Calculating the red cell distribution width (RDW) may be useful in differentiating neurological and cerebrovascular disease, according to the results of a recent series of papers.
RDW measures the range of variation in RBC volume, with width referring to the distribution width of the volume curve. RDW values may be used to differentiate different conditions, such as iron deficiency anemia (increased RDW, low mean corpuscular volume [MCV]), folate or vitamin B12 deficiency anemia (increased RDW, elevated MCV), and recent hemorrhage (increased RDW, normal MCV).
A new study suggests that RDW can be employed to distinguish ischemic stroke from stroke mimics, such as MS or epilepsy, in younger patients (Demir et al. Arch Med Sci 2015;11:958-963). The retrospective study determined the mean RDW values of 236 young patients with stroke, MS and epilepsy. Mean RDW values were significantly higher in stroke cases (14.9) compared to MS (13.3) or epilepsy (13.4). The sensitivity and specificity were 73.7% and 87.9% with an RDW cut-off value of 14.05; the positive predictive value was 6.1.
The same group has suggested that RDW can be used to help in the diagnosis of cerebral venous sinus thrombosis in patients presenting with headache (Demir et al. Clin Appl Thromb Hemost 2015;21:354-358). The RDW was significantly higher in CVST compared to primary headache (15.3 vs. 13.3). The proposed cut-off value was 14.1% (sensitivity 91.9%, specificity 99%, positive predictive value 92.8).
An analysis of data from the Malmo Diet and Cancer Study found that the incidences of total stroke and cerebral infarction were higher in individuals with high RDW values (Soderholm et al. PLoS One 2015;10:e0124957; free full text at www.ncbi.nlm.nih.gov/pmc/articles/PMC4423855/pdf/pone.0124957.pdf). Comparing the highest versus lowest quartile of RDW values, the adjusted hazard ratios for total stroke and cerebral infarction were 1.31 and 1.32, respectively. There was no significant association between RDW and the incidence of intracerebral or subarachnoid hemorrhage.