To the Editor: We have read the article entitled, "Association between Red Blood Cell Distribution Width (RDW) and Coronary Artery Calcification in Patients Undergoing 64-Multidetector Computed Tomography" by Gurel et al.1) They aimed to determine whether the RDW measures are associated with the coronary artery calcification score (CACS) in patients who did not present with obvious coronary artery disease (CAD). They concluded that the RDW is an independent predictor of the CACS, suggesting that it might be a useful marker for predicting CAD. This study provides important information on this clinically relevant condition. Inflammation is a significant feature of the arteriosclerotic process, and some novel inflammatory indicators have been shown in any stage of the arteriosclerotic process.2) Complete blood count has several routinely available markers that can indicate inflammatory status. At present, many studies concluded that parameters like neutrophil-lymphocyte ratio, RDW, mean platelet volume levels were higher in patients with inflammatory diseases compared with controls.2),3),4) RDW indicates the variability in the size of circulating erythrocytes and is expressed as the coefficient of variation of the erythrocyte volume. Recently, a number of studies have reported that RDW levels, which may be related to subclinical inflammation, are increased in many inflammatory diseases.5) Furthermore, some studies reported that RDW levels were independently associated with mortality in both the general population and in patients with certain diseases. However, some conditions should be considered when RDW levels are evaluated. RDW can reflect ethnicity, neurohumoral activation, renal dysfunction, thyroid disease, nutritional deficiencies (i.e. iron, vitamin B12, and folic acid), bone marrow dysfunction, inflammatory diseases, chronic or acute systemic inflammation6) and use of some drugs.7) The correlation with bilirubin could also be due to hepatic dysfunction and excessive alcohol intake, resulting in macrocytosis and increased RDW. Also, it would be better if the authors might define how much time they specified on measuring RDW levels, because delaying blood sampling can lead to abnormal results in RDW assessments.8) In conclusion, we strongly believe that the findings obtained from the current study will lead to further studies assessing the relationship between RDW and CAD. Finally, not only RDW but also mean platelet volume, neutrophil lymphocyte ratio, platelet distribution width, RDW- lymphocyte ratio are easy methods for predicting cardiovascular disease in patients.9) These markers might be useful in clinical practice.10)