New erythrocyte and reticulocyte parameters on CELL-DYN Sapphire: analytical and preanalytical aspects

Anemia of chronic diseases: current state of the problem and perspectives

Anemia of chronic diseases is a condition, that accompanies several chronic conditions, that have inflammation as an underlying cause. The article covers current concepts of pathogenesis, evaluation and treatment of this type of anemia. The new perspectives in the development of investigational methods and treatment are discussed. The new methods of iron deficiency assessment in patients with systemic inflammation are discussed separately.

Iron imbalance in cancer: Intersection of deficiency and overload

Iron, an essential trace element, plays a complex role in tumour biology. While iron causes cancer clearance through toxic free radical generation, iron‐induced free radical flux also acts as a cancer promoter. These fates majorly guided through cellular response towards pro‐oxidant and antioxidant settings in a tumour microenvironment, designate iron‐induced oxidative stress as a common yet paradoxical factor in pro‐tumorigenesis as well as anti‐tumorigenesis, posing a challenge to laying down iron thresholds favouring tumour clearance. Additionally, complexity of iron's association with carcinogenesis has been extended to iron‐induced ROS's involvement in states of both iron deficiency and overload, conditions identified as comparable, inevitable and significant coexisting contributors as well as outcomes in chronic infections and tumorigenesis. Besides, iron overload may also develop as an unwanted outcome in certain cancer patients, as a result of symptomatic anaemia treatment owed to irrational iron‐restoration therapies without a prior knowledge of body's iron status with both conditions synergistically acting towards tumour aggravation. The co‐play of iron deficiency and overload along with iron's pro‐tumour and antitumour roles with intersecting mechanisms, thus presents an unpredictable regulatory response loop in a state of malignancy. The relevance of iron's thresholds beyond which it proves to be beneficial against tumorigenesis hence becomes questionable. These factors pose a challenge, over establishing if iron chelation or iron flooding acts as a better approach towards antitumour therapies. This review presents a critical picture of multiple contrasting features of iron's behaviour in cancer, leading towards two conditions lying at opposite ends of a spectrum: iron deficiency and overload in chronic disease conditions including cancer, hence, validating the critical significance of diagnosis of patients' iron status prior to opting for subsequent therapies.

Parameters of the complete blood count predict in hospital mortality

INTRODUCTION

Mortality rates are used to evaluate the quality of hospital care after adjusting for disease severity and, commonly also, for age, comorbidity, and laboratory data with only few parameters of the complete blood count (CBC).

OBJECTIVE

To identify the parameters of the CBC that predict independently in-hospital mortality of acutely admitted patients.

POPULATION

All patients were admitted to internal medicine, cardiology, and intensive care departments at the Laniado Hospital in Israel in 2018 and 2019.

VARIABLES

Independent variables were patients' age, sex, and parameters of the CBC. The outcome variable was in-hospital mortality.

ANALYSIS

Logistic regression. In 2018, we identified the variables that were associated with in-hospital mortality and validated this association in the 2019 cohort.

RESULTS

In the validation cohort, a model consisting of nine parameters that are commonly available in modern analyzers had a c-statistics (area under the receiver operator curve) of 0.86 and a 10%-90% risk gradient of 0%-21.4%. After including the proportions of large unstained cells, hypochromic, and macrocytic red cells, the c-statistic increased to 0.89, and the risk gradient to 0.1%-29.5%.

CONCLUSION

The commonly available parameters of the CBC predict in-hospital mortality. Addition of the proportions of hypochromic red cells, macrocytic red cells, and large unstained cells may improve the predictive value of the CBC.

The effect of reticulocyte hemoglobin content on the diagnosis of iron deficiency anemia: A meta-analysis study

Background

Iron deficiency anemia (IDA) is the most common type of anemia worldwide and has many adverse effects on life quality. This meta-analysis study aims to show that reticulocyte hemoglobin content (CHr) is more effective than routinely used parameters in the diagnosis of IDA.

Methods

Comprehensive and systematic research was done using international databases including PubMed, Web of Science, Cochrane Library, Science Direct, and Google Scholar, which contain all articles published on IDA until December 29, 2020. Seventeen articles were included in the meta-analysis.

Results

The analyses found the Cohen's deffect size (Standardized Mean Difference) values of the parameters. Accordingly, CHr is 2.84 (95% CI 2.36 to 3.31), mean corpus volume (MCV) is 2.46 (95% CI 1.97 to 2.95), ferritin is 2.37 (95% CI 1.63 to 3.11), and transferrin saturation (TSAT) is 3.76 (95% CI 2.14 to 5.38). To diagnose IDA, the sensitivity value of the CHr concentration was found as 83.5% (95% CI 76.1 to 89.8), specificity value to be 91.8% (95% CI 85.5 to 96.4), and mean cut-off value as 28.2 pg.

Conclusions

The results of our study reveal the findings that CHr is a better biomarker than MCV and ferritin used in determining IDA, and its efficacy is lower than TSAT. It is very important to use it routinely for the pre-diagnosis of IDA, which is very important for public health. The groups in the study are heterogeneous but contain bias. Therefore, meta-analyses of studies with less heterogeneity of CHr are needed.

The Relationship Between the Severity of Coronary Artery Disease and Erythrocyte Morphology Parameters Measured by New-Generation Hematology Analyzer

BACKGROUND

There is a possible relation between red blood cell distribution width (RDW) and various clinical conditions. These conditions can render RDW disadvantageous in its relation with cardiovascular disease. There may be a relation between the severity of acute coronary syndrome (ACS) and the percentage of hypochromia (hypo%), percentage of hyperchromia (hyper%), percentage of macrocytosis (MAC%), and percentage of microcytosis (MIC%) values measured using new-generation hematological devices.

OBJECTIVE

We aimed to examine the relation between the SYNTAX score and the hypo%, hyper%, MAC%, and MIC% values in patients admitted with ACS.

METHOD

A group of 55 patients who underwent coronary angiography with diagnosis of ACS (STEMI and NSTEMI) and a control group of 48 patients with normal coronary arteries were included in the study. Venous blood samples were collected in the morning after a fasting of at least 8 h and analyzed using standard laboratory methods. Hemogram parameters were studied using Alinity HQ (Abbott, USA) a completely automated hemogram autoanalyzer. Biochemical parameters were studied using Architect c16000 (Abbott, USA) a completely automated biochemistry autoanalyzer.

RESULTS

Significant difference was observed in erythrocyte morphology-related tests (mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, RDW, hypo%, hyper%, MIC%, and MAC%) between the groups. Correlation analysis showed a positive correlation between the SYNTAX score and MAC% (r = 0.315, p = 0.019). Multivariate logistic regression analysis was performed for MAC% to identify the independent predictors of the SYNTAX score (β = 0.315, p = 0.019).

CONCLUSION

Changes in MAC% test can be measured in emergencies with new-generation hematological devices and used as independent predictors of presence of severe coronary artery disease.

Red Blood Cells and Platelets Conventional and Research Parameters: Stability Remarks Before Their Interpretation

OBJECTIVES

To analyze the stability of red blood cells, platelets, and reticulocytes of the research parameters, in combination with the respective conventional parameters, for each analyte; and to quantify the morphological changes in these analytes, to propose a correction factor for each.

METHODS

Ethylenediaminetetraacetic acid (EDTA) blood specimens from patients were reanalyzed in 2-hour intervals and then, the mean percentage (X¯t%) changes were calculated. To evaluate the stability of the analyzed material, we used different criteria according to within-run and between-batch analytical variation, as well as intraindividual biological variation. Next, the mean deviation percentage of the parameters that undergo time-dependent significant changes was calculated, to obtain a correction factor.

RESULTS

Several conventional and research parameters showed significant alterations in the stability at an early time after arrival at the laboratory.

CONCLUSION

Cell variations over time can be quantified and corrected by applying a multiplying factor to the signal obtained in the analyzer.

Stability of New Erythrocyte and Reticulocyte Parameters in Testing for Anemia on the Sysmex XN 9000

Background

New erythrocyte and reticulocyte parameters provide improved classification of anemia and monitoring of erythropoeitic activity. Parameters available on the Sysmex XN analyzers include the percentage of microcytic red blood cells (%Micro-R), percentage of macrocytic red blood cells (%Macro-R), percentage of hypochromic red blood cells (%Hypo-He), percentage of hyperchromic red blood cells (%Hyper-He), reticulocyte hemoglobin content (Ret-He), and immature reticulocyte fraction (IRF). However, use of these parameters is limited by specimen stability.

Methods

To verify the stability of the new erythrocyte and reticulocyte parameters during prolonged storage, 20 blood specimens were analyzed on the Sysmex XN-9000 hematology analyzer. The specimens included healthy patients (60%) and patients with anemia (40%). The specimens were stored at room temperature (RT) and at 4° to 8°C. Analysis was performed after 12, 24, 48, and 72 hours of storage.

Results

Reticulocyte parameters IRF and Ret-He were precise and stable for at least 72 hours after collection when stored at RT and 4° to 8°C. The volume-dependent parameters, %Macro-R and %Micro-R, were stable for less than 12 hours after collection at RT (mean [SD%], 6.55 [3.19%] and -20.70 [10.37%], respectively). Storage at 4° to 8°C showed a reduction in osmotic swelling. However, %Macro-R and %Micro-R were stable for less than 12 hours after collection (mean [SD%], 4.89 [2.02%] and -17.17 [8.38%], respectively). Similarly, %Hypo-He showed a mean (SD%) increase of 0.73 (4.05%) and %Hyper-He showed a decrease of -0.70 (9.72%) at less than 12 hours after storage at 4° to 8°C.

Conclusion

New reticulocyte parameters stored at RT and 4° to 8°C are suitable for testing on the Sysmex XN analyzer.

Reticulocyte hemoglobin content (MCHr) in the detection of iron deficiency

BACKGROUND

Blood hemoglobin (Hb) concentration within the reference interval does not exclude iron deficiency (ID): individuals with normal stores lose iron during a long period before their Hb falls below of the level that is defined as anemia. The process entails a decrease of storage iron, shown by serum ferritin below reference range, followed by iron depletion, eventually leading to iron restricted erythropoiesis; consequence of an imbalance between erythropoietic iron requirements and too low supply is a reduction of Hb synthesis in reticulocytes.

OBJECTIVE

We study the potential utility of mean reticulocyte hemoglobin content (MCHr), reported by CELL-DYN Sapphire (Abbott Diagnostics) analyzer, in the detection of ID in non-anemic adults.

METHODS

207 patients with Hb within the reference range were enrolled. ID was defined as Hb>120g/L (women), >130g/L (men) and serum ferritin <30μg/L. Student's t-test was applied to detect deviations between groups, statistical significance P<0.05. The performance of MCHr in detecting ID was evaluated applying Receiver Operating Characteristic (ROC) curve analysis. Kappa test was applied to verify concordance between ferritin and MCHr.

RESULTS

68 patients (33%) suffered ID, median MCHr in this group was 26.9 pg, statistically different from the normal group, MCHr 30.9pg (P<0.0001). ROC ANALYSIS (GOLD STANDARD FERRITIN <30μG/L): Area under curve AUC 0.851 (95% CI 0.770-0.912) at cut off 30.0 pg, with sensitivity 84.1% and specificity 71.1%. Kappa 0.667 (95% CI 0.527-0.858).

CONCLUSION

Due to their short lifespan reticulocytes and derived parameters reflect current erythropoiesis status, before Hb and erythrocyte indices drop. MCHr had the best AUC and diagnostic value compared to erythrocyte indices. MCHr is a reliable test for the investigation of ID and could improve the detection of iron deficient adults.

Usefulness of Reticulocyte Parameters for Diagnosis of Hereditary Spherocytosis in Children

Innovations in laboratory equipment have enabled a widening of the spectrum of hematological parameters obtained from single measurements of peripheral blood samples, including reticulocyte parameters. The usefulness of reticulocytes indices to confirm the diagnosis of pediatric anemia was analyzed in this study. The study group consisted of 163 children, aged 1 month-17 years, with anemia. Complete blood count extended with an analysis of reticulocyte parameters were measured using a Beckman Coulter LH 750. The mean sphered corpuscular volume (MSCV) in the group of children with hereditary spherocytosis (HS) was 66.71 ± 8.45 fL, whereas in other anemic patients MSCV was 87.76 ± 11.22 fL, p < 0.0001. In HS children the average mean corpuscular volume of red blood cells was higher than the MSCV value, while an inverse correlation was observed in the group of children with other anemias, p < 0.0001. A significant difference was found between the ratio of absolute reticulocyte count and IRF fraction (Ret#/IRF)-0.6 ± 0.28 in the HS group and 0.23 ± 0.16 in the non-HS group, respectively. Our results suggest that analysis of reticulocyte parameters is useful in the diagnosis of anemia and should be included in the routine CBC analysis in anemic children.

Evaluation of the Efficiency of the Reticulocyte Hemoglobin Content on Diagnosis for Iron Deficiency Anemia in Chinese Adults

Our aim was to evaluate the cut-off value and efficiency of using reticulocyte hemoglobin content as a marker to diagnose iron deficiency anemia in Chinese adults. 140 adults who needed bone marrow aspiration for diagnosis at the hematology department of the Peking Union Medical College Hospital were enrolled according to the inclusive and exclusive criteria. Venous blood samples were collected to detect complete blood count, including hemoglobin, reticulocyte hemoglobin content, hematocrit, mean cellular volume, corpuscular hemoglobin concentration, hemoglobin content, free erythrocyte protoporphyrin; iron indexes of serum ferritin, serum transferrin receptor, and unsaturated iron-binding capacity; and inflammation markers of C-reactive protein and α-acid glycoprotein. Bone marrow samples were obtained for the bone marrow iron staining, which was used as the standard for the evaluation of iron status in this study. Subjects were divided into three groups according to hemoglobin levels and bone marrow iron staining results: the IDA (iron deficiency anemia) group, the NIDA (non-iron deficiency anemia) group, and the control group. The differences of the above-mentioned indexes were compared among the three groups and the effect of inflammation was also considered. The cut-off value of reticulocyte hemoglobin content was determined by receiver operation curves. The IDA group (n = 56) had significantly lower reticulocyte hemoglobin content, mean cellular volume, corpuscular hemoglobin concentration, hemoglobin content, and serum ferritin; and higher free erythrocyte protoporphyrin, unsaturated iron-binding capacity, and serum transferrin receptor (p < 0.05) compared with the NIDA group (n = 38) and control group (n = 46). Hematocrit, serum ferritin, and unsaturated iron-binding capacity were significantly affected by inflammation while reticulocyte hemoglobin content and other parameters were not. The cut-off value of reticulocyte hemoglobin content for diagnosing iron deficiency anemia was 27.2 pg, with a sensitivity of 87.5% and a specificity of 92.9%. The cut-off values for mean cellular volume, serum ferritin, and serum transferrin receptor were 76.6, 12.9, and 4.89 mg/L, respectively. Reticulocyte hemoglobin content had the largest area under the curve of 0.929, while those for mean cellular volume, serum ferritin, serum transferrin receptor were 0.922, 0.887, and 0.900, respectively. Reticulocyte hemoglobin content has a high sensitivity and specificity in the diagnosis of iron deficiency anemia, and its comprehensive diagnostic efficacy is better than other traditional indicators-such as serum ferritin and serum transferrin receptor.

Red Cell Cytogram in CELL-DYN® Sapphire: A Ready-to-Use Function for Recognizing Thalassemia Trait

Single-cell optical analysis of red blood cells provides information on the cellular hemoglobin concentration and volume of red cells. We evaluated the reliability of the typical profiles of the cytogram hemoglobin concentration/ volume (Mie Map), produced by the CELL-DYN® Sapphire analyzer (Abbott Diagnostics, Santa Clara, CA, USA) in the discrimination of iron deficiency anemia (IDA) and thalassemia trait. A total of 380 patients with microcytic anemia were studied: 220 with IDA, 101 β-thalassemia trait, 30 β-thalassemia trait with concomitant iron deficiency, 29 α-thalassemia trait. Three professionals reviewed the Mie maps, with no information regarding the disease of the patient. The observers made a presumptive diagnosis (genetic or acquired anemia) and the percentages of correct classifications were recorded. IDA showed broad shaped shift of the cytogram while carriers presented narrow clustering in the lower microcytic area: 100 % IDA were correctly classified and 96–82% of carriers were recognized. Visual inspection of the Mie map reveals different profiles in IDA and thalassemia trait; those patterns are in concordance with the numerical data Mie map helps in the evaluation of large amounts of data.

Verification and standardization of blood cell counters for routine clinical laboratory tests

The use of automated blood cell counters (automated hematology analyzers) for diagnostic purposes is inextricably linked to clinical laboratories. However, the need for uniformity among the various methods and parameters is increasing and standardization of the automated analyzers is therefore crucial. Standardization not only involves procedures based on reference methods but it also involves validation, verification, quality assurance, and quality control, and it includes the involvement of several participants. This article discusses the expert guidelines and provides an overview of issues involved in complete blood count parameter reference methods and standardization of reporting units.

Biomarkers of hypochromia: the contemporary assessment of iron status and erythropoiesis

Iron status is the result of the balance between the rate of erythropoiesis and the amount of the iron stores. Direct consequence of an imbalance between the erythroid marrow iron requirements and the actual supply is a reduction of red cell hemoglobin content, which causes hypochromic mature red cells and reticulocytes. The diagnosis of iron deficiency is particularly challenging in patients with acute or chronic inflammatory conditions because most of the biochemical markers for iron metabolism (serum ferritin and transferrin ) are affected by acute phase reaction. For these reasons, interest has been generated in the use of erythrocyte and reticulocyte parameters, available on the modern hematology analyzers. Reported during blood analysis routinely performed on the instrument, these parameters can assist in early detection of clinical conditions (iron deficiency, absolute, or functional; ineffective erythropoiesis, including iron restricted or thalassemia), without additional cost. Technological progress has meant that in recent years modern analyzers report new parameters that provide further information from the traditional count. Nevertheless these new parameters are exclusive of each manufacturer, and they are patented. This is an update of these new laboratory test biomarkers of hypochromia reported by different manufactures, their meaning, and clinical utility on daily practice.

Reference intervals of extended erythrocyte and reticulocyte parameters

Optical analysis of erythrocytes can provide information on the hemoglobin concentration and content of reticulocytes and mature erythrocytes. Such parameters have proven clinical utility in anemia diagnosis and therapy monitoring. For interpretation, reliable reference ranges are needed. The aim of this study was to establish reference intervals for extended erythrocyte and reticulocyte parameters as measured with the Abbott CELL-DYN Sapphire hematology analyzer. Secondary aims were to study sample stability and to investigate gender- and age dependency of the reference ranges.

Extended RBC parameters were measured in routine samples of a primary health care laboratory. The study cohort included 8161 samples of unique individuals, which were analyzed using Bhattacharya statistics. As a comparison, reference intervals were calculated in a subset of individuals without iron depletion.

The majority of erythrocyte and reticulocyte para\xadmeters were normally distributed, allowing calculation of reference intervals. Only for hypo- and hyperchromic erythrocytes non-parametric statistics had to be used. The reference range for mean cellular hemoglobin content of reticulocytes (MCHr) was 28.5–34.5 pg (1.77–2.14 fmol) in the entire study group and 26.0–35.1 pg (1.60–2.17 fmol) in the non iron-depleted subgroup. No differences between sexes were found. Most parameters showed significant age effects in children and adolescents.

Reference intervals have been established for extended RBC and reticulocyte parameters for the CELL-DYN Sapphire. Gender effects could not be demonstrated and age effects were of limited size, except for individuals younger than 18 years. Extended RBC parameters are stable for at least 6 h after blood collection.