Application value of reticulocyte parameters in chemotheraphy of acute leukemia / 国际检验医学杂志

Objective To study the clinical significance of reticulocyte parameters change before and after chemotheraphy in acute leukemia.Methods Thirty-two chemotherapeutic patients suffered from acute leukemia were improved after chemotherapy.The percentage of reticulocyte(RET%),reticulocyte absolute value(RET#),low fluorescent reticulocyte percentage(LFR),middle fluorescent reticulocyte percentage(MRF),high fluorescent reticulocyte percentage(HFR),white blood cells(WBC) and absolute neutrophils count (ANC) and immature reticulocyte fraction(IRF) were detected by using the Sysmex 2000 automatic blood cell analyzer.Results IRF,MFR and HFR after chemotherapy in the patients with leukemia were always declined,reached the lowest on 7 d of chemotherapy,began to recover on 14 d after chemotherapy,and recovered to the level before chemotherapy on 21 d of chemotherapy.LFR began to increase on 7 d of chemotherapy,and began to decrease on 14 d of chemotherapy.WBC and RET# were always decreased on 7,14 d of chemotherapy,and began to recover on 21 d of chemotherapy.Conclusion IRF,MFR,HFR and LFR are the sensitive indicators reflecting the bone marrow recovery and are earlier than WBC and RET# by 7 d.

Determination of reference ranges for immature platelet and reticulocyte fractions and reticulocyte hemoglobin equivalent

ABSTRACT Introduction: The immature platelet and immature reticulocyte fractions represent the ratios of platelets and reticulocytes recently released into the circulation and thus with higher RNA content. They are considered early indicators of bone marrow recovery. Objective: The aim of this study was to determine the reference ranges for the immature platelet and reticulocyte fractions of hematologically normal individuals in a university hospital. Methods: Venous blood samples collected in ethylenediaminetetraacetic acid K3 were analyzed using a Sysmex XE-5000™ analyzer. Individuals with platelet and reticulocyte counts within the reference ranges, and a blood count within the laboratory's screening criteria were included. Individuals with clinical conditions that could affect hematological results were excluded. The immature platelet fraction, high, medium and low fluorescence reticulocyte fractions and reticulocyte hemoglobin equivalent were evaluated. The reference ranges were determined according to the recommendations of the International Federation of Clinical Chemistry. Results: One hundred and thirty-two outpatients were evaluated. The mean age was 44 years (range: 13-80 years), 72 (54.5%) were women treated in a university hospital. The mean platelet count was 250.8 × 109/L and the mean reticulocyte count was 0.052 × 109/L. The following reference ranges were obtained: immature reticulocyte fraction 1.6-12.1%, the high, medium and low fluorescence reticulocyte fractions were 0.0-1.7%, 1.6-11.0% and 87.9-98.4%, respectively, the reticulocyte hemoglobin equivalent was 30.0-37.6% and immature platelet fraction was 0.8-5.6%. There was a statistically significant difference (p-value = 0.006) between genders in respect to the immature platelet fraction with 0.8-4.7% for females and 0.7-6.1% for males. The immature reticulocyte fraction was directly correlated with the reticulocyte count. Conclusion: Determining the reference range is critical to the introduction of a new parameter. The reference ranges obtained herein corroborate those reported in previous publications and will contribute to the clinical and laboratory application of the indices.

El conteo automático de reticulocitos: una herramienta de uso diagnóstico, clínico e investigativo / Automated reticulocyte count: a tool for diagnostic, clinical and research use

Se revisan los antecedentes históricos del conteo de reticulocitos como determinación indispensable en el laboratorio de hematología para la evaluación de la actividad eritropoyética durante la clasificación, diagnóstico y monitoreo de la respuesta terapéutica en distintos trastornos y situaciones clínicas, principalmente en casos de anemias. Se describe el tránsito del tradicional método de conteo de reticulocitos manual al método automatizado y la integración de los parámetros reticulocitarios al hemograma automatizado actual; además, se analizan las desventajas del método de recuento manual y las ventajas del método automatizado, así como los principios de detección en que se basa el conteo electrónico de reticulocitos. Con relación a los parámetros reticulocitarios, se describe su medición, cálculo y unidades de medida; también se resalta la importancia de la fracción de reticulocitos inmaduros y del contenido de hemoglobina reticulocitaria como variables de mayor uso clínico e investigativo en la evaluación de la respuesta medular ante diversos trastornos clínicos y protocolos terapéuticos. Por último, se alude a la necesidad del conocimiento y empleo de las variables reticulocitarias en la práctica clínica de rutina por parte de los clínicos y especialistas en hematología.

The historical background of reticulocyte count is reviewed as an essential determination in the laboratory of hematology for the evaluation of erythropoietic activity during classification, diagnosis and monitoring of therapeutic response of different conditions and clinical situations are also reviewed, especially in anemia The transition from traditional manual reticulocyte counting method to automated method and integration of the reticulocyte parameters to current automated complete blood count are described. The disadvantages of manual method and the advantages of automated methods are cited, as well as detection principles in which electronic reticulocyte count is based. Regarding reticulocyte parameters, measurement, calculation and units are described. The importance of immature reticulocyte fraction and reticulocyte hemoglobin content as variables most clinical and research use in evaluating bone marrow response to various clinical disorders and therapeutic protocols are highlighted. Finally, the need for knowledge and use of reticulocyte variables in routine clinical practice by clinicians and hematologist is referred.

The comparison of reticulocyte parameters on the XN-1000 and LH780 hematology analyzer / 国际检验医学杂志

Objective To analyze the comparability and correlation of reticulocyte parameters on the Beckman‐Coulter LH780 (LH780)and Sysmex XN‐1000(XN‐1000)hematology analyzers .Methods 80 blood samples were measured by the two instru‐ments ,the RBC count ,percentage of Ret(Ret% ) ,Ret value(Ret#)and immature reticulocyte fraction(IRF) were analyzed ,and the correlation of Ret% ,Ret# and IRF between two instruments were also analysed .The correlation between percentage of high laser reticulocyte(HLR% ) of LH780 and percentage of middle fluorescent reticulogyte(MFR% )+percentage of high fluorescent reticu‐locyte(HFR% ) of XN‐1000 were compared using two calculation methods of each instrument ,and the application value of HLR%were analysed .Results No significant differences were founded in RBC count ,Ret% ,and Ret# between the two instruments(P>0 .05) ,while there was statistical difference in IRF between the the two instruments (P<0 .05) .The relative deviation coincidence rate of RBC count was 97 .5% ,the correlation coefficent (r) of Ret% ,Ret# and IRF were 0 .912 ,0 .895 and 0 .666 respectively . There were statistical differences and correlations between HLR% and MFR% + HFR% when using calculation method of XN‐1000 and LH780 respectively(r were 0 .666 and 0 .767 respectively ,P<0 .05) .Conclusion The RBC count could meet the matc‐hing requirement ,and the Ret% and Ret # may be highly correlated on the two instruments .While the reference range of IRF should be established in each instrument .

Immature Reticulocyte Fraction in Guiding Stem Cell Harvest in Autologous Peripheral Blood Stem Cell Transplant

Peripheral blood (PB) CD34+ cells enumeration is currently the most reliable method to guide the timing of stem cell harvest. However, its usage is restricted by being technically challenging, costly, and time-consuming. Immature reticulocyte fraction (IRF) determination, which is simpler and cheaper and has a faster turn-around time, has been proposed for a similar purpose. The purpose of this study is to evaluate the value of IRF in guiding stem cell harvest and examine the correlation between IRF and PB CD34+ cells count. Daily pre-harvest tests, i.e. PB CD34+ cells and IRF from 21 patients scheduled for autologous PBSC transplant were assessed. Stem cells harvests were commenced when the PB CD34+ cell count were more than 10 cell/ul. A total of 205 pre-harvest tests were analysed. Following stem cell mobilisations, both the IRF and PB CD 34+ cell counts rose with a variable pattern. In this study, we observed that the IRF peaks preceded the PB CD34+ count by 2 days. On the day of stem cell harvest, all the peak IRF values were >0.3. The PB CD34+ cell counts correlated with the harvested stem cell yield, whereby r2 = 0.77, p 0.3 may be used as a cut-off value for the initiation of PB CD34+ quantifi cation prior to stem cell harvest.

The clinical significance of immature reticulocyte fraction during radiotherapy and chemotherapy in patients with tumor / 国际检验医学杂志

Objective To investigate the changes of peripheral blood parameters before and after radiotherapy and chemothera-py ,and establish an early index that can reflect the suppression and recovery of the bone marrow hematopoietic function in patients with tumor .Methods The white blood cell(WBC) ,neutrophils(NEU) ,the percentage of reticulocyte(Ret% ) and the immature re-ticulocyte fraction(IRF) of peripheral blood were detected by Sysmex XT-2000i automatic blood cell analyzer before and after radio-therapy and chemotherapy in 50 patients with tumor .Results Bone marrow function was suppressed after radiotherapy and chemo-therapy .Compared with the value before radiotherapy and chemotherapy ,IRF and Ret% were significantly decreased on the 3rd day after therapy which was 3 days earlier than the change of WBC and NEU ,the difference was statistically significant (P<0 .05) ,and compared with the value of the 10th day ,IRF began to rebound on the 15th day which was 5 days earlier than the change of Ret%and NEU ,the difference was statistically significant (P<0 .05) .Conclusion IRF can be served as an early and sensitive indicator in monitoring the suppression and recovery of bone marrow hematopoietic function in the patients with tumor during radiotherapy and chemotherapy .

Clinical significance of immature reticulocyte fraction in patients with acute myeloid leukemia following consolidation chemotherapy with high-dose cytarabine / 白血病·淋巴瘤

Objective To investigate the clinical significance of peripheral blood parameters including immature reticulocyte fraction (IRF) in monitoring the hematopoietic recovery of patients with acute myeloid leukemia aftcr receiving consolidation chemotherapy with high dose cytarabine (HDAC).Methods The peripheral blood parameters,including absolute neutrophil (ANC) and platelet (Plt) counts as well as IRF,were measured by Sysmex XE-2100 automated hematology analyzer before and after consolidation chemotherapy with HDAC in 30 patients with acute myeloid leukemia.These peripheral blood parameters were further statistically analyzed and compared.Results Following consolidation chemotherapy,the median time to recovery for ANC,Plt and IRF was (9.2±2.5) days,(11.3±3.7) days and (5.0±2.6) days,respectively.In comparison with ANC and Plt recovery,IRF showed significantly early recovery (P ＜ 0.05).Additionally,ANC raised preceding Plt recovery (P ＜ 0.05).However,the median recovery time of ANC,Plt and IRF showed little difference among these patients further subgrouped according to FAB and risk based classification (P ＞ 0.05).Conclusion IRF is an early indicator for the hematopoietic recovery of patients with acute myeloid leukemia following consolidation chemotherapy with HDAC,which could provide important clinical information to evaluate therapeutic efficacy.

Evaluación de la fracción de reticulocitos inmaduros como parámetro de ferropenia en el embarazo / Evaluation of the fraction of immature reticulocytes as a parameter of iron deficiency in pregnancy

Las embarazadas constituyen un grupo susceptible de desarrollar anemia ferropénica, la cual produce una alteración de la hematopoyesis, con aumento de reticulocitos principalmente a expensas de la fracción de reticulocitos inmaduros (IRF). El objetivo de este trabajo ha sido evaluar la sensibilidad (S) y especificidad (E) del IRF para el diagnóstico temprano de la deficiencia de hierro en el embarazo. Se obtuvieron muestras de sangre de 99 embarazadas que concurrieron al laboratorio del Hospital Vélez Sarsfield para su control prenatal. Se realizó el hemograma y el recuento reticulocitario en un autoanalizador hematológico, y se determinaron el hierro sérico y la ferritina. Se halló una sensibilidad de 76,1% y una especificidad de 53,1% por medio del análisis de la curva ROC (receiver- operating characteristic curve) para un valor de IRF de 0,35. La comparación de parámetros hematológicos y bioquímicos de las muestras con IRF menor o mayor a 0,35 muestran diferencias significativas (p<0,05). Por estos datos se podría recomendar esta prueba para el diagnóstico precoz de la deficiencia de hierro.

Pregnant women constitute a group capable of developing iron deficiency anemia, which causes a disturbance of hematopoiesis, with increased reticulocyte mainly at the expense of the immature reticulocyte fraction (IRF). The aim of this work was to assess IRF sensitivity (S) and specificity (E for its name in Spanish) for early diagnosis of iron deficiency in pregnancy. Blood samples from 99 pregnant women who attended Vélez Sarsfield Hospital Laboratory for prenatal care. Complete blood cells and reticulocyte automated counts were performed and serum iron and ferritin were analyzed. A 0.35 IRF cutoff was taken when the ROC curve (receiver-operating characteristic curve) was evaluated and a 76.1% sensitivity and 53.1%. specificity were found. Comparison of hematological and biochemical parameters of the samples with IRF lower and higher than 0.35 shows significant differences (p<0.05). These results make it possible to recommend this test for early diagnosis of iron deficiency.

Subpopulações dos reticulócitos e fração de reticulócitos imaturos como indicadores de aumento da eritropoese em doentes com anemia por deficiência de ferro / Reticulocyte subpopulations and immature reticulocyte fractions as indicators of increased erythropoiesi in patients with iron deficiency anaemia

O objetivo deste trabalho é o de estudar as subpopulações dos reticulócitos e a fração de reticulócitos imaturos (IFR) enquanto indicadores de atividade eritropoética em pacientes com anemia por deficiência de ferro e determinar o seu grau de correlação com os marcadores tradicionais de deficiência de ferro. Estudamos um total de 96 indivíduos, com idades compreendidas entre os 20 e os 86 anos, divididos em dois grupos: indivíduos controle (n=30) e indivíduos com anemia por deficiência de ferro (n=66). A todos eles foi efetuado hemograma completo, incluindo contagem de reticulócitos e os seus índices de maturação, ferro, transferrina, ferritina e capacidade total de fixação do ferro. Os indivíduos com anemia por deficiência de ferro mostraram um aumento da proporção de IFR quando comparados com o grupo controle (15.02 ± 9.70 por cento vs 6.43 ± 3.98 por cento, p<0.01, respectivamente). Em relação às subpopulações dos reticulócitos, no grupo de pacientes encontramos um aumento na proporção de reticulócitos com valores médios de fluorescência (12.69 ± 6.69 por cento vs 5.88 ± 3.59 por cento, p<0.01) e na proporção de reticulócitos com alta fluorescência (1.45 [0.38-3.10] vs 0.40 [0.00-0.90], p<0.05) e diminuição na proporção de reticulócitos com baixa fluorescência (84.83 ± 9.65 por cento vs 93.57 ± 3.98 por cento, p<0.01). Foi encontrada correlação, positiva ou negativa, entre os parâmetros de maturação dos reticulócitos entre si, e destes com o RDW (red cell distribution width). Não foi encontrada correlação com os outros indicadores laboratoriais de deficiência de ferro. Em conclusão, a anemia por deficiência de ferro está associada com aumento da proporção de IFR, refletindo aumento da atividade eritropoética destes pacientes.

The aim of this work is to investigate reticulocyte subpopulations and immature reticulocyte fractions as indicators of bone marrow erythropoietic activity in patients with iron-deficiency anemia and their correlations with traditional hematological and biochemical markers of iron deficiency. A total of 96 individuals, aged 20 to 86 years old, were included in this study. These individuals were divided into two groups: healthy controls (n=30) and iron-deficiency anemia (n=66). Complete blood counts including reticulocytes and their subpopulations, iron, ferritin and transferrin and total binding capacity were determined in all individuals. Patients with iron-deficiency anemia had an increased proportion of immature reticulocyte fractions when compared with controls (15.02 ± 9.70 percent vs. 6.43 ± 3.98 percent, p<0.01, respectively). Comparing patients with healthy controls, the investigation of the subpopulations revealed higher medium-fluorescent reticulocyte (12.69 ± 6.69 percent vs. 5.88 ± 3.59 percent, respectively p<0.01) and high-fluorescent reticulocyte (1.45 [0.38-3.10] vs. 0.40 [0.00-0.90], p<0.05) regions and a smaller low-fluorescent reticulocyte region (84.83 ± 9.65 percent vs. 93.57 ±3.98 percent, p<0.01). Positive or negative correlations were found between reticulocyte subpopulations and red cell distribution width. No correlation was found with the other iron deficiency markers. In conclusion, iron deficiency anemia is associated with an increased proportion of immature reticulocyte fractions, reflecting an increase in erythropoietic activity in these patientss.

Clinical Significance of Reticulocyte Maturation Parameters in the Differential Diagnosis of Macrocytic Anemias / 대한진단검사의학회지

BACKGROUND: Macrocytic anemias are commonly seen in clinical practice, and precise etiologic diagnosis is essential for proper management. We evaluated the clinical utility of reticulocyte maturation parameters in macrocytic anemias to discriminate among myelodysplastic syndrome (MDS), megaloblastic anemia (MA), and non-megaloblastic macrocytic anemia associated with chronic liver disease (MA-CLD). METHODS: Using an automated reticulocyte counter, we retrospectively analyzed and compared reticulocyte maturation parameters including immature reticulocyte fraction (IRF), mean reticulocyte volume (MRV), mean sphered cell volume (MSCV) of normal control (N=34), and patients diagnosed with MDS (N=31), MA (N=52), and MA-CLD (N=196). RESULTS: Macrocytic anemias from MA, MDS and MA-CLD showed higher values of reticulocyte maturation parameters including IRF, MRV and MSCV than normal control (P or = 0.39), MRV (> or = 129.5 fL), and MSCV (> or = 102.3 fL) makes the diagnosis of MA-CLD unlikely and underlying MDS should be considered.

Clinical Significance of Immature Reticulocyte Fraction and Reticulocyte Cellular Indices in Pediatric Anemia Patients / 소아과

PURPOSE: Flow cytometric automated reticulocyte analysis is a superior method to manual reticulocyte counting, with respect to precision and sensitivity. Furthermore, flow cytometric analysis is able to measure immature reticulocyte fraction(IRF) and reticulocyte cellular indices(RCI:cell hemoglobin content: CHr, mean cell volume:MCVr, cell hemoglobin concentration mean:CHCMr, distribytion width:RDWr, HDWr, CHDWr). In this study, we investigated the mean values and clinical significances of IRF and RCI in healthy children and pediatric anemia patients. METHODS: IRF and RCI were measured with an automated blood cell analyzer, ADVIA 120(Bayer, USA) using oxazine 750 dye, in 57 healthy children and 61 children with anemia. The anemia group consisted of 27 iron deficiency anemia(IDA) patients and 34 patients with anemia associated with acute infection(AAI). We compared the mean values of IRF and RCI in the control group classified according to age, between anemia groups and the control group, and between the IDA group and the AAI group. RESULTS: For the normal control group, the mean values of IRF, CHr, MCVr and HDWr were higher in neonates when compared to older children. The mean values of IRF and RDWr were significantly higher, and the mean values of CHr and CHCMr were significantly lower in the IDA group when compared to the control group. The mean value of IRF was significantly higher, and the mean value of CHDWr was significantly lower in the AAI group when compared to the control group. The mean values of IRF, CHr and CHCMr were significantly lower in the IDA group when compared to the AAI group. CONCLUSION: We could determine the normal mean values of IRF and RCI in healthy children classified according to age for understanding of hematopoietic response differences according to age. The evaluation of IRF and RCI by automated reticulocyte analyzer seemed to be accurate and clinically useful for the early diagnosis of anemia and the differentiation of IDA from AAI.

Immature Reticulocyte Fraction after Iron Therapy for Iron Deficiency Anemia / 대한혈액학회지

BACKGROUND: Automated counting of reticulocyte introduced new reticulocyte parameters such as immature reticulocyte fraction (IRF). IRF is thought to be more sensitive than absolute or corrected reticulocyte count for detecting recovery of bone marrow function. The aim of this study is to assess the role of IRF for predicting the response of therapy after treatment of iron deficiency anemia. METHODS: Patients with previously untreated iron deficiency anemia (blood hemoglobin 0.15) and 10 of them (91%) had their hemoglobin level increased by more than 3g/dL. This difference was significant (P=0.024). However, the 8th day IRF was not correlated with the change of hemoglobin as strongly as the 8th day corrected reticulocyte count (Pearson coefficient 0.420 vs 0.693). CONCLUSION: For the patients with iron deficiency anemia, the 8th day of treatment IRF correlates with the response of iron treatment, but the 8th day of treatment corrected reticulocyte count has a stronger correlation.

Evaluation of NeonatalImmature Reticulocyte Fraction in Small-for-gestational Age Infant in Umbilical Cord Blood / 대한산부인과학회잡지

OBJECTIVE: To evaluate the immature reticulocyte fraction (IRF) by automated calculator that have played a role of predicting marker for hematopoiesis induced by perinatal asphyxia. METHODS: Hospital charts of 40 neonates with diagnosis of small for gestational age (SGA: birth weight <10 percentile) and 47 babies of appropriate for gestational age (AGA) who were delivered vaginally between May 8, 2000 and March 2, 2002 at department of Obstetric and Gynecology, Sanggye Paik Hospital, Inje university. About 5 cc in cord blood was collected immediately after delivery, the calculation of nucleated RBC (N-RBC)/100WBC by macroscopic exam and the evaluation of reticulocyte maturation by automated reticulocyte calculator (Sysmex SE 9000, TOA Medical Electronics Co., Ltd, Kobe, Japan) were performed, and made a comparative study of apgar score. RESULTS: The comparison between AGA and SGA infants, the mean values of cord blood sampling parameter N-RBC (3.53 +/- 4.89 vs 7.92 +/- 10.06, P=0.016), middle fluorescence ratio reticulocyte (MFR) (0.21 +/- 0.02 vs 0.23 +/- 0.03, P<0.001), high fluorescence ratio reticulocyte (HFR) (0.08 +/- 0.03 vs 0.12 +/- 0.03, P<0.001), IRF (0.28 +/- 0.03 vs 0.35 +/- 0.05, P<0.001) were obtained. All of the parameters were significantly different between SGA infants and normal infants and IRF was more valuable marker than N-RBC in evaluation of hematopoietic activity in SGA infants (multiple logistic regression analysis: P value 0.282 vs <0.001). CONCLUSION: Immature reticulocyte fraction by automated calculator is more accurate and confident marker better than N-RBC/100WBC by manual countingin evaluation of the fetal hypoxic induced hematopoiesis.

Clinical Utility of Reticulocyte Parameters in the Early Detection of Hematopoietic Engraftment After Stem Cell Transplantation / 대한진단검사의학회지

BACKGROUND: Allogeneic or autologous bone marrow transplantation (BMT) or peripheral blood stem cell transplantation (PBSCT) has been settled a modality of treatment in hematologic malignantdisorders or solid tumors. Because engraftment or not was important for the direction of treatment and prognosis of the patients, various methods, judging it early were groped. Instead of an absoluteneutrophil count (ANC) or platelet count in PB, we used reticulocyte parameters as early predictors of hematopoietic engraftment. METHODS: We measured the ANC with reticulocyte parameters daily in 25 patients receiving allogeneic BMT or PBSCT (n=17, 30.82+/-9.97 years old) and autologous PBSCT (n=8, 30.63+/-8.55 years old) from January 2002 to February 2003 in Kyungpook National University Hospital. Wedefined erythroid engraftment as the first day of a mean corpuscular volume of reticulocyte (MCVr)>or=105 fL and immature reticulocyte fraction (IRF) >or=10% in the second rising peak and myeloid engraftment as the first day of ANC >or=500/microL. RESULTS: The erythroid engraftment occurred after a mean time of 16.24+/-4.16 days in allogeneic graft and 14.00+/-3.55 days in autologous graft and the myeloid engraftment occurred 17.94+/-3.23 days and 15.00+/-2.78 days, respectively. In the allogeneic graft, the erythroid engraftment occurred earlier than the myeloid engraftment (P=0.03). In the autologous graft, the erythroid engraftment preceded the myeloid engraftment; however, it was not statistically significant (P=0.47). Among 3 cases, wherein the erythroid engraftment occurred later than the myeloid engraftment in allogeneic graft, 2cases were ABO-incompatible PBSCT. CONCLUSIONS: Considering that the successive increase of immature reticulocytes preceded that of ANC in most cases, we concluded that as an early indicator of hematopoietic engraftment, reticulocyte parameters such as IRF and MCVr were useful especially observing them simultaneously.

Clinical Significance of Immature Reticulocyte Fraction Determined by Automated Blood Cell Analyzer / 대한혈액학회지

BACKGROUND: Compared with traditional manual method, automated counting of reticulocytes offers greater sensitivity, improved accuracy, and less subjectivity. Also, automated blood cell analyzer enabled to measure immature reticulocyte fraction (IRF). In this study, we investigate the clinical significance of IRF in the evaluation of anemia. METHODS: Reticulocyte counts were measured with automated blood cell analyzer, Technicon H*3 (Bayer Diagnostics, USA) and manual method from 100 cases of anemic group and 20 cases of control group. Then, we compared the values of reticulocyte count between manual method and H*3. For investigate clinical significance of IRF in the evaluation of anemia, IRF determined by H*3 was compared with the absolute reticulocyte count (ARC) and with the reticulocyte production index (RPI). In addition, we subclassified anemic group into 5 different subgroups, such as hemolytic anemia or anemia due to hemorrhage, hematologic malignancy, anemia due to chronic renal failure, iron deficiency anemia, and anemia of chronic disorders. The value of ARC and IRF in each group was analysed. RESULTS: 1) The mean reticulocyte count by H*3 was higher than that by the manual method and the result of these two methods was correlated well (r=0.98, P0.05) with RPI. 3) Both ARC and IRF were increased in patients with hemolytic anemia or anemia due to hemorrhage. High mean value of IRF with reduced ARC were shown in hematologic malignancy. IRF were within normal range with reduced ARC in the group of chronic renal failure. Both IRF and ARC were within normal range in the group of iron deficiency anemia. In anemic group due to chronic disorder, ARC were within normal range with increased IRF. CONCLUSION: reticulocyte counting by the automated blood cell analyzer H*3 allows the improvement of accuracy and sensitivity. Immature reticulocyte fraction can be used for differentiation of various anemic disorders together with absolute reticulocyte count.