Red Cell Distribution Width, or RDW, is a measurement often included as part of a complete blood count (CBC) test. RDW specifically offers information about the characteristics of your red blood cells, which carry oxygen throughout your body.
What RDW Measures
RDW quantifies the variation in the size and volume of your red blood cells, a condition known as anisocytosis. When RDW is within the typical range, it indicates that your red blood cells are relatively uniform in size. A normal RDW range generally falls between 11.5% and 14.5%. This measurement helps healthcare providers assess the consistency of red blood cell production and maturation.
The body continuously produces new red blood cells, and their size can be affected by various factors. An RDW value outside the normal range suggests that there is a greater than average variation in the size of these cells. Understanding this variation helps evaluate red blood cell health. This metric helps differentiate between certain types of anemia or other blood disorders.
Interpreting Low RDW Levels
A low RDW value is uncommon and indicates your red blood cells are exceptionally uniform in size. This finding, especially when it falls within or just slightly below the established normal range, is rarely considered a significant clinical concern on its own. Unlike a high RDW, which frequently signals underlying conditions like various forms of anemia due to a wide range of cell sizes, a low RDW does not typically point to a dangerous health issue.
A low RDW is not indicative of a specific disease and is a benign finding. While certain conditions, such as aplastic anemia or some forms of thalassemia, might sometimes be associated with a low RDW, it is important to understand that other blood parameters and clinical symptoms are the primary indicators for these diagnoses. The low RDW in these instances would be a secondary observation rather than the main diagnostic clue. Therefore, a “dangerously low” RDW is a misconception, as the value itself does not pose a direct threat or signify a severe underlying problem.
When to Discuss Your Results
RDW is merely one component of a complete blood count, and its interpretation should always occur in the broader context of other blood parameters. Values such as mean corpuscular volume (MCV), hemoglobin levels, and the total red blood cell count provide a more comprehensive picture of your blood health. A healthcare professional considers all these factors together, alongside your medical history and any symptoms you might be experiencing.
If you have received blood test results, including an RDW value, and have any questions or concerns, it is always advisable to discuss them with your doctor. Attempting to self-diagnose based on a single laboratory value is not recommended, as it can lead to misunderstandings and unnecessary worry. Your physician can accurately interpret your results and determine if any further investigation or action is needed.