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Reticulocyte Fraction (reticulocyte + fraction)
Kinds of Reticulocyte Fraction Selected AbstractsThe utility of immature reticulocyte fraction as an indicator of erythropoietic response to altitude training in elite cyclistsINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1p2 2010V. S. NADARAJAN Summary Altitude training is sometimes employed by elite endurance athletes to improve their sea level performance. This improvement results from the increased red cell mass consequent upon the boost in erythropoietin (EPO) level that occurs as a response to the relatively hypoxic environment at high altitudes. We measured serum EPO levels together with various red cell and reticulocyte parameters including immature reticulocyte fraction (IRF) in eight national track-endurance cyclists, resident at sea-level, prior to and upon return from an altitude of approximately 1905 m. Reticulocytes and soluble transferrin receptor (sTfR) were significantly increased with reduction in ferritin levels immediately on return from high altitude indicating increased erythropoietic activity. IRF in particular showed a significant peak immediately on return but decline to sub-baseline levels by day 9, and recovery to baseline by day 16. Our results indicate that IRF is a sensitive marker of erythropoietic status in athletes undergoing altitude training and subsequent loss of EPO stimuli on return to sea level. [source] Quality counts: new parameters in blood cell countingINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2009C. BRIGGS Summary Recently several parameters have been introduced to the complete blood count such as nucleated red blood cells, immature granulocytes; immature reticulocyte fraction, immature platelet fraction and red cell fragments as well as new parameters for detection of functional iron deficiency. Leucocyte positional parameters, which may diagnose specific diseases (e.g. differentiate between abnormal lymphocytes in leukaemia and viral conditions and may also detect malarial infection) are now available. At this time they are only used for research; however, generally such parameters later become reportable. One manufacturer's routine analyser allows measurement of cells by flow cytometry using monoclonal antibodies. Currently, there are no accredited external quality assessment schemes (EQAS) for these parameters. For a number of parameters, on some instruments, there is no internal quality control, which brings into question whether these parameters should be used for clinical decision making. Other more established parameters, such as mean platelet volume, red cell distribution width and the erythrocyte sedimentation rate do not have EQAS available. The UK National EQAS for General Haematology held a workshop earlier this year in 2008 to discuss these parameters. Participants were asked to provide a consensus opinion on which parameters are the most important for inclusion in future haematology EQAS. [source] Utility of reticulocyte maturation parameters in the differential diagnosis of macrocytic anemiasINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 5 2003A. Torres Gomez Summary The aim of this study was to test the clinical utility of reticulocyte maturation parameters in the differential diagnosis of macrocytic anemias. Using an automated reticulocyte counter, we analyzed immature reticulocyte fraction (IRF), mean reticulocyte volume (MRV) and mean fluorescence index (MFI) in peripheral blood samples from healthy donors (n = 30), patients diagnosed with myelodysplastic syndromes (MDS, n = 35), with megaloblastic anemia (MA, n = 10) and with non-megaloblastic macrocytic anemias (NMMA, n = 30). Macrocytic anemias due to ineffective erythropoiesis (MA and MDS) showed reticulocytes skewed to a more immature fraction. Therefore, they have a larger volume and a greater RNA content than healthy controls. Interestingly, reticulocytes in both low and high risk MDS are significantly larger (127.3 vs. 118.3 fl, P < 0.01) and have a greater RNA content (MFI 20.5 vs. 12.9, P < 0.01 and IRF 22.5 vs. 9.1%, P < 0.01) than NMMA patients. We conclude that measurement of reticulocyte maturation parameters may be a very useful tool in the differential diagnosis of macrocytic anemia. The presence of extremely high values of IRF (>16%), MFI (>18) and MRV (>129 fl), makes the diagnosis of NMMA very unlikely. An underlying MDS should, therefore, be sought. [source] Patterns of pseudo-reticulocytosis in malaria: fluorescent analysis with the Cell-Dyn® CD4000INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2002C. S. SCOTT This study of Plasmodium falciparum malaria evaluated patterns of fluorescent reticulocyte measurements as determined with the Abbott Cell-Dyn® CD4000. The parasitaemia of positive samples (n=180) ranged from 0.04% to 25.5%, with those (19/180) showing gametocytes having lower parasitaemia levels (mean 0.31%, median 0.2%) compared to those that did not (mean 2.59%, median 0.8%). There was a reasonable association (R2=0.60) between parasitaemia level and CD4000 reticulocyte percentages, although there was overall a small statistical bias towards higher parasitaemia estimates determined microscopically. Consistently high immature reticulocyte fraction (IRF) values of >0.5 were observed in cases with a parasitaemia exceeding 5%, while samples with lower parasitaemia levels showed more variable IRF values. Visual examination of CD4000 reticulocyte histograms revealed that 81/100 malaria-positive samples with an IRF above 0.5 showed the presence of a fluorescent population `spike' consistent with the staining of intracellular malaria parasites. Only three of the 80 malaria-positive samples with an IRF below 0.5, and none of the 237 malaria-negative samples, showed this histogram pattern. These observations indicate that samples with malaria parasites give erroneously high CD4000 reticulocyte estimates that essentially comprise the sum total of true reticulocytes and parasite-infected red cells (pseudo-reticulocytes). This limitation is common to all automated reticulocyte procedures but recognizing the differences between homogenous staining parasitized red cells and heterogeneous staining reticulocytes has potential applications in monitoring parasitaemia levels both at patient presentation and during subsequent treatment. [source] Hematopoietic progenitor cells (HPC) and immature reticulocytes evaluations in mobilization process: new parameters measured by conventional blood cell counterJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2006J.F.A. Noronha Abstract Monitoring the timing of leukapheresis in peripheral blood stem cells (PBSC) mobilization is an important clinical decision that requires an accurate analytical tool. The present study assessed hematopoietic progenitor cells (HPC) and immature reticulocyte fraction (IRF) counts provided by a routine automated blood counter as potential parameters for predicting the appropriate time for harvesting. The HPC and IRF values were compared with white blood cell (WBC) and CD34+ cell counts obtained by flow cytometry in 30 adult patients with hematological malignancies undergoing PBSC mobilization. It was observed that there was a significant correlation between HPC counts and CD34+ cells in peripheral blood counts (r=0.61, P=0.0003) and between the number of HPC and CD34+cells collected by leukapheresis (r=0.5733, P=0.0009). Comparing HPC, IRF, WBC, and CD34+ cells parameters as a sign of hematological recovery showed that the raise in immature reticulocytes counts preceded the increase of WBC (P=0.0002), HPC (P=0.0001), and CD34+ (P=0.0001) cells in peripheral blood counts. According to our results, HPC and IRF parameters may be integrated into clinical protocols to evaluate the timing of leukapheresis. IRF, as previously demonstrated in bone marrow transplantation, is the earliest sign of hematopoietic recovery in mobilization process. J. Clin. Lab. Anal. 20:149,153, 2006. © 2006 Wiley-Liss, Inc. [source] | ||||||||||