Reference Intervals of Reticulocyte Parameters using ADVIA 120

Background : Reticulocytes are circulating immature erythrocytes at the stage just before maturity of the erythrocyte. The maturation time for reticulocyte is 3.5 to 4 days including one day of circulation; therefore, circulating reticulocytes represent marrow erythropoietic activity that is faster than any other hematologic item. To take advantage of reticulocyte parameters, we should first identify the reference ranges and understand the basic information of the parameters. Methods : We selected healthy subjects with normal Hb, WBC and platelet count in an annual health surveillance of employees of Boramae Hospital. In total, 285 subjects (74 males and 211 females) were analyzed using ADVIA 120. The analyzed parameters were reticulocyte count, reticulocyte indices and reticulocyte maturity indices. The reference intervals were obtained with the central 95% of the distribution. Results : The reference intervals: reticulocyte count 41.8-121.3 (/ L), 0.9-2.5 (%); MFR (middle fluorescence reticulocyte) 1.3-9.8 (%); HFR (high fluorescence reticulocyte) 0-1.5%; MCVr (MCV for reticulocyte) 100.6-112.7 (fL); CHCMr (cellular hemoglobin concentration mean for reticulocyte) 29.5-33 (g/dL); RDWr 8-10.5 (%); CHr (cellular hemoglobin content for reticulocyte) 30.8-35.5 (pg). According to the maturation of reticulocytes, the volume decreased 20%, CHCM increased 11%, and CH decreased 6%. Conclusions : The reticulocyte parameters are available for real-time assessment of marrow erythropoietic activity and clinically they will help in the diagnosis and treatment of various anemias.