What is what level of rdw is dangerous?

There isn't a single "dangerous" RDW (red blood cell distribution width) value that applies universally. RDW is an indicator of the variation in the size of red blood cells, and a high RDW suggests anisocytosis (variation in red blood cell size). A high RDW in conjunction with other findings can be indicative of several conditions, making it dangerous only when it's part of a larger picture suggesting a serious underlying health problem.

Here's a breakdown:

  • Normal RDW: Generally considered to be between 11.5% and 14.5%. However, reference ranges can vary slightly depending on the laboratory and the method used.

  • Elevated RDW: An RDW above the normal range indicates anisocytosis. This alone isn't necessarily dangerous, but it warrants further investigation to determine the cause. A high RDW is often associated with conditions like:

    • Iron deficiency anemia: This is a very common cause of elevated RDW. Iron is crucial for red blood cell production, and a deficiency leads to smaller, varied red blood cells.
    • Vitamin B12 deficiency anemia: Similar to iron deficiency, it impacts red blood cell production and size.
    • Folate deficiency anemia: Another nutritional deficiency affecting red blood cell production.
    • Thalassemia: A group of inherited blood disorders affecting hemoglobin production.
    • Myelodysplastic syndromes (MDS): A group of cancers affecting blood cell production in the bone marrow. This is a more serious condition where a high RDW could be a significant warning sign.
    • Chronic diseases: Conditions like chronic kidney disease or inflammation can also lead to an elevated RDW.
  • The Danger: The "danger" isn't solely in the RDW number itself, but in the underlying condition it might indicate. For example, an elevated RDW in the context of fatigue, pallor, and low hemoglobin would raise serious concerns about anemia, potentially requiring treatment. However, a slightly elevated RDW in an otherwise healthy individual might not be clinically significant.

In short: A high RDW is a warning flag, not a diagnosis. It needs to be interpreted in the context of a patient's complete blood count (CBC) results, symptoms, and medical history. A doctor will use this information to determine the cause of the elevated RDW and recommend appropriate testing and treatment if necessary. Don't try to interpret an isolated RDW value; it needs to be evaluated within the larger picture of a person's health.