 120 days and are continuously renewed and replaced as they age and degrade or are lost through bleeding. A relatively stable number of RBCs is maintained in the circulation by increasing or decreasing the rate of production by the bone marrow .
Risk factors associated Red Cell Count
The typical lifespan of an RBC is 120 days; thus the bone marrow must continually produce new RBCs to replace those that age and degrade or are lost through bleeding. There are a number of conditions that can affect the production of new RBCs and/or their lifespan, in addition to those conditions that may result in significant bleeding. These conditions may lead to a rise or drop in the RBC count.
Changes in the RBC count usually mirror changes in the hematocrit and hemoglobin level. When the values of the RBC count, hematocrit, and hemoglobin decrease below the established reference interval, the person is said to be anemic. When the RBC and hemoglobin values increase above the normal range, the person is said to be polycythemic.
If the liquid component of the blood (plasma) is decreased, as in dehydration, the red blood cell count increases. This is due to the red blood cells becoming more concentrated. The actual number of red blood cells stays the same.
Too few RBCs can affect the amount of oxygen reaching the tissues, while too many RBCs can cause decreased blood flow and related problems.
While an RBC count can be used to detect a problem with red blood cell production and/or lifespan, it cannot determine the underlying cause .
Notable variations by demographic group
- Males tend to have slightly higher concentrations of red blood cells, higher haemoglobin and haematocrit, and there are separate reference ranges for males and females.
- In pregnancy, there is an increase in plasma volume of the blood in order to help supply oxygen and nutrients to mother and baby and therefore women who are pregnant commonly have lower results for red cell count, hemoglobin and haematocrit.