Utility of reticulocyte maturation parameters in the differential diagnosis of macrocytic anemias

Diagnostic performance of automated red cell parameters in predicting bone marrow iron stores

OBJECTIVES

The aim of the study was to determine the diagnostic performance of novel automated red cell parameters for estimating bone marrow iron stores.

METHODS

The study was a retrospective single-centre study based on data from an automated haematology analyser and results of bone marrow iron staining. Red cell parameters were measured on a Sysmex XN-series haematology analyser. Bone marrow iron stores were assessed semiquantitatively by cytochemical reaction according to Perls.

RESULTS

The analysis included 429 bone marrow aspirate smears from 393 patients. Median age of patients was 67 years, 52 % of them were female. The most common indication for bone marrow examination was a plasma cell dyscrasia (n=104; 24 %). Median values of percentage of hypochromic and hyperchromic red blood cells (%HYPO-He, %HYPER-He), reticulocyte haemoglobin equivalent (RET-He) and microcytic red blood cells (MicroR) were statistically significantly different between cases with iron deplete and iron replete bone marrow. In a logistic regression model, ferritin was the best predictor of bone marrow iron stores (AUC=0.891), outperforming RET-He and %HYPER-He (AUC=0.736 and AUC=0.722, respectively). In a combined model, ferritin/MicroR index achieved the highest diagnostic accuracy (AUC=0.915), outperforming sTfR/log ferritin index (AUC=0.855).

CONCLUSIONS

While single automated red cell parameters did not show improved diagnostic accuracy when compared to traditional iron biomarkers, a novel index ferritin/MicroR has the potential to outperform ferritin and sTfR/log ferritin index for predicting bone marrow iron stores. Further research is needed for interpretation and implementation of novel parameters and indices, especially in the context of unexplained anaemia and myelodysplastic syndromes.

Improving the diagnosis of myelodysplastic syndrome by red blood cell parameters

PURPOSE

To investigate the value of red blood cell parameters in Myelodysplastic syndrome (MDS) diagnosis and their relations to MDS subtypes and risk groups.

METHODS

The red blood cell parameter [mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and red cell distribution width (RDW)] levels [203 MDS, 99 aplastic anemia (AA), 145 megaloblastic anemia (MA)] were collected from a single-center retrospective cohort. The cut-off values, area under the receiver operating characteristic curve (ROC) curve (AUC), sensitivity and specificity of the four parameters were calculated from the ROC. Furthermore, Kruskal-Wallis test and Dunn's Test were performed to determine erythrocyte parameters in different subtypes and prognostic risks MDS.

RESULTS

There are significant statistic differences in RDW (P < 0.001), MCH (P = 0.036) and MCHC (P < 0.001) (MDS vs AA); RDW (P = 0.009), MCV (P < 0.001), MCH (P < 0.001) and MCHC (P = 0.001) (MDS vs MA); MCV (P = 0.011) and MCH (P = 0.008) (higher-risk MDS vs lower-risk MDS). Between MDS and MA, the area under the receiver operating characteristic curve (ROC) curve (AUC) values of MCV, MCH, MCHC, RDW were 0.846, 0.855, 0.617, and 0.593. Between MDS and AA, the AUC values of MCH, MCHC, RDW were 0.609, 0.671, and 0.662, respectively.

CONCLUSIONS

The red blood cell parameters contribute to the differential diagnosis of MDS, AA and MA and are related to MDS subtypes and risk groups.

Impaired Terminal Erythroid Maturation in β0-Thalassemia/HbE Patients with Different Clinical Severity

Anemia in β-thalassemia is associated with ineffective erythropoiesis and a shortened lifespan of erythroid cells. The limited differentiation of β-thalassemic erythroblasts has been documented, but the characteristic feature of terminal erythroid maturation and its physiological relevance are not clearly described in β-thalassemias. Here, the red blood cell and reticulocyte cellular characteristics were determined in patients with β⁰-thalassemia/HbE in comparison to patients with iron deficiency anemia and healthy normal subjects. Severely affected β⁰-thalassemia/HbE patients showed the highest increase in immature reticulocytes, but the number of total erythrocytes was the lowest. Despite similar ranges of hemoglobin levels, β⁰-thalassemia/HbE patients had a higher number of reticulocytes and a greater proportion of immature fraction than patients with iron deficiency anemia did. In vitro CD34⁺ hematopoietic progenitor cells' culture and flow cytometry analysis were conducted to investigate the erythroid maturation and mitochondrial clearance in β⁰-thalassemia/HbE erythroid cells as compared to normal cells. The delayed erythroid maturation and evidence of impaired mitochondria clearance were observed in β⁰-thalassemia/HbE cells at the terminal stage of differentiation. Additionally, increased transcript levels of genes related to erythroid mitophagy, BNIP3L and PINK1, were revealed in β⁰-thalassemia/HbE erythroblasts. The findings indicate that the erythroid maturation is physiologically relevant, and that the restoration of terminal maturation represents a potential therapeutic target for β-thalassemias.

Utility of reticulocyte indices in the diagnosis of pancytopenia

Introduction:

Pancytopenia is a hematological condition in which there is a reduction in all three cell lines of blood. This study aims to evaluate the utility of reticulocyte indices such as reticulocyte % (retic %), immature reticulocyte fraction (IRF), and mean reticulocyte volume (MRV) in identifying the cause of pancytopenia.

Materials and Methods:

Reticulocyte indices were measured by an automated coulter. These values were then correlated with relevant biochemical and bone marrow results and cases were stratified into different etiological groups. Receiver operator curve (ROC) analysis was performed and various cut-off values were derived based on the reticulocyte indices. ROC was repeated to further classify cut-off values at every level to help formulate a diagnostic algorithm.

Results:

A total of 154 cases of pancytopenia were obtained. Ages ranged from 7 months to 87 years with a mean of 42, the male:female ratio was 1.08:1. The majority of the cases were megaloblastic anemias in which the cut-off values for retic % was <0.91 with a sensitivity of 78.1% and specificity of 70%, IRF was 0.45 with a sensitivity of 76.7% and specificity of 64%, and MRV was >121.8 fl with a sensitivity of 83.6% and specificity of 80%. The values on ROC could segregate nutritional from nonnutritional causes. The IRF and MRV also helped to differentiate megaloblastic anemia from dual deficiency anemia.

Conclusion:

Reticulocyte indices help identify the cause of pancytopenia. They can segregate nutritional anemia from other causes of pancytopenia allowing presumptive treatment to be initiated and may obviate invasive procedures such as bone marrow examination.

Complete blood count and cell population data parameters from the Abbott Alinity hq analyzer are useful in differentiating myelodysplastic syndromes from other forms of cytopenia

INTRODUCTION

Myelodysplastic syndromes (MDS) are characterized by morphologic dysplasia and cytopenia and have a propensity for acute leukemic transformation. However, dysplasia is diagnosed by morphology, thus having cell population data (CPD) that can differentiate cytopenic patients with MDS from other conditions may facilitate accurate diagnosis. We assessed the utility of complete blood count (CBC) parameters and CPD derived from an Abbott Alinity hq analyzer to discriminate MDS-related cytopenia.

METHODS

The patient cohort (n = 345) included 64 samples from patients with MDS, 162 from patients with other cytopenia, and 119 from healthy controls. The hematological parameters and research use-only parameters of the Abbott Alinity hq analyzer were compared between the cytopenic groups. The effectiveness of the individual standard and research CBC parameters to differentiate MDS from other forms of cytopenia was assessed through a receiver operating characteristics (ROC) analysis.

RESULTS

The percentage of MAC (Macrocytic RBCs) and hemoglobin distribution width (HDW) were higher in the MDS group than in the other cytopenia group and showed the greatest difference between both groups, with an area under the curve (AUC) of 0.766 (0.678-0.855) and 0.786 (0.702-0.870), respectively. The platelet distribution width was higher in the MDS group than in the other cytopenia group, with an AUC of 0.697 (0.623-0.770). WBC CPD extracted from histograms, especially Atyp-PMN-loc and Neu-ALL-M, showed high AUCs of 0.815 (0.750-0.879) and 0.778 (0.711-0.845), respectively.

CONCLUSION

Our findings demonstrate the clinical utility of CPD and hematology parameters of the Abbott Alinity hq analyzer in the differential diagnosis of MDS.

Short- and medium-term biological variation estimates of red blood cell and reticulocyte parameters in healthy subjects

Background:

The integrated evaluation of traditional and innovative red blood cell (RBC) and reticulocyte parameters is a rapid, inexpensive and non-invasive diagnostic tools for differential diagnosis and follow-up of anemia and other pathological conditions needing bone marrow erythropoiesis assessment. Therefore, estimating the biological variation (BV) of these parameters is essential for evaluating the analytical performance of hematological analyzers, and for enabling accurate data interpretation and appropriate clinical management. This study aims to define short- and medium-term BV estimates and reference change value (RCV) of RBC and reticulocyte parameters.

Methods:

Twenty-one healthy volunteers participated in the assessment of medium-term BV (blood sampling once/week, five consecutive weeks) and 22 volunteers in the assessment of short-term BV (blood sampling once/day, five consecutive days) using Sysmex XN. Outlier analysis was performed before CV-ANOVA, to determine BV estimates with confidence intervals (CI).

Results:

Medium- and short-term within-subject BV were between 0.3% and 16.4% and 0.2%–10.4% (MCH and IRF), respectively, whereas medium and short-term between-subjects BV ranged between 0.9% and 66.6% (MCHC and Micro-R) and 1.4%–43.6% (MCHC and IRF), respectively. The RCVs were similar for all parameters in both arms of the study, except for hemoglobin, RDW-CV and MCV.

Conclusions:

This study allowed for estimating the BV of many RBC and reticulocyte parameters, some of which have not been currently explored. For RBC, hemoglobin, RDW-CV and MCV it seems advisable to use RCV calculated according to monitoring time and/or differentiated by sex. As regards analytical goals, we suggest using the most stringent targets found in the short-term arm of this study.

Laboratory diagnosis of anemia: are the old and new red cell parameters useful in classification and treatment, how?

INTRODUCTION

Anemia is a global problem affecting the population in both developing and developed countries, and there is a debate on which hemoglobin level limit should be used to define anemia in general population and particularly in the elderly. We present herein a laboratory approach to diagnosing the possible causes of anemia based on traditional and new erythroid parameters. In this article, we provide practical diagnostic algorithms that address to differential diagnosis of anemia. Based on both morphological and kinetic classifications, three patterns were considered: microcytic, normocytic, and macrocytic.

METHODS

Main interest is on the clinical usefulness of old and new parameters such as mean cell volume (MCV), red blood cell distribution width (RDW), hypochromic and microcytic erythrocytes, immature reticulocyte fraction (IRF), and some reticulocyte indices such as reticulocyte hemoglobin content and mean reticulocyte volume. The pathophysiologic basis is reviewed in terms of bone marrow erythropoiesis, evaluated by reticulocyte count (increased or normal/decreased) and IRF. The utility of reticulocyte indices in the diagnosis of iron-deficient erythropoiesis (absolute or functional) and in monitoring of response to treatment in nutritional anemia (iron and cobalamin) was also investigated.

RESULTS

For each parameter, the availability, the possible clinical applications, and the limitations were evaluated. A discussion on intraindividual biological variation and its implication on the usefulness of conventional reference intervals and in longitudinal monitoring of the patients was also reported.

CONCLUSION

Red cell parameters and reticulocyte indices play an essential role in differential diagnosis of anemia and in its treatment. More efforts are needed in harmonizing parameters whose results are still too different when produced by different analyzers.

Biological Variations of Hematologic Parameters Determined by UniCel DxH 800 Hematology Analyzer

Context.—The Coulter DxH 800 hematology analyzer can determine conventional hematologic parameters. It also provides many new hematologic parameters, some of which show potential clinical utility.

Objectives.—To study, for the first time, the biological variations of new hematologic parameters and reinvestigate the biological variations of conventional hematologic parameters using the newest Coulter hematology analyzer.

Design.—Forty adult volunteers (21 women and 19 men) were included. All participants maintained their normal lifestyles. Blood samples were drawn in duplicate by a single experienced phlebotomist and analyzed within 2 hours using a single analyzer. Before each batch analysis, the instrument quality controls were performed using the same lots of reagents.

Results.—Within-subject and between-subject biological variations for the conventional hematologic parameters were compatible with published data. The analytic variation of the DxH 800 for these parameters appeared smaller. Index of individuality (ratio of within-subject to between-subject biological variation) for all parameters was low. In addition, intraday and interday biological variations of most parameters studied are fairly constant among the population examined.

Conclusions.—These observations are clinically valuable. Data on within-subject biological variation and analytic precision may be used to generate objective delta-check values for use in quality management. Comparing within-subject and between-subject biological variation on new parameters may allow us to decide the utility of traditional population-based reference ranges. Furthermore, documentation of biological variations of new parameters is an essential prerequisite in the development of any clinical application in the future.

Clinical utility of flow cytometry in the study of erythropoiesis and nonclonal red cell disorders

Erythropoiesis involves proliferation and differentiation of small population of hematopoietic stem cells resident in the bone marrow into mature red blood cells. The determination of the cellular composition of the blood is a valuable tool in the diagnosis of diseases and monitoring of therapy. Flow cytometric analysis is increasingly being used to characterize the heterogeneous cell populations present in the blood and the hematopoietic cell differentiation and maturation pathways of the bone marrow. Here we discuss the role of flow cytometry in the study of erythropoiesis and nonclonal red blood cell disorders. First, we discuss flow cytometric analysis of reticulocytes. Next, we review salient quantitative methods that can be used for detection of fetal-maternal hemorrhage (FMH). We also discuss flow cytometric analysis of high hemoglobin F (HbF) in Sickle Cell Disease (SCD), hereditary spherocytosis (HS), red cell survival and red cell volume. We conclude by discussing cell cycle of erythroid cells.

[Clinical significance of reticulocyte maturation parameters in the differential diagnosis of macrocytic anemias]

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<0.01). MDS showed higher values of reticulocyte maturation parameters including IRF, MRV and MSCV than MA-CLD (P<0.01). IRF and MRV were significantly lower in MA-CLD than in both MA and MDS (P<0.01). MSCV was significantly higher in MDS than in MA (P<0.01).

CONCLUSIONS

This study indicates that the measurement of reticulocyte maturation parameters may be a useful tool in the differential diagnosis of macrocytic anemia. The presence of high values of IRF (> 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.

Effect of hydroxyurea on immature reticulocyte fraction in sickle cell anemia

Immature reticulocyte fraction (IRF) is a good indicator of bone marrow erythropoiesis in response to hemolysis or tissue hypoxia and is markedly increased in sickle cell disease (SS). We compared IRF changes in SS patients with those who were treated with hydroxyurea (SS-HU), and those who had concurrent alpha globin gene deletion (SS-(- deletion). Forty-two patients including 16 SS, 16 SS-HU, and 10 SS-alpha-deletion patients were studied. Significant decreases (P <.01) in reticulocyte indices including IRF, the reticulocyte percentage, and absolute reticulocyte count (ARC) were observed in SS-alpha-deletion compared to SS patients. On the other hand, although the reticulocyte percentage (P <.01) and ARC (P <.01) were significantly decreased in SS-HU compared with SS patients, the IRF was persistently elevated in both groups (P = .4), suggesting continuous bone marrow stimulation in SS-HU patients in response to tissue hypoxia. The possible underlying physiological mechanisms are discussed.

Stability of blood cell counts, hematologic parameters and reticulocytes indexes on the Advia A120 hematologic analyzer

Delayed sample analysis is not a rare circumstance in clinical and laboratory practice, especially when blood samples are shipped to distant centralized laboratories, when the analysis can not be readily performed, or when retesting is appropriate. In this study we sought to evaluate the stability of conventional and new hematologic parameters in blood specimens stored for as long as 24 hours at 4 degrees C. Of the 21 hematologic parameters tested with the use of the Advia 120 hematologic analyzer (Bayer Diagnostics), means for paired samples of specimens differed significantly over the 24-hour storage period for hematocrit, main corpuscular volume, percentage of macrocytes, platelet count, main platelet volume, reticulocyte count and percentage, and reticulocyte hemoglobin content (all P < .01). We noted no significant changes in the other parameters tested or in the white blood cell differential. The overall distribution of the immature reticulocytes fractions remained substantially unchanged, though the high staining-intensity fraction showed a considerable shift from the baseline measure. Bland-Altman plots and limits-of-agreement analysis showed mean biases between -4.8% and 37.2% and relative coefficients of variations ranging from 0.4% to 32.7%. The 95% agreement interval in the set of differences was satisfactory and almost within the current analytic-quality specifications for desirable bias. The results of this investigation suggest that, within certain limitations for parameters derived or calculated from cellular volumes, blood specimens stored for as long as 24 hours at 4 degrees C may be suitable for hematologic testing.

Pharmacodynamic Analysis of Changes in Reticulocyte Subtype Distribution in Phlebotomy-Induced Stress Erythropoiesis

Changes in the reticulocyte subtype distribution (high, medium and low reticulocytes count (HR, MR, LR)) measured by flow cytometry following phlebotomy-induced stress erythropoiesis (abruptly dropping hemoglobin to 3-4 g/dl over 4-5 hr) and the pharmacodynamic (PD) relationship to the stimulated erythropoietin (EPO) was investigated in sheep. A PD model was developed that describes the relationship between EPO and the reticulocyte maturity distribution fractions (r=0.95+/-0.02, mean +/- SD). The lag-time between EPO activation of erythroid progenitor cells and the subsequent increase in the least mature HR fraction in the peripheral circulation was 0.72 +/- 0.08 days. The mean transition times (in days) for all three reticulocyte fractions changed at baseline from, T(HR) : 0.09 +/- 0.06, T(MR) : 0.06 +/- 0.04, and T(LR) : 0.46 +/- 0.24 to T(HR) : 0.13 +/- 0.08, T(MR) : 0.29 +/- 0.15, and T(LR) : 2.3 +/- 0.24 under stress erythropoiesis. The total mean residence time for a reticulocyte in the peripheral circulation, T(total) (T(HR) + T(MR) + T(LR)), increased from 0.60 +/- 0.33 days under basal to 2.8 +/- 0.09 days during stress erythropoiesis. The statistically significant increase observed for T(LR) and T(total) supports the hypothesis that stress erythropoiesis perturbs the mean reticulocyte transition times. A correlation analysis between various new, proposed metrics involving the HR, MR and LR fractions and the total reticulocyte count, with the latter indicative of stress erythropoiesis at higher total counts, revealed a highly significant correlation indicating these new metrics may be a valuable adjunct to the reticulocyte maturation index (RMI) and the immature reticulocyte fractions index (IRF) previously used in assessing erythropoietic activity in response to anemia.