Increased mean corpuscular haemoglobin concentration: artefact or pathological condition?

Performance evaluation of the new Sysmex XR-Series haematology analyser

Background

The new XR-Series haematology analyser from Sysmex provides increased throughput and automation, along with a new reagent in WDF channel for optimised WBC differential.

Methods

An analytical performance study for the XR analyser was conducted to evaluate the WDF channel parameters in comparison to the instrument specifications. Additionally, 7460 samples were measured on XR and XN analysers to compare selected parameters and flags, and 930 randomly selected samples were further evaluated with microscopy.

Results

All investigated aspects of the analytical performance study for the XR fell within the manufacturer specifications. The correlation coefficients between the two systems for the parameters tested were greater than 0.983 for the main CBC and DIFF parameters, greater than 0.909 for the Extended Inflammation Parameters, and greater than 0.932 for the parameters used in the workflow rulesets of the Extended IPU. Similarly high sensitivities for the detection of abnormal cells were observed for the 'Blasts/Abn Lympho?' flag (XN: 100%, XR: 99.0%) and WPC abnormal flags ('Blasts?' or 'Abn Lympho?') (XN: 97.0%, XR: 96.0%). XN with WPC channel had a 26% reduction of false positive smears compared to XR with 22% reduction, a statistically non-significant difference.

Conclusion

The XR analyser had very good analytical performance, and highly comparable results to the predecessor XN analyser in all investigated parameters, flags and workflow aspects.

Optimizing the management of analytical interferences affecting red blood cells on XN-10 (Sysmex®)

INTRODUCTION

Interferences on red blood cells (RBCs) measurement and the associated parameters in haematology analyzers are very common. Many sources of interferences are described but their management remains uncertain depending on the measurement system; we aimed at developing an optimized scheme allowing the accurate management of most interferences affecting RBCs, based on the alternative "optical" parameters from SYSMEX XN-10.

METHODS

Samples from 12 groups of relevant interferences were analysed and compared with a control group allowing (1) the determination of deviation thresholds beyond which an interference is likely, and (2) the development of two flowcharts for their subsequent management. These flowcharts were then evaluated among a bank of retrospective typical cases of interferences and in the routine flow of the laboratory.

RESULTS

After verifying the excellent agreement between standard and alternative parameters, the comparative study between analytical channels allowed to determine an acceptable deviation and then discriminate technical concerns caused by cold agglutinins, leukocytosis and plasma-related interferences. This led to the development of flowcharts ensuring the accurate management of these interferences, whether MCHC is <320 or >365 g/L. These proposed flowcharts allowed the correction of 63/65 historical confirmed interferences cases (97%). Furthermore, they corrected 18 results among 901 unselected prospective samples.

CONCLUSION

The resulting flowcharts allow a relevant correction for most common interferences affecting RBCs and are now definitively included in the routine analytical management and will be directly incorporated in the middleware of the laboratory.

Assessment of Reticulocyte and Erythrocyte Parameters From Automated Blood Counts in Vaso-Occlusive Crisis on Sickle Cell Disease

Sickle cell disease is a complex genetic disease involving cell adhesion between red blood cells, white blood cells, platelets and endothelial cells, inducing painful vaso-occlusive crisis (VOC). We assessed reticulocyte and erythrocyte parameters in a cohort of confirmed SCD patients, and investigated whether a combination of these routine laboratory biomarkers of haemolysis could be used to predict VOC development. Reticulocyte and erythrocyte parameters were evaluated using the Sysmex XN-9000 analyser. A total of 98 patients with SCD were included, 72 in steady state and 26 in VOC. Among the 72 patients in steady state, 22 developed a VOC in the following year (median: 3 months [2-6]). The following parameters were increased in SCD patients with VOC development compared to SCD patients without VOC development in the following year: reticulocyte count (94.6 10⁹/L [67.8-128] vs. 48.4 10⁹/L [24.9-87.5]), immature reticulocyte count (259 10⁹/L [181-334] vs. 152 10⁹/L [129-208]) reticulocyte/immature reticulocyte fraction (IRF) ratio (6.63 10⁹/(L^*%) [4.67-9.56] vs. 4.94 10⁹/(L^*%) [3.96-6.61]), and medium fluorescence reticulocytes (MFR) (19.9% [17.4-20.7] vs. 17.1% [15.95-19.75]). The association of a reticulocyte count of >189.4 10⁹/L and an MFR of >19.75% showed a sensitivity of 81.8% and a specificity of 88% to predict VOC development in the following year. Based on our findings, a combination of routine laboratory biomarkers, as reticulocyte count, immature reticulocyte count and fluorescent reticulocyte fraction at steady state, could be used to predict VOC development in SCD.

Higher Mean Corpuscular Hemoglobin Concentration is Associated with Worse Prognosis of Hepatorenal Syndrome: A Multicenter Retrospective Study

BACKGROUND

Hepatorenal syndrome (HRS) is a severe complication of decompensated cirrhosis with high mortality. However, few prognostic factors have been identified and studies are urgently needed to facilitate precise treatment.

METHODS

Patients with decompensated cirrhosis and acute kidney injury were enrolled from four general hospitals between January 2010 and March 2020. Demographic and laboratory data were compared between surviving and non-surviving patients and also among different levels of HRS severity. COX regression analysis was performed to determine the effect of mean corpuscular hemoglobin concentration (MCHC) on survival of patients with HRS.

RESULTS

Out of a total of 1287 patients enrolled, 325 patients were analyzed. MCHC was significantly higher in non-survivors than in survivors, and in patients with more serious disease, defined as failure of organ systems. The hazard ratio (HR) of mortality was 1.17, 1.18 and 1.11, when adjusted by the crude model, model 1 and model 2, respectively. When MCHC was converted to a categorical variable based on the quartile of MCHC, the HR for the highest quartile of MCHC was 2.11 (95% CI: 1.45-3.06, P <0.05) compared to the lowest quartile of MCHC in the crude model, and when adjusted for age and sex (model 1), the HR was 2.20 (95% CI: 1.52-3.20, P <0.05). In model 2, which was adjusted for complex characteristics, the HR was 1.77 (95% CI: 1.17-2.68, P <0.05). The results of Kaplan-Meier curves were consistent with those from Cox regression analysis.

CONCLUSIONS

Higher MCHC was associated with worse prognosis in HRS.

Prospective validation of an automatic reflex test for identifying spurious elevations of mean corpuscular haemoglobin concentration due to the presence of cold agglutinins

Cold agglutinins (CA) in blood may cause false reduction in red blood cell (RBC) count and false increases of RBC indices, such as mean corpuscular haemoglobin concentration (MCHC). Preheating at 37 °C for 2 h is used to overcome this problem. We previously proposed the integration in a total laboratory automation (TLA) setting of a customized reflex test in the presence of MCHC >385 g/L for identifying spurious elevations due to CA. Here, we prospectively evaluate this approach after its introduction in our clinical practice. We evaluated 73 consecutive blood samples from 34 adult patients. Short heating (<1 min) at 41 °C using the reticulocyte channel of Sysmex XN-9000 platform was followed by calculation of optical parameters by the instrument software to ensure quick solution of the CA-dependent problems. After the reflex test in the reticulocyte channel, MCHC dropped below 385 g/L in 50 samples. The reflex markedly corrected the RBC number in eight samples obtained from three patients with CA condition. Two samples from markedly anaemic patients had low blood haemoglobin and RBC count before and after reflex. The remaining 13 samples were obtained from 12 patients, most of whom were on antiretroviral therapy or suffered severe electrolyte disorders, known conditions associated to increased MCHC. The implementation of the proposed automatic reflex by reticulocyte channel on the Sysmex XN-9000 platform in a TLA setting may solve the problem of spuriously high MCHC due to RBC agglutination for CA in a few minutes instead of waiting hours for sample preheating.

Convenience of Hgb-O detected by optical method in XN-series hematology analyzers in evaluating hemoglobin concentration in samples with chylous turbidity

The chylous turbidity of blood samples is one of the causes of false-high hemoglobin (Hgb) concentration measurements by the colorimetric method, which has been widely applied in hematology analyzers. In such cases, additional manual procedures are required to correct Hgb concentrations. We therefore examined the effectiveness of an optical method for measuring Hgb concentrations in samples with chylous turbidity using Hgb-O in the reticulocyte channel equipped in XN-series analyzers (Sysmex, Kobe, Japan). Hgb-O showed excellent basic performance, including linear correlation and invariability with sodium lauryl sulfate (SLS)-Hgb detected by the colorimetric method. In the analysis of samples from healthy volunteers supplemented with fat emulsion, chylous turbidity did not affect Hgb-O but SLS-Hgb, which was falsely increased according to the dose of fat emulsion. Actually, SLS-Hgb was falsely elevated in 34 of 40 chylous turbidity 3+ samples. The remaining 6 samples were measured in hematology analyzers where Hgb-O was inconsistent with SLS-Hgb in the internal quality control records. For these samples, the correction factors calculated from the internal quality control records could contribute to providing the corrected Hgb-O value. These findings suggested that the optical method was effective and convenient for accurately evaluating Hgb concentrations in samples with extremely chylous turbidity.

The long-term effects of rapamycin-based immunosuppressive protocols on the expression of renal aquaporins 1, 2, 3 and 4 water channels in rats

BACKGROUND

To this day, the effect of multi-drug immunosuppressive protocols on renal expression of AQPs is unknown. This study aimed to determine the influence of rapamycin-based multi-drug immunosuppressive regimens on the expression of aquaporins (AQPs) 1, 2, 3, and 4 in the rat kidney.

METHODS

For 6 months, 24 male Wistar rats were administered immunosuppressants, according to the three-drug protocols used in patients after organ transplantation. The rats were divided into four groups: the control group, the TRP group (tacrolimus, rapamycin, prednisone), the CRP group (cyclosporine A, rapamycin, prednisone), and the MRP group (mycophenolate mofetil, rapamycin, prednisone). Selected red cell indices and total calcium were measured in the blood of rats and quantitative analysis of AQP1, AQP2, AQP3 and AQP4 immunoexpression in the kidneys were performed.

RESULTS

In the TRP and CRP groups, a mild increase of mean corpuscular hemoglobin concentration, hematocrit and total calcium were observed. Moreover, decreased expression of AQP1-4 was found in all experimental groups, with the highest decrease in the CRP group.

CONCLUSIONS

The long-term immunosuppressive treatment using multi-drug protocols decreased AQP1-4 expressions in renal tubules, possibly leading to impaired urine-concentrating ability in rat.

Cold agglutinin disease following SARS-CoV-2 and Mycoplasma pneumoniae co-infections

SARS‐CoV‐2 and other respiratory co‐infections may occur. As Mycoplasma pneumoniae and various viruses can cause cold agglutinin disease (CAD), the presence of CAD in COVID‐19 patients should indicate the need of investigations for those pathogens.

Use of Sysmex XN-10 red blood cell parameters for screening of hereditary red blood cell diseases and iron deficiency anaemia

Introduction

In daily practice in haematology laboratories, red blood cell (RBC) abnormalities are frequent and their management is a real challenge. The aim of this study is to establish a “decision tree” using RBC and reticulocyte parameters from the SYSMEX XN‐10 analyser to distinguish between patients with a hereditary RBC disease from iron deficiency anaemia and other patients.

Methods

We analysed results of complete RBC counts in a cohort composed of 8217 adults divided into 5 different groups: iron deficiency anaemia (n = 120), heterozygous haemoglobinopathy (n = 92), sickle cell disease syndrome (n = 56), hereditary spherocytosis (n = 18) and other patients (n = 7931). A Classification And Regression Tree (CART) analysis was used to obtain a two‐step decision tree in order to predict these previous groups.

Results

Five parameters and the calculated RBC score were selected by the CART method: mean corpuscular haemoglobin concentration, percentage of microcytes, distribution width of the RBC histogram, percentage of nucleated red blood cells, immature reticulocytes fraction and finally RBC Score. When applying the tree and recommended flowchart, 158/166 of the RBC hereditary disease patients and 114/120 iron deficiency anaemia patients are detected. Overall, the correct classification rate reached 99.4%. Sensitivity and specificity for RBC disease detection were 95.2% and 99.9%, respectively. These results were confirmed in an independent validation cohort.

Conclusion

Based on the XN‐10 RBC and reticulocyte parameters, we propose a two‐step decision tree delivering a good prediction and classification of hereditary RBC diseases. These results can be used to optimize additional reticulocyte analysis and microscopy review.

Use of the reticulocyte channel warmed to 41°C of the XN-9000 analyzer in samples with the presence of cold agglutinins

OBJECTIVES

The purpose of this study was to compare data obtained from the reticulocyte channel (RET channel) heated to 41°C with those obtained from impedance channel (I-Channel) at room temperature in the samples with the mean corpuscular hemoglobin concentration (MCHC)<370g/L and in samples with the MCHC>370g/L, in the presence of cold agglutinins.

METHODS

In this study, 60 blood samples (group 1) with the MCHC<370g/L (without cold agglutinins) and 78 blood samples (group 2) with the MCHC>370g/L (with cold agglutinins) were used to compare the two analytical channels of the XN-9000 analyzer in different preanalytical conditions. The parameters evaluated in both groups were the following: red blood cell (RBC), hemoglobin (HGB), hematocrit (HCT), mean cell volume (MCV), RBC-most frequent volume (R-MFV), mean hemoglobin concentration (MCH) and mean cellular hemoglobin concentration (MCHC).

RESULTS

The results of this study showed an excellent correlation with both channels of the XN-9000 analyzer in samples with and without cold agglutinins, except for the MCHC. The bias between the values obtained in the I-channel and those obtained in the RET channel of both groups was insignificant and remained within the limits of acceptability, as reported by Ricos et al. for all considered parameters, except for MCHC.

CONCLUSIONS

The presence of cold agglutinins in blood samples can be detected by a spurious lowering of the RBC count and by a spurious increase in the MCHC. The RET channel represents a great opportunity to correct the RBC count in a rapid manner without preheating. However, neither methodology can completely solve the residual presence of cold agglutinins in all samples, despite the MCHC values being < 370g/L.

Density, heterogeneity and deformability of red cells as markers of clinical severity in hereditary spherocytosis

Hereditary spherocytosis (HS) originates from defective anchoring of the cytoskeletal network to the transmembrane protein complexes of the red blood cell (RBC). Red cells in HS are characterized by membrane instability and reduced deformability and there is marked heterogeneity in disease severity among patients. To unravel this variability in disease severity, we analyzed blood samples from 21 HS patients with defects in ankyrin, band 3, α-spectrin or β-spectrin using red cell indices, eosin-5-maleimide binding, microscopy, the osmotic fragility test, Percoll density gradients, vesiculation and ektacytometry to assess cell membrane stability, cellular density and deformability. Reticulocyte counts, CD71 abundance, band 4.1 a:b ratio, and glycated hemoglobin were used as markers of RBC turnover. We observed that patients with moderate/severe spherocytosis have short-living erythrocytes of low density and abnormally high intercellular heterogeneity. These cells show a prominent decrease in membrane stability and deformability and, as a consequence, are quickly removed from the circulation by the spleen. In contrast, in mild spherocytosis less pronounced reduction in deformability results in prolonged RBC lifespan and, hence, cells are subject to progressive loss of membrane. RBC from patients with mild spherocytosis thus become denser before they are taken up by the spleen. Based on our findings, we conclude that RBC membrane loss, cellular heterogeneity and density are strong markers of clinical severity in spherocytosis.

Influence of Dietary Vitamin A and Iron Deficiency on Hematologic Parameters and Body Weight of Young Male Wistar Rats

Micronutrient deficiency is one of the most prominent public health concerns; in particular, vitamin A and iron are determinants of appropriate development, and vitamin A influences iron homeostasis and metabolism. Here we compared the effects of diets that were sufficient and insufficient in vitamin A and iron on the hematologic parameters and body weight of rats. Male Wistar rats were randomly divided into 5 dietary groups (n = 7 per group): adequate in iron and vitamin A (control); adequate in iron but low in vitamin A (FesvAi); adequate in iron but lacking vitamin A (FesvAd); low in iron but adequate in vitamin A (FeivAs); and low in both iron and vitamin A (FeivAi). After 6 wk, rats showed significant differences in serum iron relative to the control diet (control, 256 ± 44 μg/dL; FesvAi, 220± 16 μg/dL; FesvAd, 181 ± 15 μg/dL; FeivAs, 131 ± 44 μg/dL; FeivAi, 75 ± 19 μg/dL). Rats on iron-deficient diets showed reduced Hgb values relative to the control diet (control, 15.9 ± 0.7 g/dL; FeivAs, 13.2 ± 1.6 g/dL; FeivAi, 12.9 ± 1.0 g/dL), MCV (control: 57 ± 10 fL; FeivAs, 48 ± 10 fL; FeivAi, 44 ± 3 fL), and Hct (control, 53% ± 2%; FeivAs, 44% ± 5%; FeivAi, 42% ± 8%). All of the experimental dietary groups showed significant differences in reticulocyte count when compared with the control group (control, 2.7% ± 2.2%; FesvAd, 0.6% ± 0.2%; FesvAi, 0.3% ± 0.1%; FeivAs, 1.2% ± 0.2%; FeivAi, 0.6% ± 0.5%). The mean difference in body weight for the experimental groups, relative to the control group, was 30 ± 10 g. These results suggested that, in young male Wistar rats, both iron and vitamin A are essential to cause increases in body weight and various hematologic parameters.

Short preheating at 41°C leads to a red blood cells count comparable to that in RET channel of Sysmex analysers in samples showing cold agglutination

AIMS

The presence of cold agglutinin in blood samples can cause a spontaneous agglutination of red blood cells (RBCs) when low temperature occurs. This phenomenon causes a spurious lowering of RBC count on the automated haematological analysers that are detected by incongruous values (≥370 g/L) of the mean cellular haemoglobi concentration (MCHC). A preheating at 37°C can remove the RBC agglutination generally resulting in a reliable count. It has been reported that the same result can be reached by using the optical reticulocyte (RET) channel of Sysmex analysers where the RBC count is not influenced by the presence of cold agglutinin. This study aims to evaluate these data in a larger population, with regard to environmental conditions on Sysmex analysers. We have also evaluated the influence of different thermal pretreatments on the RBC count.

METHODS

This study was performed on 96 remnants of peripheral blood samples (48 with MCHC in normal range and 48 with MCHC>370 g/L) which have been analysed in different preanalytical conditions on the Sysmex analysers.

RESULTS

A preheating of samples at 41°C for 1 min leads to a reversibility of the cold agglutination comparable to the one observed in the RET channel and yields better results compared with 37°C for 2 hours.

CONCLUSIONS

None of described procedures assure the complete cold agglutination reversibility in every case. Consequently, since the haematological analysers not yet provide reliable parameters to confirm the complete resolution of agglutination, further verification of RBC count accuracy needs to be performed.