Red Blood Cell Indices

Red Blood Cell Indices (RBC Indices) are a group of blood tests and parameters that are driven from these test results their purpose is to study how healthy are the Red Blood Cells of a patient in order to classify anemia and better understand its causes. Anemia is not one kind and it may be caused by several causes, some types of anemia are associated with low Red Blood Cell Count and have nothing to do with conditions that cause the production of abnormal Red Blood Cells. Other types of anemia are associated with abnormalities in the color or size of Red Blood Cells.

 

Red Blood Cell Indices are ordered routinely as a part of Complete Blood Count (CBC). Complete Blood Count is a blood test performed using automated cell counting machines. Before using these machines, a blood smear is tested under the microscope to examine the color and size of Red Blood Cells. Studying a blood smear under the microscope was a long and exhausting process that automated cell counting reduced its demand by physicians.

 

Neither CBC nor RBC Indices replaces the blood smear test. Blood smear test is still used to examine the shape of RBCs and White Blood Cells. Blood Smears are still used even to count RBCs in conditions which may cause the counting machines to make wrong results.

 

 

 

A List of Red Blood Cell Indices

 

 

 

Using Red Blood Cell Indices in Classifying Anemia.

RBC Indices are used as a fast and effective method to classify Anemia. Different types of Anemia may show the same symptoms. However, anemia can be caused caused by different causes and those causes would have different impacts on Red Blood Cells count, color, or size. The following is a listing that shows different types of anemia and how are Red Blood Cell Indices are used to classify them.

 

 

Normocytic, Normochromic Anemia

Red Blood Cells in Normocytic Normochromic Anemia have normal average cell size (Normocytic) and normal cell color (Normochromic).  Values Red Blood Cell Indices of Normocytic Normochromic Anemia will be like:

 

 

 

White Red Blood Cells may look normal in Normocytic Normochromic Anemia. High variations in Red Blood Cell size can be detected.  Normocytic Normochromic Anemia include:

 

  • Early stages of Iron Deficiency Anemia: At these early stages, iron deficiency starts causing a small number of Red Blood Cells to have smaller size compared to normal RBCs. Even though the patient is suffering from Iron Deficiency Anemia, the majority of RBCs will not be affected by iron deficiency at those early stages which causes the patient’s to have Hematocrit and MCV levels laying in the normal range. However, the RDW Test will show high variation in RBC sizes since some of the cells have a small size and the others have a normal size.
  • Chronic Illness including Sepsis and Tumor.
  • Acute Blood Loss causes the Red Blood Cell count in human blood to decrease and it doesn’t affect the Red Blood Cells size, color or shape.
  • Aplastic Anemia (Chloramphenicol Toxicosis for example)
  • Acquired Hemolytic Anemia: This type of anemia is associated with lysis of Red Blood Cells which causes a reduction in Red Blood Cell count. This usually occur as a result of a Prosthetic Cardiac Valve break down the cells mechanically during blood circulation.

 

 

Microcytic, Hypochromic Anemia

Microcytic Hypochromic Anemia causes Red Blood Cells to have abnormally small size (Microcytic) and pale or less colored look (Hypochromic) insufficient production of Hemoglobin. Red Blood Cell Indices of Microcytic Hypochromic Anemia will be like:

 

  • Mean Corpuscular Volume: Low.
  • Mean Corpuscular Hemoglobin: Normal or Slightly Low.
  • Mean Corpuscular Hemoglobin Concentration: Low.
  • Red Blood Cell Distribution Width: Normal or High.

 

Examples of Microcytic Hypochomic Anemia include:

 

  • Iron Deficiency Anemia.
  • Thalassemia.
  • Lead poisoning.

 

 

Microcytic, Normochromic Anemia

 

Microcytic Normochromic Anemia causes Red Blood Cells to have a smaller size than normal with a normal red color. Microcytic Normochromic RBCs are found in patients who have Renal Disease because of the loss of Erythropoietin (A kidney produced hormone that causes controls the production of RBCs). Microcytic, Normochromic Anemia causes RBC Indecies to have the following values:

 

  • Mean Corpuscular Volume: Low.
  • Mean Corpuscular Hemoglobin: Low.
  • Mean Corpuscular Hemoglobin Concentration: Normal.
  • Red Blood Cell Distribution Width (RDW): Normal.

Macrocytic, Normochromic Anemia

Red Blood Cells will have a larger than normal size (Macrocytic) and a normal red color (Normochromic) if the patient has Macrocytic Normochromic Anemia. Red Blood Cell Indices will be as  the following:

 

  • Mean Corpuscular Volume: High.
  • Mean Corpuscular Hemoglobin: High.
  • Mean Corpuscular Hemoglobin Concentration: Normal.
  • Red Blood Cell Distribution Width (RDW): Normal.

 

The following is a list of the causes of producing abnormally large red blood cells which leads to high MCV and MCH indecies:

 

  • Vitamin B12 or Folic Acid Deficiency.
  • Hydantoin Ingestion.
  • Chemotherapy.
  • Some Myelodysplastic Syndromes.
  • Myeloid Leukemia.
  • Ethanol Toxicity.
  • Thyroid Dysfunction.