How to order reticulocyte (reticulocyte count) laboratory tests?

From the Guidelines

To order reticulocyte labs, request a "reticulocyte count" or "reticulocyte panel" on your laboratory requisition form, as this test is crucial for evaluating anemia and monitoring bone marrow response to treatment, as indicated by the most recent study 1. When ordering, specify whether you want just the reticulocyte count or the complete reticulocyte panel, which includes the reticulocyte count, reticulocyte percentage, and reticulocyte production index (RPI). The reticulocyte count measures immature red blood cells released from bone marrow, providing valuable information about erythropoietic activity. This test is particularly useful when evaluating anemia, monitoring bone marrow response to treatment, or assessing recovery from blood loss. Results are typically available within 24-48 hours. When interpreting results, remember that normal reticulocyte values range from 0.5-2.5% of total red blood cells or 25,000-75,000/μL in absolute count, though reference ranges may vary slightly between laboratories. Some key points to consider when ordering reticulocyte labs include:

• The test requires a standard blood draw collected in an EDTA (purple-top) tube, with approximately 3-5 mL of blood needed.
• No special patient preparation is required, and the test can be performed at any time of day.
• The reticulocyte count can help distinguish between different types of anemia, such as iron deficiency anemia, vitamin B12 or folate deficiency, and anemia of chronic disease, as discussed in 1 and 1.
• The test can also be used to monitor the response to treatment, such as iron supplementation or erythropoietin therapy, as mentioned in 1 and 1.
• In addition to the reticulocyte count, other laboratory tests such as serum iron, total iron binding capacity (TIBC), and ferritin may be useful in evaluating iron deficiency and monitoring the response to treatment, as discussed in 1 and 1.

From the Research

Reticulocyte Lab Ordering

To order reticulocyte labs, consider the following steps:

• Determine the purpose of the test, such as diagnosing iron deficiency anemia or monitoring erythropoietic function 2, 3
• Choose the appropriate test, such as complete blood count (CBC) with reticulocyte hemoglobin content (CHr) or reticulocyte count 2, 4
• Consider the advantages and limitations of each test, including sensitivity, specificity, and potential interference from inflammation or other conditions 2
• Be aware that there is no standardized cutoff point for CHr, and different researchers may use varying cutoff values 2

Diagnostic Applications

Reticulocyte labs can be used for:

• Diagnosing iron deficiency and iron deficiency anemia 2, 3
• Monitoring response to iron therapy 2, 3
• Evaluating erythropoietic function 4, 3
• Screening for iron deficiency 2
• Diagnosing functional iron deficiency anemia in acute or chronic diseases or inflammation 2

Test Interpretation

When interpreting reticulocyte lab results, consider the following:

• CHr has a moderate sensitivity and specificity for diagnosing iron deficiency 2
• Reticulocyte count can serve as a useful screen for hemolysis or blood loss 4
• Reticulocyte indices, such as volume, hemoglobin concentration, and content, can provide additional information on erythropoietic function 3