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PubMed1996

Assessing erythropoiesis and the effect of erythropoietin therapy in renal disease by reticulocyte counting.

Renal disease is characterized by failure of erythropoietin (Epo) production and low bone marrow sensitivity to Epo. The reticulocyte count is the best laboratory marker of erythropoiesis available, but reticulocytes have not been extensively studied in renal disease. Cluster analysis suggests that in non-haemodialysed renal patients the anaemia is associated with uraemia while the reticulocyte number and immature subclasses are correlated with the ineffective erythropoietic component of the anaemia. This emphasizes the importance of treating the renal disease in patients with the anaemia of end-stage renal failure. Human recombinant Epo therapy has been demonstrated to be effective in correcting anaemia in most cases of chronic renal insufficiency. In renal patients the reticulocyte count should only be monitored by automated methods to assure reliability at low counts.

Anemia↗
PubMed1976

Spinner films for reticulocyte counts.

The widely practiced method for performing a reticulocyte count includes counting 1000 normal erythrocytes while searching for a relatively small population of reticulocytes. A method is presented using a spinner reticulocyte preparation which avoids the need to count the normal erythrocytes, thereby eliminating most of the tedium from the test. The accuracy and reproducibility of this new method, as compared to the currently practiced method, is presented, along with the results of an on-line comparison.

Erythrocyte Count↗
PubMed1999

Highly fluorescent reticulocyte count predicts haemopoietic recovery after immunosuppression for severe aplastic anaemia.

Highly fluorescent reticulocyte (HFR) counts are the most reliable and sensitive index of haemopoietic recovery after bone marrow or peripheral blood stem cell transplantation. We report the behaviour of HFRs during haemopoietic recovery in two patients who were affected by severe aplastic anaemia (SAA) and treated with horse antithymocyte globulin (ATG), cyclosporin A (CsA) and granulocyte colony-stimulating factor (G-CSF). A HFR value > 5% of the total reticulocyte count, a reticulocyte count > 30 x 10(9)/l, and a polymorphonuclear (PMN) count > 0.5 x 10(9)/l were found after 9 and 8, 20 and 46, and 16 and 22 days, respectively, after the end of ATG. HFR recovery to > 5% anticipated the rise of PMN > 0.5 x 10(9)/l by at least 7 and 14 days, respectively. Thus, HFR evaluation could be used as a reliable and early marker of response to immunosuppression in severe aplastic anaemia.

Adolescent↗
PubMedDate not supplied

Analysis of reticulocyte counts using various methods.

The precision and accuracy of manual reticulocyte counts using the Miller disc reticle, other ruled reticle and no reticle are compared with the reticulocyte results from the automated Hematrak 590 instrument. Two slides of each of 50 patient blood specimens were sent to the hematology laboratories of each of six participating hospitals. In addition to between-method comparison (precision), the manual method results using the three different counting techniques were each compared with the Hematrak results to determine if there were significant differences in reported results (accuracy). Statistical analysis revealed that the Miller disc method was the most precise and accurate manual method as compared with the Hematrak. Methods without a Miller disc reported significantly higher reticulocyte counts. Imprecision was also higher among non-Miller manual methods. By using the Miller disc, the accuracy and precision of manual methods may be increased to that of the automated Hematrak method.

Anemia↗
PubMed1987

Flow cytometric reticulocyte counting with thioflavin T in a clinical hematology laboratory.

Flow cytometric measurement of reticulocyte counts, using the cationic dye thioflavin T, was implemented in a clinical hematology laboratory. Results obtained correlated well with manual reticulocyte counts using new methylene blue, but the reproducibility of counts done with the flow cytometer was much greater than that with manual counts. The new procedure permitted a reduction in laboratory staff, but required an intensive period of training for technologists. Utilization of the cytometer required about four hours per day of machine time for 60 counts, permitting implementation of other flow cytometric assays in the clinical laboratory.

Benzothiazoles↗
PubMed1995

Blood reticulocyte count and plasma lactate dehydrogenase activity are positively related to the free fatty acid/albumin ratio in geriatric patients.

The objective of this study was to investigate the in vivo relationship between plasma free fatty acid (FFA)/albumin molar ratio and indicators of cellular damage. A case series study was carried out in 20 geriatric patients in a stable clinical condition. Their plasma albumin concentration was in the range 26-42 g l-1. There was a significant positive correlation between the FFA/albumin ratio and (a) reticulocyte count (r = 0.61, p = 0.006), (b) lactate dehydrogenase activity (r = 0.69, p = 0.002), and (c) haptoglobin concentration (r = 0.46, p = 0.05). The haemoglobin concentration was inversely related to relative reticulocyte count (r = -0.55, p = 0.01). Absolute and relative reticulocyte counts were positively associated (r = 0.92, p < 0.0001). The results are in accordance with the contention that a high FFA/albumin ratio in vivo may elicit cellular damage. Further studies are required to elucidate to what extent a high FFA/albumin ratio might be causally related to diseases.

Aged↗
PubMed1996

Changes in serum erythropoietin and the reticulocyte count during chemotherapy for leukemias.

We serially determined serum erythropoietin (Epo) and the reticulocyte count in patients with various types of leukemia during chemotherapy. Serum Epo increased soon after the initiation of chemotherapy and decreased after the termination of therapy irrespective of the types of leukemia or treatment regimen. However, it did not stay at low level but fluctuated. The reticulocyte count, on the other hand, showed a transient rise while serum Epo level descended. The value of serum Epo when increased was higher than the value expected from hemoglobin concentration; this finding was similar to that in aplastic anemia. These results suggest that myelosuppression is a major factor for the increase in serum Epo level during leukemia chemotherapy.

Adult↗
PubMedDate not supplied

[Evaluation of reticulocyte count on Cell-Dyn 3500 automate: comparison with a flow cytometry technique].

Cell-Dyn 3500 automate (Abbott) provides reticulocyte count using a recent software, after ribosomal RNA colouring with methylene blue reagent. The aim of this study was to evaluate results from Cell-Dyn 3500, and to compare them with the routine laboratory technique by flow cytometry (FacScan, Becton-Dickinson). Cell-Dyn 3500 analytical parameters (inter- and intra-assay precision, sample-to-sample contamination) were good and in accord to manufacturer's specifications. Reticulocyte values from blood samples kept at 4 degrees C during 3 days were unchanged. Usual values in 145 normal patients were found between 71.3 and 78.3 G/l with Cell-Dyn 3500, between 119.3 and 130.2 G/l with FacScan. Both techniques were compared in 87 patients with various anemias: Cell-Dyn 3500 showed more frequently high reticulocyte values in regenerative anemias (hemorrhagic), but was less performant for classification of aregenerative anemias. Reticulocyte count with Cell-Dyn 3500 is a semi automatic, easy to perform and swift technique, using no toxic reagent but unitary test tubes kept at room temperature. The test cost is however high, and Cell-Dyn 3500 cannot be used during the analysis.

Flow Cytometry↗
PubMed1995

Serum erythropoietin and reticulocyte counts in inflammatory process.

The role of erythropoietin in the pathogenesis of anaemia associated with inflammatory disorders is unclear. We studied serum erythropoietin levels in patients with inflammatory process of varying aetiologies. Serum erythropoietin levels and reticulocyte counts were prospectively measured in 40 patients with inflammatory syndromes and compared with values obtained in 20 patients with myelodysplastic syndromes. Significant inverse correlation between erythropoietin levels and haemoglobin concentration were noted in the 2 groups. The slope of the regression line for patients with inflammatory disorders was lower as compared with that for the myelodysplastic syndromes. In all cases, when the erythropoietin response in relation to degree of anaemia is compared with that which occurs in patients with myelodysplastic syndromes, the inadequate erythropoietin response in patients with chronic inflammatory process becomes evident. In patients with inflammatory process, a relationship between erythropoietin levels and reticulocyte counts were only noted in patients with mildly anaemia (haemoglobin concentration higher than 10.5 g/dl). This study suggests blunted erythropoietin production and impaired marrow response to this hormone in the anaemia which occurs in inflammatory syndromes and supports the hypothesis that these disorders may contribute to the development of the anaemia associated with inflammatory disorders.

Adult↗
PubMed1990

Reticulocyte count using thiazole orange. A flow cytometry method.

Recently flow cytometry techniques have been developed to replace the microscope reticulocyte count. We used thiazole orange, a RNA binding fluorochrome, to discriminate reticulocytes from mature erythrocytes. Thiazole orange and the Retic-COUNT software package were evaluated for performance of routine analysis on different flow instruments. The applied methodology analysed 10(4) cells semi-automatically in an easily performed manner. Consistent results were obtained with dipotassium EDTA anticoagulated blood (stable for 30 h after venesection), with incubation times in thiazole orange solution ranging from 2 to 7 h at 25 degrees C. This allowed flexibility in specimen collection and storage and assay performance with no change in results. Changes of incubation temperature up to 30 degrees C had no measurable effect. The values obtained showed good linearity, precision and accuracy for normal, low and high reticulocyte counts. However interferences were observed: RBC autofluorescence, nucleated RBC, Howell-Jolly bodies, high leucocyte count, high platelet count and giant platelets, all falsely increased the number of reticulocytes. These artifacts were eliminated by software gate corrections, thus leaving less than 5% of the specimen to be reanalysed by the microscopic method. The thiazole orange flow cytometric method was determined to be a fast, reliable method for the routine clinical quantitation of reticulocytes.

Benzothiazoles↗
PubMed2001

Ratio of baseline erythropoietin (EPO) level and corrected reticulocyte count as an indicator for a favourable response to recombinant human erythropoietin (rhEPO) therapy in anaemic cancer patients.

PURPOSE: Recently, recombinant human erythropoietin (rhEPO) was introduced for the management of anemia in malignancy. To identify an indicator for a favourable response to rhEPO, 28 anaemic cancer patients undergoing chemotherapy and treated with rhEPO were evaluated. METHODS: Patients were classified into responder (16 of 28, 57%) and nonresponder (12 of 28, 43%) groups according to their responses to rhEPO therapy (response being defined as an increase in Hb level of > 2 g/dl from baseline without blood transfusion). RESULTS: Treatment with rhEPO showed significant improvements in the red blood cell (RBC) count, haemoglobin (Hb), packed cell volume (PCV), and reticulocyte count (ret. count) after 4 weeks. Upon analysing the baseline value of the EPO level and the corrected ret.count in these two groups, we found that the ratio of the EPO level and the corrected ret.count (EPO/ret.count) demonstrated a statistical significance (P = 0.03) in the prediction of response to rhEPO therapy. This ratio showed a sensitivity of 87.5%, specificity of 66.7%, and overall accuracy of 78.6%. CONCLUSION: Our study suggested that the baseline ratio of EPO/ret.count should be used as an indicator for a favourable response to rhEPO therapy.

Adult↗
PubMed1994

Reticulocyte counts in canine and rat blood made by flow cytometry.

Absolute and percentage reticulocyte counts for sequestrated blood samples from healthy Wistar rats (n = 132) and beagles (n = 64) were made by thiazole orange and flow cytometry. The flow cytometric method showed good agreement with a manual counting method for both species, and the precision data for both of these counting methods were similar.

Animals↗
PubMed1998

Decreasing reticulocyte counts associated with declining post-dose erythropoietin plasma levels in anaemia of prematurity.

UNLABELLED: A prospective sequential, multicentre trial was conducted to determine the association between erythropoietin (EPO) plasma levels and the erythropoietic response to recombinant human erythropoietin (r-HuEPO) during long-term treatment of premature infants. Twenty-nine infants, gestational ages 26-34 weeks and postnatal ages more than 14 days, received 600 IU r-HuEPO per kg per week divided into three doses subcutaneously for haemoglobin levels less than 120 g/l or haematocrit less than 36% over a period of 4 weeks. Eight additional patients were studied for a total of 10 weeks. EPO plasma concentrations and haematologic parameters were measured prior to the onset of treatment and at 2-weekly intervals thereafter. Treatment with r-HuEPO resulted in a median increase in corrected reticulocyte counts of 2.5% (range 0.2-4.6%) above patient's baseline, thereafter a decrease was observed. In the 8 patients followed for 10 weeks reticulocyte counts declined significantly during weeks 6-10 when compared with the first 4 weeks (p < 0.005). Median 72-hour post-dose EPO plasma levels increased significantly (p < 0.0001) to 57.3 mU/ml (range 5.0-160) above patient's baseline after the first injection, but declined progressively thereafter until they approached baseline values at week 10. CONCLUSION: R-HuEPO treatment after the first month was associated with a decrease in post-injection plasma levels and a decrease in erythropoietic response. This decrease in erythropoietin's efficacy and the decline observed in post-dose EPO plasma levels may be causally related.

Anemia↗
PubMed2004

Comparison of cost effectiveness between measuring the serum erythropoietin level and reticulocyte count for monitoring thalassemic patients: a note in Thai beta thalassemia/Hb E subjects.

Iron deficiency anaemia and the thalassemia syndromes, a group of disorders resulting from inherited abnormality of globin chain production, are common causes of anaemia in Thailand, and in the Far East in general. Monitoring erythropoiesis in these patient is very important in evaluating the disease and the response to treatment. Recently, our group has just reported the feasibility in using serum erythropoietin (EPO) for monitoring purposes in thalassemia and demonstrated that the determination of serum EPO can be an alternative choice in the follow up of these conditions. This study reports a cost effectiveness analysis comparing the recently reported radioimmunoassay (RIA) for serum EPO determination and the previously used tool, the reticulocyte count. The study reports a higher detection rate for ineffective erythropoiesis when using serum EPO determination, however, the increased sensitivity is at balanced by a higher unit cost. In this analysis, the cost effectiveness for serum EPO and reticulocyte are 208.33 and 50 baht/detection, respectively. () Therefore, the reticulocyte count is more cost effective and is recommended for routine usage in our current medico-economic setting.

Anemia, Iron-Deficiency↗