Reticulocyte Count

The reticulocyte count is a medical laboratory test that measures the number of reticulocytes, which are immature red blood cells, in the bloodstream.

Purpose

The primary purpose of a reticulocyte count is to assess the production of red blood cells by the bone marrow and to diagnose and monitor various blood disorders, such as anemia, polycythemia, and bone marrow failure.

Procedure

To perform a reticulocyte count, a blood sample is typically drawn from a vein in the arm. The sample is then sent to a laboratory for analysis.

Staining Techniques

In the laboratory, the blood sample is stained with a supravital dye, such as new methylene blue or brilliant cresyl blue, which selectively stains the RNA in reticulocytes. This allows the reticulocytes to be distinguished from mature red blood cells.

Interpretation

The results of a reticulocyte count are usually expressed as a percentage of the total number of red blood cells. A normal reticulocyte count is typically between 0.5% and 1.5%. An increased reticulocyte count may indicate:

• Response to anemia treatment
• Bone marrow recovery after chemotherapy or radiation therapy
• Hemolytic anemia, where red blood cells are being destroyed faster than they can be produced

A decreased reticulocyte count may indicate:

• Bone marrow failure or aplastic anemia
• Anemia of chronic disease
• Iron deficiency anemia

Clinical Significance

The reticulocyte count is a valuable tool in the diagnosis and management of various blood disorders. It can help healthcare providers:

• Evaluate the severity of anemia
• Monitor response to treatment
• Detect bone marrow dysfunction or failure

Limitations

The reticulocyte count has some limitations, including:

• Poor correlation with the severity of anemia in certain cases
• Inaccurate results if the blood sample is not handled or stained properly
• Interference from other medical conditions or medications

Reference Ranges

The reference ranges for reticulocyte count may vary depending on the laboratory and the individual's age, sex, and medical condition. In general, the following reference ranges are used:

• Newborns: 2-6%
• Infants: 1-4%
• Children: 0.5-1.5%
• Adults: 0.5-1.5%