What is the interpretation of an elevated Red Cell Distribution Width-Coefficient of Variation (RDW-CV) at 44.3?

From the Guidelines

An RDW-CV of 44.3% is significantly elevated and warrants prompt medical evaluation to rule out underlying conditions such as iron deficiency anemia, vitamin B12 or folate deficiency, hemolytic anemia, or certain chronic diseases. This high value indicates substantial variation in the size of red blood cells (anisocytosis), which can disrupt normal oxygen delivery to tissues. According to the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1, iron deficiency can be indicated by reduced mean cell Hb (MCH) and mean cell volume (MCV), although these markers may lose sensitivity in the presence of chronic disease or other conditions. The European Consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1 also highlights the importance of considering reticulocyte count, serum ferritin, and transferrin saturation in the diagnosis of iron deficiency anaemia. Given the elevated RDW-CV, the next steps should include:

• A complete blood count to assess other blood parameters
• Iron studies, including serum ferritin and transferrin saturation
• Vitamin B12 and folate levels
• Possibly a peripheral blood smear examination It is essential to interpret these results in the context of the patient's complete clinical picture, symptoms, and additional laboratory tests under medical supervision, as self-diagnosis or treatment based on a single value can be misleading.

From the Research

Interpretation of RDW-CV at 44.3

• RDW-CV is a measure of the variation in red blood cell size, with higher values indicating a greater variation in size.
• A value of 44.3 is considered elevated, as seen in a study where a cutoff value of 44.55 was used to predict pulmonary embolism in COPD patients 2.
• Elevated RDW-CV values have been associated with various conditions, including cardiovascular disease, cancer, and chronic obstructive pulmonary disease (COPD) 3, 4, 5, 2.
• In the context of COPD patients with pulmonary embolism, an RDW-CV value of 44.3 may indicate an increased risk of pulmonary embolism, as higher RDW-SD and RDW-CV values were found in COPD patients with PE compared to those without PE 2.
• The predictive value of RDW-CV for cardiovascular risk assessment is still being researched, but it may be a useful marker for identifying patients at higher risk of adverse outcomes 3, 4, 5.

Association with Mortality and Morbidity

• Elevated RDW-CV values have been associated with increased mortality and morbidity in various studies, including all-cause mortality, cancer mortality, cardiovascular mortality, and respiratory disease mortality 4, 5.
• The relationship between RDW-CV and mortality is thought to be due to the association between RDW-CV and underlying chronic diseases, as well as the potential for RDW-CV to reflect systemic inflammation and oxidative stress 4, 5.

Clinical Implications

• An RDW-CV value of 44.3 may indicate the need for further evaluation and monitoring for underlying conditions, such as cardiovascular disease or COPD 3, 4, 5, 2.
• The use of RDW-CV as a predictive marker for pulmonary embolism in COPD patients may be useful in clinical practice, particularly when combined with other biomarkers such as D-Dimer 2.