Significance on the red blood cell distribution width in microcytosis and hypochromia anaemia

Objective To study the relationship of red blood cell distribution width(RDW)-CV and RDW-SD,and know the clinical application value of RDW-SD.Methods The reference intervals of RDW-CV and RDW-SD were established firstly according to the Clinical and Laboratory Standards Institute(CLSI) Document C28-A2,and the distributions among healthy subjects were analyzed.The RDW-CV and RDW-SD of 121 random samples,109 samples from thalassanemia patients and 25 samples from iron deficiency anaemia patients were determined and analyzed according to the reference intervals.Results The distribution of RDW-CV in healthy subjects nearly conformed to normal distribution,and that of RDW-SD was skewed distribution.The trend of increasing or decreasing were not the same in RDW-CV and RDW-SD.When the samples′RDW-CV increased or were normal,their RDW-SD could increase,be normal or decrease.When the samples′ RDW-CV decreased,their RDW-SD could be normal or decrease.Their accordance was 80.0% in random samples.The averages of RDW-CV and RDW-SD in iron deficiency anaemia patients were higher than those in thalassanemia patients,but the ranges of RDW-CV and RDW-SD in thalassanemia patients were wider than those in iron deficiency anaemia patients,and included the distribution of iron deficiency anaemia patients.Most of the RDW-CV results of thalassanemia patients and iron deficiency anaemia patients were higher than the reference interval upper limit,and none showed lower than the reference interval lower limit.The RDW-SD in thalassanemia patients could usually decrease or increase and be normal,which was inverse to the RDW-CV,and none decreased among iron deficiency anaemia patients.Conclusions It can reflect the heterogeneity of red blood cell more roundly by determining the RDW-CV and RDW-SD simultaneously,which has significant value in the diagnosis of thalassanemia and iron deficiency anaemia.