The new hematology analyzer Sysmex XE-2100: performance evaluation of a novel white blood cell differential technology

Circulating Nucleated Red Blood Cells: An Updated Reference Interval

CONTEXT.—

Nucleated red blood cells (nRBCs) are not identified in the peripheral blood in healthy individuals beyond the neonatal period. Their presence in children and adults is traditionally considered pathologic. Contemporary hematology analyzers measure nRBCs at very low levels compared to traditional manual morphometric methods. The original launch of the Sysmex XN analyzer in this study's clinical laboratory verified the previously used nRBC reference interval of 0.00 to 0.01 × 106/μL. However, nRBC results from apparently healthy patients were flagged as abnormal (high), subsequently causing patient anxiety and increased subspecialty referrals.

OBJECTIVE.—

To determine whether current reference intervals (RIs) for nRBCs were clinically relevant.

DESIGN.—

We performed a prospective analysis of 405 300 specimens from nonhospitalized individuals who received a complete blood count. Applying inclusion/exclusion criteria produced a total specimen pool of 66 498.

RESULTS.—

Of the 66 498 samples with otherwise normal complete blood count results from healthy, nonhospitalized individuals, 338 showed results outside the previously established RI; 336 of 66 498 (0.5%) had nRBC results greater than 0.01 × 106/μL. Two samples had nRBC values greater than 0.10 ×106/μL.

CONCLUSIONS.—

Based on statistical analysis of our results, we concluded that the upper limit of the RI could be updated from 0.01 × 106/μL to 0.10 × 106/μL. Increasing the upper limit of normal for the nRBC RI should decrease patient consternation from an abnormal laboratory value and significantly decrease costs through reducing unnecessary follow-up care, and without causing patient harm.

The association of blood eosinophil counts and FEV1 decline: a cohort study

BACKGROUND

Accelerated lung function decline is characteristic of COPD. However, the association between blood eosinophil counts and lung function decline, accounting for current smoking status, in young individuals without prevalent lung disease is not fully understood.

METHODS

This is a cohort study of 629 784 Korean adults without COPD or a history of asthma at baseline who participated in health screening examinations including spirometry and differential white blood cell counts. We used a linear mixed-effects model to estimate the annual change in forced expiratory volume in 1 s (FEV1) (mL) by baseline blood eosinophil count, adjusting for covariates including smoking status. In addition, we performed a stratified analysis by baseline and time-varying smoking status.

RESULTS

During a mean follow-up of 6.5 years (maximum 17.8 years), the annual change in FEV1 (95% CI) in participants with eosinophil counts <100, 100-199, 200-299, 300-499 and ≥500 cells·µL-1 in the fully adjusted model were -23.3 (-23.9--22.7) mL, -24.3 (-24.9--23.7) mL, -24.8 (-25.5--24.2) mL, -25.5 (-26.2--24.8) mL and -26.8 (-27.7--25.9) mL, respectively. When stratified by smoking status, participants with higher eosinophil count had a faster decline in FEV1 than those with lower eosinophil count in both never- and ever-smokers, which persisted when time-varying smoking status was used.

CONCLUSIONS

Higher blood eosinophil counts were associated with a faster lung function decline among healthy individuals without lung disease, independent of smoking status. The findings suggest that higher blood eosinophil counts contribute to the risk of faster lung function decline, particularly among younger adults without a history of lung disease.

Prognostic significance of mean corpuscular volume in patients with pancreatic ductal adenocarcinoma and multimodal treatment

AIM OF THE STUDY

Mean corpuscular volume (MCV) has shown mounting evidence as a prognostic indicator in a number of malignancies. The aim of this study was to examine the prognostic potential of pretherapeutic MCV among patients with pancreatic ductal adenocarcinoma (PDAC) who underwent upfront resection or resection after neoadjuvant treatment (NT).

PATIENTS AND METHODS

Consecutive patients with PDAC who underwent pancreatic resection between 1997 and 2019 were included in this study. Neoadjuvantly treated patients' serum MCV was measured before NT and before surgery. In patients undergoing upfront resection serum MCV was measured before surgery. Median MCV values were used as cut-off to distinguish high from low MCV values.

RESULTS

Five hundred and forty-nine (438 upfront resected and 111 neoadjuvantly treated) patients were included in this study. Multivariate analysis revealed, that high MCV before and after NT, were independent negative prognostic factors for overall survival (P<0.01, respectively). Furthermore, the median MCV value from before to after NT increased significantly (P<0.001, Wilcoxon signed-rank test) and was (P=0.03, Wilcoxon rank sum test) associated with tumor response to NT.

CONCLUSION

High MCV is an independent adverse prognostic factor in patients with resectable neoadjuvantly treated PDAC and may qualify as useful indicator to help physicians to provide personalized prognostication.

Computer vision quantitation of erythrocyte shape abnormalities provides diagnostic, prognostic, and mechanistic insight

Examination of red blood cell (RBC) morphology in peripheral blood smears can help diagnose hematologic diseases, even in resource-limited settings, but this analysis remains subjective and semiquantitative with low throughput. Prior attempts to develop automated tools have been hampered by their poor reproducibility and limited clinical validation. Here, we present a novel, open-source machine-learning approach (denoted as RBC-diff) to quantify abnormal RBCs in peripheral smear images and generate an RBC morphology differential. RBC-diff cell counts showed high accuracy for single-cell classification (mean AUC, 0.93) and quantitation across smears (mean R2, 0.76 compared with experts, interexperts R2, 0.75). RBC-diff counts were concordant with the clinical morphology grading for 300 000+ images and recovered the expected pathophysiologic signals in diverse clinical cohorts. Criteria using RBC-diff counts distinguished thrombotic thrombocytopenic purpura and hemolytic uremic syndrome from other thrombotic microangiopathies, providing greater specificity than clinical morphology grading (72% vs 41%; P < .001) while maintaining high sensitivity (94% to 100%). Elevated RBC-diff schistocyte counts were associated with increased 6-month all-cause mortality in a cohort of 58 950 inpatients (9.5% mortality for schist. >1%, vs 4.7% for schist; <0.5%; P < .001) after controlling for comorbidities, demographics, clinical morphology grading, and blood count indices. RBC-diff also enabled the estimation of single-cell volume-morphology distributions, providing insight into the influence of morphology on routine blood count measures. Our codebase and expert-annotated images are included here to spur further advancement. These results illustrate that computer vision can enable rapid and accurate quantitation of RBC morphology, which may provide value in both clinical and research contexts.

Effect of liraglutide on atherosclerosis in patients with impaired glucose tolerance: A double‑blind, randomized controlled clinical trial

Glucagon-like peptide-1 receptor agonist liraglutide may have beneficial effects on atherosclerosis development in impaired glucose tolerance (IGT). To the best of our knowledge, however, little conclusive evidence from clinical trials has been presented. The present study aimed to investigate the effect of liraglutide on atherosclerosis progression in patients with IGT. The present study was a double-blind, randomized controlled clinical trial. A total of 39 of patients aged 20-75 years who were overweight or obese (BMI, 27-40 kg/m²) and presented IGT were randomized to receive liraglutide (n=17) or lifestyle interventions (n=22) for 6 months. Serum glucose and insulin (INS) levels, lipid profile, inflammatory biomarkers and carotid intima-media thickness (CIMT) were assessed at the start and end of each treatment. Side effects were also recorded. Liraglutide treatment was found to significantly improve glycaemia, including glycosylated hemoglobin, fasting and postprandial glucose as well as INS levels (all P<0.001). Liraglutide also significantly decreased serum total cholesterol and low-density lipoprotein levels (all P<0.001). Furthermore, serum levels of inflammatory biomarkers, as well as CIMT, were decreased following liraglutide treatment compared with those in the lifestyle intervention group (all P<0.001). Kaplan-Meier analysis showed that the risk of vasculopathy in the liraglutide group was lower than that in the lifestyle intervention group (log-rank test; P=0.041). The monitoring of drug-associated side effects indicated that the dose of liraglutide (0.6 to 1.2 mg/QD via subcutaneous injection) was safe and well-tolerated. The present study suggested that liraglutide may slow atherosclerosis development and improve inflammatory status as well as intimal function in patients with IGT with few side effects. The trial was registered through the Chinese Clinical Trial Registry (ChiCTR; trial registration no. ChiCTR2200063693; retrospectively registered) on Sep 14, 2022.

Ethyl glucuronide in hair detects a high rate of harmful alcohol consumption in presumed non-alcoholic fatty liver disease

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) and alcohol-related liver disease (ALD) cannot reliably be distinguished by routine diagnostics, and the role of alcohol consumption in metabolic dysfunction-associated fatty liver disease (MAFLD) remains unclear. We investigated alcohol consumption in patients with presumed NAFLD and ALD using novel objective alcohol markers.

METHODS

In total, 184 consecutive patients were included in this prospective observational study. Alcohol intake was assessed by ethylglucuronide in hair (hEtG) and urine (uEtG); the utility of these measures for alcohol detection was compared to Alcohol Use Disorders Identification Test-Consumption (AUDIT-C), carbohydrate deficient transferrin (CDT), mean corpuscular volume (MCV), gamma-glutamyltransferase (GGT), and ALD/NAFLD index (ANI). Clinical characteristics of patients with NAFLD and ALD were re-assessed after reclassification based on repeated moderate (≥10 g <60 g EtOH/day) and excessive (≥60 g EtOH/day) alcohol consumption, and patients were retrospectively reclassified based on MAFLD criteria.

RESULTS

Repeated moderate to excessive alcohol consumption was detected in 28.6%, 28.5%, and 25.0% of patients with presumed NAFLD, ALD or MAFLD, respectively. ANI score, AUDIT-C, uEtG, and hEtG showed AUCs of 0.628, 0.733, 0.754, and 0.927 for the detection of repeated moderate to excessive alcohol consumption, respectively. The indirect markers CDT, MCV and GGT were not reliable. Patients with repeated moderate or excessive alcohol consumption were significantly more often male, had a significantly lower BMI, and suffered significantly less often from type 2 diabetes or impaired glucose tolerance.

CONCLUSIONS

In total, 28.6% of patients with presumed NAFLD, and 25.0% with MAFLD are at risk of alcohol-related liver damage. AUDIT-C, uEtG and hEtG should be used to screen for alcohol consumption in patients with fatty liver disease.

LAY SUMMARY

Fatty liver disease can be caused by metabolic factors and/or alcohol consumption. The diagnosis of non-alcoholic fatty liver disease (NAFLD) is based on the exclusion of harmful alcohol consumption, while metabolic dysfunction-associated fatty liver disease (MAFLD), which has been proposed as a new name for NAFLD, is based on the presence of metabolic comorbidities and allows for alcohol consumption. Herein, we show that up to 29% of patients diagnosed with NAFLD and 25% with MAFLD are at risk of alcohol-related liver damage. We show that ethyl glucuronide (a metabolite of alcohol) in the hair and urine can accurately detect potentially harmful alcohol consumption in these patients - as such, these tests should be integrated into routine diagnostic work-up for patients with fatty liver disease.

A low-cost flow cell for flow cytometry

Flow cytometry is an essential analytical technique used in biomedical diagnostics to measure properties of cells, micro-organisms, and particles. Laser light is scattered from particles focused in a flow cell and collected by light sensors, where the intensity of the scattered light is a function of the scattering angle, the refractive index of the particle and surrounding medium, the wavelength of light, and the size and the shape of the particle. One of the critical parts of the cytometer is the flow cell where the particle stream is constrained into a tight region within 10-30 μm using hydrodynamic focusing. The conventional flow cells use thick quartz flow cells, which are expensive and therefore not suitable for instruments targeted for resource-constrained settings. We demonstrate a compact, economical, bio-compatible flow cell assembly design that incorporates inexpensive and easily available capillaries attached to sturdy polymer fixtures in a simple manner that performs the focusing of a sample stream of particles. The flow cell has been tested by studying the relation between sample core diameter, and sample and sheath flow rates. Small-angle scattering (forward scatter) and wide-angle scattering (side scatter) have been captured for the enumeration and characterization of particles. We show excellent agreement between the size distribution obtained via direct imaging and that obtained from light scattering. The flow cell was also used to successfully size white blood cells in human blood samples.

An Evaluation of Nuclei Preparation of the Dormant Axillary Bud of Grapevine for Cell Cycle Analysis by Flow Cytometry

Whether the division of cells of a dormant meristem may be arrested, e.g., in the G1 phase, has proven to be an extremely difficult hypothesis to test. This is particularly so for woody perennial buds, where dormant and quiescent states are diffuse, and the organ may remain visibly unchanged for 6-9 months of the year. Flow cytometry (FCM) has been widely applied in plant studies to determine the genome size and endopolyploidy. In this study, we present the application of FCM to measure the cell cycle status in mature dormant buds of grapevine (Vitis vinifera cv. Cabernet Sauvignon), which represent a technically recalcitrant structure. This protocol illustrates the optimisation and validation of FCM data analysis to calculate the cell cycle status, or mitotic index, of dormant grapevine buds. We have shown how contamination with debris can be experimentally managed and give reference to the more malleable tomato leaves. We have also given a clear illustration of the primary pitfalls of data analysis to avoid artefacts or false results. Data acquisition and analysis strategies are detailed and can be readily applied to analyse FCM data from other recalcitrant plant samples.

NEUT-SFL in Patients with COVID-ARDS: A Novel Biomarker for Thrombotic Events?

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped RNA virus first identified in December 2019 in Wuhan, China, and responsible for coronavirus disease 2019 (COVID-19). The ongoing COVID-19 pandemic is impacting healthcare worldwide. Patients who develop coagulopathy have worse outcomes. The pathophysiology of COVID-19 suggests a strong interplay between hemostasis and immune cells, especially neutrophils. Our purpose was to assess neutrophil fluorescence as a potential biomarker of deep vein thrombosis (DVT) in patients with COVID-acute respiratory distress syndrome (COVID-ARDS). Sixty-one patients with COVID-ARDS admitted to the four intensive care units (ICUs) of a French general hospital were included in this prospective study. Neutrophil activation was assessed by measuring neutrophil fluorescence (NEUT-Side Fluorescence Light, NEUT-SFL) with a specific fluorescent dye staining analyzed by a routine automated flow cytometer Sysmex XN-3000™ (Sysmex, Kobe, Japan). DVT was diagnosed by complete duplex ultrasound (CDU). We found that NEUT-SFL was elevated on admission in patients with COVID-ARDS (49.76 AU, reference value 46.40 AU, p < 0.001), but did not differ between patients with DVT (49.99 AU) and those without (49.52 AU, p = 0.555). NEUT-SFL is elevated in patients with COVID-ARDS, reflecting neutrophil activation, but cannot be used as a marker of thrombosis. Because neutrophils are at interface between immune response and hemostasis through release of neutrophil extracellular traps, monitoring their activation could be an interesting approach to improve our management of coagulopathy during COVID-ARDS. Further research is needed to better understand the pathophysiology of COVID-19 and identify high-performance biomarkers.

Blood eosinophil counts and the development of obstructive lung disease: the Kangbuk Samsung Health Study

The impact of blood eosinophil counts on the development of chronic obstructive lung disease (COPD) is unknown. We investigated whether a higher blood eosinophil counts was associated with the risk of developing obstructive lung disease (OLD) in a large cohort of men and women free lung disease at baseline.Cohort study of 359 456 Korean adults without a history of asthma and without OLD at baseline who participated in health screening exams including spirometry. OLD was defined as pre-bronchodilator FEV₁/FVC<0.7 and FEV₁<80% predicted.After a median follow-up of 5.6 years (interquartile range, 2.9-9.2), 5008 participants developed incident OLD (incidence rate, 2.1 per 1000 person-years; 95% CI, 2.1-2.2). In the fully-adjusted model, the HR (95% CI) for incident OLD comparing eosinophil counts of 100-<200, 200-<300, 300-<500 and ≥500 cells·μL^-1 to <100 cells·μL^-1 were 1.07 (1.00-1.15), 1.30 (1.20-1.42), 1.46 (1.33-1.60) and 1.72 (1.51-1.95) (p for trend <0.001). These associations were consistent in clinically relevant subgroups, including never, former, and current smokers.In this large longitudinal cohort study, blood eosinophil counts were positively associated with the risk of developing of OLD. Our findings indicate a potential role of eosinophil count as an independent risk factor for developing COPD.

Pseudothrombocytopenia Inducing Nonindicated Platelet Transfusion after Cardiac Surgery

Pseudothrombocytopenia (PTCP) is an in vitro phenomenon of low platelet count caused by the agglutination of platelets, leading to false low platelet counts in automated cell counting. Typically, ethylenediaminetetraacetic acid (EDTA) mediates this platelet clumping. PTCP has little clinical significance, but misdiagnosis may lead to unnecessary diagnostic tests and treatment. In this case report, we present a 65-year-old Caucasian female suffering from multiple complications during and after cardiac surgery. During her postoperative stay at the ICU, she was diagnosed with thrombocytopenia and an inadequate response to platelet supplementation.

Basophil counting in hematology analyzers: time to discontinue?

Basophils (basophilic granulocytes) are the least abundant cells in blood. Nowadays, basophils are included in the complete blood count performed by hematology analyzers and therefore reported in practically all patients in whom hematologic investigations are requested. However, hematology analyzers are not reliable enough to report clinically useful results. This is due to a combination of very high analytical imprecision and poor specificity, because the chemical and physical methods used for basophil counting in hematology analyzers are ill-defined and thus basophils are not well recognized by the analyzers. As a result, false basophil counts are quite common. In view of increasing analytical performance demands, hematology laboratories should stop reporting basophil counts produced by hematology analyzers. Suggestions for alternative pathways are presented for those situations where basophils are of clinical relevance.

White blood cell counting at point-of-care testing: A review

White blood cells, which are also called leukocytes, are found in the immune system that are involved in protecting the body against infections and foreign invaders. Conventional methods of leukocyte analysis provide valuable and accurate information to medical specialists. Analyzing and diagnosing of a disease requires a combination of multiple biomarkers, in some cases, however, such as personal health care, this will occupy some medical resources and causes unnecessary consumption. Traditional method (such as flow cytometer) for WBC counting is time and labor consuming. Compared to gold standard (flow-based fraction/micropore filtration) or improved filtration methods for WBC counting, this is still a lengthy and time consuming process and can lead to membrane fouling due to the rapid accumulation of biological materials. Therefore, the analysis of WBC counts requires more compact and efficient equipment. The microfluidic technologies, powered by different field (force, thermal, acoustic, optical, magnetic) and other methods for leukocyte counting and analysis, are much cost-efficient and can be used in in-home or in resource-limited areas to achieve Point-of-Care (POC). In this review, we highlight the mainstream devices that have been commercialized and extensively employed for patients for WBC counting, Next, we present some recent development with regards to leucocyte counting (mainly microfluidic technologies) and comment on their relative merits. We aim to focus and discuss the possibility of achieving POC and help researchers to tackle individual challenges accordingly. Finally, we offer some technologies in addition to previous detection devices, such as image recognition technology and cloud computing, which we believe have great potential to further promote real-time detection and improve medical diagnosis.

Defibrotide enhances fibrinolysis in human endotoxemia - a randomized, double blind, crossover trial in healthy volunteers

Defibrotide is approved for the treatment of sinusoidal obstruction syndrome after allogeneic stem cell transplantation. The exact mode of action of defibrotide is unclear and human in vivo data are scarce. In this randomized, double blind, crossover trial we included 20 healthy volunteers. Four were randomized to receive placebo, while 16 received a 2 ng/kg bodyweight bolus of lipopolysaccharide (LPS). Infusion of 6.25 mg/kg defibrotide or placebo was started one hour before the injection of the LPS bolus. Plasma levels of prothrombin fragments F1 + 2, thrombin-antithrombin complexes, von Willebrand factor, E-selectin, tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor-1 (PAI-1), plasmin-antiplasmin complexes (PAP), tumor necrosis factor-α, interleukin 6, and C-reactive protein were measured. Thromboelastometry was performed. Infusion of defibrotide did not reduce the LPS-induced activation of coagulation, the endothelium or the release of pro-inflammatory cytokines. However, defibrotide increased t-PA antigen levels by 31% (Quartiles: 2–49%, p = 0.026) and PAP concentrations by 13% (−4–41%, p = 0.039), while PAI-1 levels remained unaffected. Moreover, defibrotide reduced C-reactive protein levels by 13% (0–17%, p = 0.002). A transient increase in the clotting time in thromboelastometry and a decrease in F1 + 2 prothrombin fragments suggests modest anticoagulant properties. In conclusion, defibrotide infusion enhanced fibrinolysis and reduced C-reactive protein levels during experimental endotoxemia.

Cutoff Value for Correcting White Blood Cell Count for Nucleated Red Blood Cells: What is it? Why is it Important?

Nucleated red blood cells (RBCs) are normally observed in the peripheral blood of neonates and during pregnancy. Under other conditions, the presence of nucleated RBCs in circulating blood indicates disorder in the blood-producing mechanism. The increased presence of nucleated RBCs, however, falsely elevates the leukocyte count, as measured by most automated hematology analyzers, warranting a manual correction of the leukocyte count. For a long time, cutoff values for correcting white blood cell (WBC) count for the presence of nucleated RBCs have been used regularly, particularly in developing countries. However, because those values are largely subjective, they can vary widely between laboratories worldwide. These varied cutoff values include 1, 5, 10, 20, and 50; it appears that the numbers 5 and 10 are the most common values used in corrections; the reasons require further elucidation. In this article, we discuss the merits of correcting the WBC count for nucleated RBCs at certain cutoff points.

High Mean Corpuscular Volume Predicts Poor Outcome for Patients With Gastroesophageal Adenocarcinoma

BACKGROUND

Elevated mean corpuscular volume (MCV) is associated with a diminished prognosis for various tumor entities. This study aimed to evaluate the association between preoperative serum MCV levels and both overall (OS) and disease-free survival (DFS) for patients with resectable adenocarcinomas of the esophagogastric junction (AEG).

METHODS

This study included consecutive patients undergoing surgical resection between 1992 and 2016. Measured preoperative MCV levels were stratified into quintiles and correlated with patients' survival and clinicopathologic characteristics.

RESULTS

The study analyzed 314 patients with a median OS of 36.8 months and a median DFS of 20.6 months. The multivariate analysis showed that preoperatively elevated MCV is a significant prognostic factor for OS (hazard ratio [HR], 1.05; 95% confidence interval [CI], 1.03-1.08; P < 0.001) and DFS (HR, 1.05; 95% CI, 1.03-1.08; P < 0.001). In the subgroup analysis of neoadjuvantly treated and untreated patients, MCV remained an independent prognostic factor for OS (HR, 1.08; 95% CI, 1.04-1.12; P < 0.001) and DFS (HR, 1.07; 95% CI, 1.03-1.12; P < 0.001) in both groups. In the univariate analysis, tumor stage and differentiation, adjuvant chemotherapy, MCV, mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were significantly correlated with diminished OS and DFS.

CONCLUSION

Preoperatively elevated MCV is an independent prognostic factor for patients with adenocarcinomas of the esophagus and the gastroesophageal junction.

Added value of the DIC score and of D-dimer to predict outcome after successfully resuscitated out-of-hospital cardiac arrest

BACKGROUND

Recent Korean data suggest a high prevalence of overt disseminated intravascular coagulation (DIC) and a good predictive performance of the ISTH DIC score in successfully resuscitated out-of-hospital cardiac arrest.

OBJECTIVES

We hypothesised that in a European cohort of resuscitated out-of-hospital cardiac arrest patients the prevalence of DIC is substantially lower. Furthermore, the determination of D-dimer levels at admission, but not the DIC score, could improve mortality prediction above traditional predictors.

PATIENTS/METHODS

Data were extracted from a prospective cardiac arrest registry including patients admitted between 2006 and 2015, who achieved return of spontaneous circulation and had parameters for DIC score calculation available. The primary outcome was the prevalence of overt DIC at admission. Secondary outcomes included the association of overt DIC with 30-day mortality and the contribution of the DIC score and D-dimer levels to 30-day mortality prediction using logistic regression. Three stepwise models were evaluated by receiver-operating-characteristic analysis.

RESULTS

Out of 1179 patients 388 were included in the study. Overt DIC was present in 8% of patients and associated with substantial 30-day mortality (83% vs. 39%). The AUC for model 1, including traditional mortality predictors, was 0.83. The inclusion of D-dimer levels significantly improved prognostication above traditional predictors (model 3, AUC 0.89), whereas the inclusion of the DIC Score had no effect on mortality prediction (model 2, AUC 0.83).

CONCLUSION

Overt DIC was rare in a European cohort of out-of-hospital cardiac arrest patients. D-dimer levels improved 30-day mortality prediction and provided added value to assess early mortality risk after successful resuscitation.

Detection of activated neutrophils by reactive oxygen species production using a hematology analyzer

Neutrophils are recruited to infection sites and kill bacteria by phagocytosis and reactive oxygen species (ROS) production. It has been reported that vacuoles are present in neutrophils that produce ROS and are present in large numbers in blood smears of patients with bacterial infections. The leukocyte differentiation function on the Sysmex automated hematology analyzer classifies leukocytes by flow cytometry. Particularly, side-scattered light is known to reflect the quantity of organelles. This study investigated the possibility of detecting vacuoles or invagination of cell membrane in neutrophils producing ROS using a hematology analyzer. Whole blood and polymorphonuclear (PMN) cell fractions were activated with phorbol myristate acetate (PMA) or formylmethionylleucylphenylalanine (fMLP) and analyzed using the Sysmex XE-2100 automated hematology analyzer. PMN fractions were morphologically analyzed with a confocal laser scanning microscope (CLSM), electron microscope (EM), and general-purpose conventional flow cytometer. In the white blood cell differentiation scattergram obtained in this analysis, a new cluster separate from the original neutrophil cluster appeared in the eosinophil area in an area of higher side-scattering (SSC) intensity. Flow cytometry analysis of the PMN fractions revealed that the cells in this new cluster were CD16b- and APF-positive, indicating that the cells were activated neutrophils that produced ROS. CLSM and EM findings revealed that ROS production occurred in the cytoplasm and that the activated neutrophils contained some vacuole-like structures of vacuoles or invagination of cell membrane. Vacuole-like Sstructures were found within the cytoplasm of neutrophils producing ROS. These neutrophils were detected as an independent cluster in the eosinophil area with higher SSC intensity than that shown by neutrophils in the traditional cluster on the white blood cell differentiation scattergram, likely because the vacuole-like structures increased the SSC intensity.

Useful information provided by graphic displays of automated cell counter in hematological malignancies

BACKGROUND

Automated cell counters have become more and more sophisticated with passing years. The numerical and graphic data both provide useful clues for suspecting a diagnosis especially when the workload is very high.

AIM

We present our experience of useful information provided by graphic displays of an automated cell counter in hematological malignancies in a cancer hospital where a large number of complete blood count (CBC) requests are received either before or during chemotherapy. This study was conducted to assess the usefulness of hematology cell counter, viz. WBC-Diff (WBC differential), WBC/BASO (WBC basophil) and IMI (immature myeloid information) channel scatter plots, and the flaggings generated in various hematological malignancies.

MATERIAL & METHODS

The graphic displays have been compiled over a period of 1 year (October 2015-September 2016) from blood samples of various solid and hematological malignancies (approximately 400 per day) received for routine CBC in the laboratory. Approximately 50 000 scattergrams have been analyzed during the study period. The findings were confirmed by peripheral blood smear examination.

RESULTS

The scattergram analysis on XE-2100 is very sensitive as well as specific for diagnosing acute leukemia, viz. acute myeloid leukemia, acute lymphoblastic leukemia; chronic myeloproliferative disorders, viz. chronic myeloid leukemia; and chronic lymphoproliferative disorder especially chronic lymphocytic leukemia.

CONCLUSION

It is suggested that the laboratories using the hematology analyzers be aware of graphic display patterns in addition to flaggings generated which provide additional information and give clue toward the diagnosis even before peripheral smear examination.

Colistin dampens fibrinolysis and endothelial activation during endotoxaemia. A randomised, double blind trial

Colistin electrostatically interacts with lipopolysaccharides (LPS). Preclinical studies demonstrated beneficial effects of colistin on LPS-induced coagulation and fibrinolysis. The objective of this trial was to investigate the effects of colistin during experimental endotoxaemia. In this randomised, double-blind, placebo-controlled, crossover trial 16 healthy volunteers received a 2 ng/kg LPS bolus after infusion of 2.5 million IU colistin or placebo. Plasma levels of F1+2 prothrombin fragments, thrombin-antithrombin complexes (TAT), von Willebrand factor antigen levels (vWF), E-selectin, plasmin-antiplasmin complexes (PAP), tissue-type plasminogen activator (t-PA) antigen and activity, plasminogen activator inhibitor-1 (PAI-1) were measured. Infusion of colistin significantly reduced peak concentrations of PAP complexes by 70 %, t-PA antigen levels by 63 % and t-PA activity by 48 %, while PAI-1 levels decreased numerically by 63 %. Two hours after the LPS bolus F1+2 levels and TAT complexes were slightly reduced in the colistin period, but peak concentrations were similar in both periods. Colistin blunted the LPS induced four-fold increase in soluble E-Selectin levels by ∼50 % and the two-fold increase in vWF antigen levels by ∼70 %. The LPS-scavenging actions of colistin significantly reduce endothelial activation and fibrinolytic response in the human endotoxaemia model, while the activation of the coagulation system remains largely unaffected.

Note: This work was conducted at the Medical University of Vienna.

EudraCT-Nr.: 2014–00285720

Supplementary Material to this article is available online at http://www.thrombosis-online.com

Evaluation of criteria of manual blood smear review following automated complete blood counts in a large university hospital

Background

There is great interest in reducing the number of automated complete blood counts requiring manual blood smear reviews without sacrificing the quality of patient care. This study was aimed at evaluating and establishing appropriate screening criteria for manual blood smear reviews to improve the performance in a hematology laboratory.

Method

A total of 1977 consecutive samples from the daily workload were used to evaluate four sets of screening criteria for manual blood smear reviews to identify samples with positive smear findings. Three sets of screening criteria were arbitrarily proposed in this study: Group 1 (narrow ranges), Group 2 (intermediate ranges), and Group 3 (wide limits) and one set (Group 4) was adapted from the International Society for Laboratory Hematology. All samples were run on Sysmex hematology analyzers and were investigated using manual blood smear reviews. Diagnostic accuracy and agreement were performed for each set of screening criteria, including an investigation of microscopic review rate and efficiency.

Results

The microscopic review rates for Groups 1, 2, 3 and 4 were 73.85%, 54.52%, 46.33% and 46.38%, respectively; the false-negative rates were 0.50%, 1.97%, 2.73% and 3.95%, respectively. The efficiency and negative predictive values of Group 3 were 73.04% and 4.91%, respectively.

Conclusions

Group 3 had the best relationship between safety (false-negative rate: ≤3%) and efficiency to estimate the limits of automation in performing complete blood counts. This study strengthens the importance of establishing screening criteria for manual blood smear reviews, which account for the different contexts in which hematological determinations are performed. Each laboratory should optimize the screening criteria for manual blood smear reviews in order to maximize their efficiency and safety.

Immature platelet fraction in septic patients: clinical relevance of immature platelet fraction is limited to the sensitive and accurate discrimination of septic patients from non-septic patients, not to the discrimination of sepsis severity

Background

The immature platelet fraction (IPF) reflects the degree of reticulated platelets. We evaluated performances of IPF as a biomarker for the discrimination of septic patients from non-septic patients and sepsis severity.

Methods

Total 312 patients admitted between March and July 2013 were enrolled and samples were obtained at admission. Lactate (LA), procalcitonin (PCT), C-reactive protein (CRP), immature granulocyte fraction (IG), immature reticulocyte fraction (IRF), and IPF were analyzed as sepsis biomarkers and their performances were compared.

Results

The performance of IPF (area under the curve [AUC]=0.868) in the discrimination of septic patients from non-septic patients was comparable to PCT/CRP/LA/IG (AUC=0.923/0.940/0.781/0.812, P=0.233/0.106/0.186/0.353, respectively), and was significantly better than the IRF (AUC=0.658, P=0.007). Sensitivity (89.8%, 95% confidence interval [CI] 84.9-99.8%) and accuracy (83.2%, 95% CI 78.8-90.0%) of IPF were the best among all biomarkers. The performance of IPF in discriminating septic patients from non-septic patients with local infection showed similar results. However, the IPF could not efficiently discriminate sepsis severity (AUC=0.599), similar to other biomarkers (AUC=0.519-0.752).

Conclusions

The IPF possessed high sensitivity/accuracy in discriminating septic patients from non-septic patients, regardless of local infection status. However, the IPF did not efficiently discriminate sepsis severity. The clinical relevance of IPF as a sepsis biomarker is, therefore, limited to sensitive and accurate discrimination of septic patients from non-septic patients, not discrimination of sepsis severity.

Impact of Integrating Rumke Statistics to Assist with Choosing Between Automated Hematology Analyzer Differentials vs Manual Differentials

BACKGROUND

To optimize precision of nucleated blood cell counting, the clinical laboratory scientist should post the automated differential rather than the manual differential if the former is within the 95% CI of the latter, as determined by the "Rumke statistic." The objective of this study was to determine the potential impact of real-time, computer-assisted use of Rumke statistics for more judicious use of the automated vs digitally imaged, manual differential.

METHODS

Complete blood counts with automated differentials produced by a XE5000™ hematology analyzer (Sysmex) were compared with both the DM96 (CellaVision™ AB) preclassification differentials and the posted reclassified manual differentials, using the Rumke 95% CIs as calculated using the Clopper-Pearson method.

RESULTS

A total of 44.7% of manual differentials had no statistical or clinical justification over the automated differential. In addition, 31.1% of manual differentials had statistical discrepancies between the instrument absolute neutrophil count (IANC) and manual absolute neutrophil count (ANC). Nineteen of these IANC/manual ANC discrepant samples had ANCs below 1500/μL, a decision level for cancer treatment. Holding the IANC when it is less than 2000/μL until after manual smear review would have prevented the posting of any IANC vs manual ANC discrepant results at the 1500/μL ANC decision threshold.

CONCLUSIONS

A real-time operator alert concerning the statistical identity of imaging device differentials vs automated differentials could have reduced manual differentials by nearly 45%. Not posting unnecessary manual differentials for the cases with IANC/manual ANC discrepancies would have likely reduced clinical error/confusion.

Performance of the XN-2000 WPC channel-flagging to differentiate reactive and neoplastic leukocytosis

BACKGROUND

The distinction between reactive and neoplastic leukocytes, especially atypical lymphocytes suspected to be reactive or neoplastic, is a particular challenge in automated hematological cell differentiation. The aim of the study was to evaluate the performance of the XN analyzer supplemented with the WPC channel for differentiating between reactive and neoplastic leukocytosis.

METHODS

Blood samples of 253 patients with viral infections, lymphoma or leukemia were analyzed by the Sysmex XN-2000 analyzer equipped with the WPC channel. The results were compared to routine leukocyte differentiation using the routine Sysmex XE-2100 analyzer and automated digital microscopy (DM96). The combined information from standard morphology, immune phenotyping and clinical diagnosis served as a reference.

RESULTS

The XN WPC channel demonstrated an excellent performance for differentiating neoplastic (AUC=0.933) and reactive leukocytosis (AUC=0.900) as compared to morphological smear examination (AUC=0.949 and AUC=0.968, respectively) or to the differentiation results of our routine hematology analyzer (AUC=0.630 and AUC=0.635, respectively).

CONCLUSIONS

Our data show that the combined WDF/WPC of the Sysmex XN-Series analyzer is advantageous in the automated differentiation of neoplastic and reactive leukocytosis, thus supporting the correct diagnostic decision in the daily laboratory routine.

Immature/total granulocyte ratio improves early prediction of neurological outcome after out-of-hospital cardiac arrest: the MyeloScore study

Background

Elevation of the immature/total granulocyte (I/T-G) ratio has been reported after out-of-hospital cardiac arrest (OHCA). Our purpose here was to evaluate the prognostic significance of the I/T-G ratio and to investigate whether the I/T-G ratio improves neurological outcome prediction after OHCA.

Methods

This single-center prospective cohort study included consecutive immunocompetent patients admitted to our intensive care unit over a 3-year period (2012–2014) after successfully resuscitated OHCA. The I/T-G ratio was determined in blood samples collected at admission.

Results

We studied 204 patients (77 % male, median age, 58 [48–67] years), of whom 64 % had a suspected cardiac cause of OHCA, 62 % died in the unit, and 31.5 % survived with good cerebral function. Independent outcome predictors by multivariate analysis were age, first shockable rhythm, bystander-initiated resuscitation, and I/T-G ratio. Compared to the model computed without the I/T-G ratio, the model with the ratio performed significantly better [areas under the ROC curves (AUCs), 0.78 vs. 0.83, respectively; P = 0.04]. These items were used to develop the MyeloScore equation: ([0.47 × I/T-G ratio] + [0.023 × age in years]) − 1.26 if initial VF/VT − 1.1 if bystander-initiated CPR. The MyeloScore predicted neurological outcomes with similar accuracy to the previously reported OHCA score (0.83 and 0.85, respectively; P = 0.6). The ROC–AUC was 0.84, providing external validation of the MyeloScore.

Conclusions

The I/T-G ratio independently predicts neurological outcome after OHCA and, when added to other known risk factors, improves neurological outcome prediction. The clinical performance of the MyeloScore requires evaluation in a prospective study.

Local verification between the hematological analyzers Sysmex XN-series and XE-5000

INTRODUCTION

The aim of this study was to perform a verification of the hematology analyzer Sysmex XN-2000 by comparing with the previous XE-5000. This study assessed the precision and carryover on the XN-2000 and the systematic error between the both counters according to desirable biological variability criterion and a flag comparison study.

METHODS

Within-run precision and between-batch precision were measured according to the ICSH guidelines. A comparative study was performed analyzing two hundred and six samples of peripheral blood from patients. The statistical study was conducted using the Passing-Bablok and Bland-Altman analyses. The leucocyte flag comparison was made by measuring the efficiency rate.

RESULTS

Between-batch precision was lower than that recommended by the biological variability criterion and manufacturer specifications. The comparison gave nonagreement results for neutrophil and basophil counts according to the criterion of biological variability. Erythroblasts and immature granulocytes showed nonagreement, but there is no available biological variation database for these parameters to compare with. Nevertheless, excellent absolute agreement was found for red blood cell parameters, and for platelet, lymphocyte, monocyte, and eosinophil counts.

CONCLUSIONS

The global results obtained for the precision, comparability, and efficiency provide a satisfactory integration of the XN-2000 in the core laboratory routine and accomplish an optimal reliability.

Automated Nucleated RBC Measurement Using the Sysmex XE-5000 Hematology Analyzer: Frequency and Clinical Significance of the Nucleated RBCs

OBJECTIVES

We validated the automatic nucleated RBC (nRBC) count on a Sysmex XE-5000 hematology analyzer (Sysmex Corporation, Kobe, Japan) and then evaluated the frequency of nRBCs in our patient population.

METHODS

We correlated automated nRBC enumeration by the Sysmex XE-5000 hematology analyzer on 463 peripheral blood (PB) samples with the manual nRBC count. Results from 360,504 consecutive blood samples were reviewed to determine the frequency of nRBCs in various patient populations in our hospital.

RESULTS

There was a strong correlation between the automated and manual nRBC count (Pearson's r = 0.97). Frequency of nRBCs varied in different patient populations and was significantly higher in the presence of other morphology flags or abnormal CBC parameters. Low-level nRBCs (0.2%-1.3%) were detected in 0.5% of samples with otherwise normal parameters.

CONCLUSIONS

The automated method offers many advantages for high-throughput laboratories, including faster turnaround time, labor savings, and high reliability. Automated nRBC measurement allowed us to recognize a group of individuals who have low-level circulating nRBCs with otherwise normal CBC parameters. Nucleated RBC levels below 1.5% as detected by the automated count may be present in patients without increased erythropoiesis or a pathologic bone marrow process.

Performance evaluation of the Sysmex XN-1000 hematology analyzer in assessment of the white blood cell count differential in pediatric specimens

INTRODUCTION

The automated XN-1000 hematology analyzer enables to perform a blood cell count and a leukocyte differential. When abnormal cells were detected, a flag was generated by the analyzer and a manual microscopic examination of the corresponding blood film was performed.

METHODS

We compared the white blood cell differentials provided by the automated hematology analyzer XN-1000 in a pediatric population (n = 765) with those obtained through microscopic examination by cytologists and those obtained using a previous version of this analyzer, the XE-2100. Leukocytes count as well as flags sensitivity and specificity was analyzed.

RESULTS

The leukocytes count provided by the analyzer is in good accordance with the differential obtained by manual count in children older than 3 months. The sensitivity for blast detection is 99% and the detection of reactive cells is 63%. The flag specificity remains low (<35%) for blood samples collected from infants between 8 days and 2 years of age, but increases up to 67% thereafter. The results obtained with the XN-1000 analyzer show an improvement in comparison with those obtained with the XE-2100 analyzer.

CONCLUSION

The automated WBC differential provided by the XN-1000 analyzer in the pediatric setting is accurate, but a meticulous microscopic examination of blood smears remains necessary for infants up to 3 months of age to validate the analyzer flags.

MMP-8 genotypes influence the inflammatory response in human endotoxemia

Clinical studies have reported associations between MMP-8 genotypes and clinical outcomes without exploring underlying mechanisms. This study aims to understand the influence of the rs1940475 SNP on downstream chemokine and cytokine response in human endotoxemia. Rs1940475 was genotyped in 44 healthy Caucasian males, who were challenged with an intravenous bolus of 2 ng/kg lipopolysaccharide (LPS). Plasma levels of tumor necrosis factor (TNF), interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-1α were measured at baseline and 2, 4, 6, and 24 h after LPS infusion with high-sensitivity enzyme immunoassays. Peak TNF levels at 2 h after LPS infusion were significantly higher in subjects with AA genotype compared to subjects with AG or GG genotypes (185 pg/mL [IQR, 154–234] vs. 94 pg/mL [IQR, 65–125] vs. 107 pg/mL [IQR, 80–241], respectively; p = 0.03 between groups). Peak IL-6 levels were trend-wise higher in subjects with AA genotype compared to those with AG or GG genotypes (566 pg/mL [IQR, 294–644] vs. 278 pg/mL [IQR, 184–539] and 329 pg/mL [IQR, 240–492], respectively; p = 0.15 between groups). In contrast, peak MIP-1α at 2 h was highest in GG genotype carriers compared to those with AG or AA genotypes (602 pg/mL [IQR, 449–727] vs. 389 pg/mL [IQR, 375–490] and 510 pg/mL [425–813], respectively; p < 0.03 between groups). AA genotype carriers had highest peak TNF and IL-6 levels after LPS challenge, whereas peak MIP-1α levels were highest in GG carriers. This indicates that the rs1940475 SNP modifies the host response to inflammatory stimuli, which may in part explain previously shown associations with clinical outcomes.

Therapeutic hypothermia delays the C-reactive protein response and suppresses white blood cell and platelet count in infants with neonatal encephalopathy

BACKGROUND

Therapeutic hypothermia (HT) delays the cytokine response in infants with neonatal encephalopathy (NE).

OBJECTIVE

To determine if HT delayed the C-reactive protein (CRP) response and altered white blood cell (WBC), neutrophil and platelet count course during the first week of life in infants with NE.

DESIGN

Retrospective cohort study.

SETTING

Regional neonatal intensive care unit, UK.

PATIENTS

104 term infants with NE (38 normothermia (NT) and 66 HT) born between 1998 and 2010. Infants not exposed to prenatal sepsis risk factors were classified as group 'A' and exposed infants to group 'B'. CRP >10 mg/L was defined as significant response.

MAIN OUTCOME MEASURES

Time to CRP >10 mg/L, peak CRP, WBC, neutrophil and platelet count.

RESULTS

Blood cultures were negative in all the infants. In babies who had CRP response, HT delayed time to CRP >10 mg/L (median (95% CI): group A, HT: 36 h (28.3 to 48.0); NT: 24 h (0.0 to 24.0); p=0.001; group B, HT: 30 h (15.2 to 56.8); NT: 12 h (0.0 to 24.0); p=0.009) and time to peak CRP (median (95% CI): group A, HT: 60 h (60.0 to 72.0); NT: 36 h (0.0 to 48.0); p=0.001; group B, HT: 84 h (62.1 to 120.0); NT: 24 h (0.0 to 36.0); p=0.001). Compared with NT, HT was associated with reduction in slope of CRP elevation by 0.5 (95% CI 0.04 to 0.97), WBC by 2.18×10(9)/L (95% CI 0.002 to 4.35) and platelet count by 32.3×10(9)/L (95% CI 2.75 to 61.8) independent of exposure to sepsis risk, meconium aspiration and severity of asphyxia.

CONCLUSIONS

Therapeutic hypothermia delayed the initiation of CRP and its peak response, and depressed the WBC and platelet count compared with NT.

Fraction of immature granulocytes reflects severity but not mortality in sepsis

OBJECTIVE

In order to validate immature granulocytes as a universal biomarker, we have compared the clinical relevance of the proportion of immature granulocytes (IG%), measured using Sysmex XE-2100, with other biomarkers (white blood cell, C-reactive protein, lactate and procalcitonin).

METHODS

This single center, retrospective study included 184 patients with sepsis admitted to an emergency department. Patients were classified into two groups: Uncomplicated sepsis and complicated sepsis (severe sepsis and septic shock). IG% and other biomarkers were evaluated and compared for predicting sepsis severity, overt disseminated intravascular coagulation (DIC) and 28 day mortality.

RESULTS

In multivariate analysis, only IG% (odd ratio [OR] 2.530, p = 0.004) and lactate (OR 4.500, p < 0.001) could discriminate between complicated and uncomplicated sepsis. The optimal cut-off value for IG% and lactate was 0.5% and 2.0 mmol/L, respectively. In subgroup analyses of complicated sepsis, IG% was related to overt DIC. However, no single biomarker could predict 28-day mortality.

CONCLUSIONS

Given that IG% reflected sepsis severity and overt DIC without additional cost, IG% could be a useful biomarker in patients with sepsis. However, there is a limitation for using it as a novel biomarker in sepsis due to the disability of prediction for 28-day mortality.

Do the flags related to immature granulocytes reported by the Sysmex XE-5000 warrant a microscopic slide review?

OBJECTIVES

The Sysmex XE-5000 instruments (Sysmex, Kobe, Japan) count immature granulocytes (IGs) and use the "Imm Gran?" flag to signal unreliable results. This study investigated the usefulness of the "Imm Gran?" flag and the analytical and diagnostic performance of the IG measurements in a side-by-side evaluation.

METHODS

In total, 408 samples were analyzed on three XE-5000 instruments. The IG count and the "Imm Gran?" flag reports from all three instruments were used for reproducibility studies. The diagnostic performance of the automated IGs and the "Imm Gran?" flag were studied by comparing the XE-5000 results with the results of the manual differential.

RESULTS

The reproducibility of the "Imm Gran?" flagging between instruments was poor (қ, 0.75-0.80). The most significant contributor to the report of the "Imm Gran?" flag was bands, and the flag played a minor role in detecting blasts. The interinstrument reproducibility of the IG counts was high (intraclass correlation, 0.99). The IG count reported by XE-5000s was higher than the manual IG count (36%-55%), and the difference and the variability tended to increase with increasing levels of IGs.

CONCLUSIONS

The "Imm Gran?" flag has a poor analytical quality and gives no substantial information on the presence of blasts in the sample. We therefore suggest reporting the automated IG count without initial microscopic slide review.

Are the review criteria for automated complete blood counts of the International Society of Laboratory Hematology suitable for all hematology laboratories?

OBJECTIVE

to verify whether the review criteria for automated blood counts suggested by the International Consensus Group for Hematology Review of the International Society for Laboratory Hematology are suitable for the Hematology Laboratory of Hospital de Clinicas, Universidade Federal do Paraná.

METHODS

initially, the review criteria of the International Society for Laboratory Hematology were adapted due to limitations in the Institution's electronic hospital records and interfacing systems. The adapted review criteria were tested using 1977 samples. After this first assessment, an additional 180 inpatient samples were analyzed to evaluate the screening criteria of the review criteria in conjunction with positive smear findings established by the institution. The performance of the review criteria was verified by determining false positive, false negative, true positive and true negative rates, sensitivity, specificity, positive predictive value, negative predictive value, microscopic review rate and efficiency.

RESULTS

initial analysis showed false negatives=6.73%, false positives=23.27%, microscopic review rate=46.03% and efficiency=70.0%. An evaluation of the screening criteria adapted from the review criteria together with the positive smear findings of the institution showed false negatives=15.5%, false positives=10.5%, microscopic review rate=37.3% and efficiency=73.8%. In both situations the safety limit (false negative <5%) recommended by the review criteria was exceeded.

CONCLUSIONS

the review criteria adapted from the International Society for Laboratory Hematology are neither suitable nor safe for use in the hematology laboratory of the Hospital de Clinicas. This implies a need to develop and validate institution-specific review criteria in order to decrease false negative results to an acceptable and safe rate for patients.

Automated Hematology Analyzers in Diagnosis of Plasmodium vivax Malaria: an Adjunct to Conventional Microscopy

Malaria is one of the most pervasive parasitic diseases ever known to mankind affecting nearly 300 million people every year. The need for rapid diagnosis of malaria in tropical and subtropical malaria endemic areas is on the rise. In this study, we evaluated the usefulness of hematology autoanalyzers, Sysmex XE-2100 & XT-2000i in the presumptive diagnosis of malaria. Our study shows that abnormalities in WBC/BASO scattergram when combined with presence of thrombocytopenia had a high sensitivity and positive predictive value in the presumptive diagnosis of Plasmodium vivax (P.vivax) malaria.

Utility of immature granulocyte percentage in pediatric appendicitis

BACKGROUND

Acute appendicitis is the most common cause of abdominal surgery in children. Adjuncts are used to help clinicians predict acute or perforated appendicitis, which may affect treatment decisions. Automated hematologic analyzers can perform more accurate automated differentials including immature granulocyte percentages (IG%). Elevated IG% has demonstrated improved accuracy for predicting sepsis in the neonatal population than traditional immature-to-total neutrophil count ratios. We intended to assess the additional discriminatory ability of IG% to traditionally assessed parameters in the differentiation between acute and perforated appendicitis.

MATERIALS AND METHODS

We identified all patients with appendicitis from July 2012-June 2013 by International Classification of Diseases-9 code. Charts were reviewed for relevant demographic, clinical, and outcome data, which were compared between acute and perforated appendicitis groups using Fisher exact and t-tests for categorical and continuous variables, respectively. We used an adjusted logistic regression model using clinical laboratory values to predict the odds of perforated appendicitis.

RESULTS

A total of 251 patients were included in the analysis. Those with perforated appendicitis had a higher white blood cell count (P=0.0063), C-reactive protein (CRP) (P<0.0001), and IG% (P=0.0299). In the adjusted model, only elevated CRP (odds ratio 3.46, 95% confidence interval 1.40-8.54) and presence of left shift (odds ratio 2.66, 95% confidence interval 1.09-6.46) were significant predictors of perforated appendicitis. The c-statistic of the final model was 0.70, suggesting fair discriminatory ability in predicting perforated appendicitis.

CONCLUSIONS

IG% did not provide any additional benefit to elevated CRP and presence of left shift in the differentiation between acute and perforated appendicitis.

Platelet dynamics during natural and pharmacologically induced torpor and forced hypothermia

Hibernation is an energy-conserving behavior in winter characterized by two phases: torpor and arousal. During torpor, markedly reduced metabolic activity results in inactivity and decreased body temperature. Arousal periods intersperse the torpor bouts and feature increased metabolism and euthermic body temperature. Alterations in physiological parameters, such as suppression of hemostasis, are thought to allow hibernators to survive periods of torpor and arousal without organ injury. While the state of torpor is potentially procoagulant, due to low blood flow, increased viscosity, immobility, hypoxia, and low body temperature, organ injury due to thromboembolism is absent. To investigate platelet dynamics during hibernation, we measured platelet count and function during and after natural torpor, pharmacologically induced torpor and forced hypothermia. Splenectomies were performed to unravel potential storage sites of platelets during torpor. Here we show that decreasing body temperature drives thrombocytopenia during torpor in hamster with maintained functionality of circulating platelets. Interestingly, hamster platelets during torpor do not express P-selectin, but expression is induced by treatment with ADP. Platelet count rapidly restores during arousal and rewarming. Platelet dynamics in hibernation are not affected by splenectomy before or during torpor. Reversible thrombocytopenia was also induced by forced hypothermia in both hibernating (hamster) and non-hibernating (rat and mouse) species without changing platelet function. Pharmacological torpor induced by injection of 5'-AMP in mice did not induce thrombocytopenia, possibly because 5'-AMP inhibits platelet function. The rapidness of changes in the numbers of circulating platelets, as well as marginal changes in immature platelet fractions upon arousal, strongly suggest that storage-and-release underlies the reversible thrombocytopenia during natural torpor. Possibly, margination of platelets, dependent on intrinsic platelet functionality, governs clearance of circulating platelets during torpor.

Immature granulocytes predict microbial infection and its adverse sequelae in the intensive care unit

BACKGROUND

We evaluated the predictive value of immature granulocyte (IG) percentage in comparison with white blood cell counts (WBC) and C-reactive protein (CRP), for infection, its invasiveness, and severity in critically ill patients.

METHODS

In 46 consecutive patients, blood samples were collected at the day (0) of a clinical suspicion of microbial infection and at days 1 and 3 thereafter. We defined infections, bloodstream infection, and septic shock within 7 days after enrollment.

RESULTS

Of the 46 patients, 31 patients had infection, 15 patients developed bloodstream infection, and 13 patients septic shock. C-reactive protein and IG percentage increased with increasing invasiveness and severity of infection, from day 0 onwards. Receiver operating characteristic analysis to predict infection showed an area under the curve of 0.66 (P=.10) for WBC vs 0.74 (P=.01) for CRP and 0.73 (P=.02) for IG percentage on day 0. Comparing WBC and CRP to WBC and IG percentage results in comparable prediction of microbial infection. Comparing WBC and CRP with WBC, CRP, and IG percentage suggests an additional early value of IG percentage, when not elevated, in ruling out infection.

CONCLUSION

Immature granulocyte percentage is a useful marker, as CRP, to predict infection, its invasiveness, and severity, in critically ill patients. However, the IG percentage adds to WBC and CRP in the early exclusion of infection and can be obtained routinely without extra blood sampling or costs.

5'-AMP impacts lymphocyte recirculation through activation of A2B receptors

Natural hibernation consists of torpid phases with metabolic suppression alternating with euthermic periods. Induction of torpor holds substantial promise in various medical conditions, including trauma, major surgery, and transplantation. Torpor in mice can be induced pharmacologically by 5'-AMP. Previously, we showed that during natural torpor, the reduction in body temperature results in lymphopenia via a reduction in plasma S1P. Here, we show that during torpor induced by 5'-AMP, there is a similar reduction in the number of circulating lymphocytes that is a result of their retention in secondary lymphoid organs. This lymphopenia could be mimicked by engagement of A(2B)Rs by a selective A(2B)R agonist (LUF6210) in the absence of changes in temperature and prevented by A(2B)R antagonists during 5'-AMP-induced torpor. In addition, forced cooling of mice led to peripheral blood lymphopenia, independent of A(2B)R signaling. The induction of torpor using 5'-AMP impacted the migration of lymphocytes within and between secondary lymphoid organs. During torpor, the homing into LNs was impaired, and two-photon intravital microscopy revealed that cell motility was decreased significantly and rapidly upon 5'-AMP administration. Furthermore, the S1P plasma concentration was reduced by 5'-AMP but not by LUF6210. S1P plasma levels restored upon arousal. Likely, the reduced migration in LNs combined with the reduced S1P plasma level substantially reduces lymphocyte egress after injection of 5'-AMP. In conclusion, 5'-AMP induces a state of pharmacological torpor in mice, during which, lymphopenia is governed primarily by body temperature-independent suppression of lymphocyte egress from LNs.

Reduction of body temperature governs neutrophil retention in hibernating and nonhibernating animals by margination

Hibernation consists of periods of low metabolism, called torpor, interspersed by euthermic arousal periods. During deep and daily (shallow) torpor, the number of circulating leukocytes decreases, although circulating cells, is restored to normal numbers upon arousal. Here, we show that neutropenia, during torpor, is solely a result of lowering of body temperature, as a reduction of circulating also occurred following forced hypothermia in summer euthermic hamsters and rats that do not hibernate. Splenectomy had no effect on reduction in circulating neutrophils during torpor. Margination of neutrophils to vessel walls appears to be the mechanism responsible for reduced numbers of neutrophils in hypothermic animals, as the effect is inhibited by pretreatment with dexamethasone. In conclusion, low body temperature in species that naturally use torpor or in nonhibernating species under forced hypothermia leads to a decrease of circulating neutrophils as a result of margination. These findings may be of clinical relevance, as they could explain, at in least part, the benefits and drawbacks of therapeutic hypothermia as used in trauma patients and during major surgery.

The usefulness of blast flags on the Sysmex XE-5000 is questionable

Hematology analyzers generate suspect flags that involve microscopic reviews to confirm the presence of pathologic cells. This study investigated the reliability of the blast flag in a side-by-side evaluation of 3 Sysmex XE-5000 instruments (Sysmex, Kobe, Japan). The repeatability of the Q values reported by each instrument for 10 replicates of the same blood samples was low (intraclass correlation coefficient [ICC] values, 0.62-0.74). The reproducibility of the Q values obtained by analyzing 408 samples on all 3 instruments was reasonable (ICC value, 0.85). In addition, a systematic difference was observed among the instruments in the level of reported Q values. With cutoff commonly being 100, the observed reproducibility of the blast flagging among the instruments was evaluated as poor (κ = 0.73). Based on the observed low performances, we question the usefulness of the Q value as a predictor of blasts and whether a blast flag reported by the XE-5000 is sufficient as a criterion for performing a microscopic review.