Hematological parameters: is there a difference between those released by the hematological analyzer and to the customer?

OBJECTIVE: This study aimed to compare the hematological parameters released by hematological analyzers with those released in customer reports. METHODS: We conducted a descriptive study in the laboratories of a medium-sized municipality in the state of Minas Gerais registered in the National Register of Health Establishments. Interviews were conducted using a questionnaire to obtain information regarding the parameters released by the analyzers and those available in the customer's report. RESULTS: Sixteen laboratories were evaluated, and none of them released all the parameters obtained from the hematological analyzers to customers. The red blood cell distribution width was released in 88% of the laboratories, atypical lymphocytes in 70%, mean platelet volume in 50%, platelet distribution width and platelet count in 20%. No laboratory released information on reticulocytes, fraction of immature reticulocytes and immature granulocytes, nucleated erythrocyte count, immature platelet fraction and reticulocyte hemoglobin, and large platelet rate. CONCLUSION: All evaluated clinical analysis laboratories had at least one parameter that was not released in the customer's report despite being released by the hematological analyzers. The lack of knowledge on the part of professionals about the clinical importance of each parameter of the complete blood count results in a loss in patient assessment, and it is important to include these parameters in the complete blood count report.

Multiparameter mobile blood analysis for complete blood count using contrast-enhanced defocusing imaging and machine vision.

Blood analysis through complete blood count is the most basic medical test for disease diagnosis. Conventional blood analysis requires bulky and expensive laboratory facilities and skilled technicians, limiting the universal medical use of blood analysis outside well-equipped laboratory environments. Here, we propose a multiparameter mobile blood analyzer combined with label-free contrast-enhanced defocusing imaging (CEDI) and machine vision for instant and on-site diagnostic applications. We designed a low-cost and high-resolution miniature microscope (size: 105 mm × 77 mm × 64 mm, weight: 314 g) that comprises a pair of miniature aspheric lenses and a 415 nm LED for blood image acquisition. The analyzer, adopting CEDI, can obtain both the refractive index distributions of the white blood cell (WBC) and hemoglobin spectrophotometric information, enabling the analyzer to supply rich blood parameters, including the five-part WBC differential count, red blood cell (RBC) count, and mean corpuscular hemoglobin (MCH) quantification with machine vision algorithms and the Lambert-Beer law. We have shown that our assay can analyze a blood sample within 10 minutes without complex staining, and measurements (30 samples) from the analyzer have a strong linear correlation with clinical reference values (significance level of 0.0001). This study provides a miniature, light weight, low-cost, and easy-to-use blood analysis technique that overcomes the challenge of simultaneously realizing FWD count, RBC count, and MCH analysis using a mobile device and has great potential for integrated surveillance of various epidemic diseases, including coronavirus infection, invermination, and anemia, especially in low- and middle-income countries.

Influence of hemolysis on nucleated red blood cells count.

INTRODUCTION: Hemolysis is a common pre-analytical factor that can influence test results. Here, we explored the influence of hemolysis on nucleated red blood cells (NRBCs) count and tried to illustrate the mechanisms underlying this interference. METHODS: From July 2019 to June 2021, 20 preanalytical hemolytic peripheral blood (PB) samples from inpatient at Tianjin Huanhu Hospital were evaluated using Sysmex XE-5000 automated hematology analyzer. When NRBC enumeration was positive and a flag was triggered, a 200-cell differential count was performed by experienced technologists on microscopic review. When the manual count was inconsistent with automated enumeration, samples will be re-collected. Plasma exchange test was performed to verify the influence factors of hemolyzed samples and the mechanical hemolysis experiment mimicking hemolysis that might occur during blood collection was performed to illustrate the underlying mechanisms. RESULTS: Hemolysis led to false-positive NRBC count and the value of NRBC was positively correlated with the degree of hemolysis. Hemolysis specimen shared a common scatter diagram: a "beard" on WBC/ basophil (BASO) channel and a "blue scatter line" on immature myeloid information (IMI) channel. Lipid droplets were found above the hemolysis specimen after centrifugation. Plasma exchange experiment confirmed that these lipid droplets interfered with NRBCs count. Mechanical hemolysis experiment implied further that broken red blood cells (RBCs) released lipid droplets causing the false-positive NRBCs count. CONCLUSION: In the present study, we firstly found that hemolysis could lead to false-positive NRBCs enumeration, which was associated with lipid droplets released from broken RBCs during hemolysis.

Comparison of six microscopic methods and two operators for estimation of white and red blood cells in canine urine sediment.

BACKGROUND: Little information is currently available about the analytical variability of urinalysis. OBJECTIVE: We aimed to compare results obtained by two operators using six microscopic methods in the quantification of urinary leukocytes (WBC) and erythrocytes (RBC). METHODS: Forty urine samples (10 mL) were centrifuged (450g, 5 minutes) and resuspended in 0.5 mL of supernatant. Two operators with different expertise in urinalysis interpreted sediment results using the six methods, obtained by combining the use of microscope slides (Slide) or counting chambers (Chamber) with three different techniques: bright-field (BF) microscopy, phase-contrast (PC) microscopy, and stained sediment (SS) evaluations. The mean WBC and RBC counts from 10 fields (Slide) or squares (Chamber) observed at 400× were used to calculate the difference and agreement between operators and methods. We also estimated the concordance between methods in classifying microhematuric or pyuric samples. RESULTS: Operator 2 counted significantly lower WBC counts using Slide+BF (P = 0.009) and Slide+PC (P = 0.001) than Operator 1, whereas no inter-operator differences were recorded for RBC counts. The concordance between the operators ranged from "good" to "very good." No differences or biases were found for WBC counts among the methods, and concordances were "good" to "very good"; proportional biases were found for RBC counts between Slide+BF vs Slide+SS and Slide+PC vs Slide+SS. Concordance measurements for RBC counts ranged from "good" to "very good." CONCLUSIONS: All methods yielded good reproducibility among operators, although stained SS evaluations allowed better identification of WBC by the inexperienced operator. However, we suspected that the SS preparations affected RBC counts. All other methods yielded reproducible WBC and RBC counts.

Performance evaluation of UF-4000 body fluid mode for automated body fluid cell counting.

BACKGROUND: Cytological analysis of body fluids (BF) provides important information for diagnosis in various medical conditions. We evaluated the analytical performance of the UF-4000 BF mode for ascitic, cerebrospinal, pleural, synovial and continuous ambulatory peritoneal dialysis fluids compared to light microscopy counting (LM). MATERIALS AND METHODS: 223 consecutive BF were analyzed by UF-4000 and results were compared using Pearson's correlation, Bland-Altman analysis, and contingence tests at relevant cut-off values. This study also included the evaluation of precision, linearity, and carryover. RESULTS: For white and red blood cells (WBC, RBC) counts in all BF, correlation was excellent with Pearson's coefficients R2 > 0,98. Bland-Altman analysis didn't reveal significant differences with limited bias for WBC ranging from -10 to -1 WBC/µL and bias ranging from -43 to -6/µL for RBC. At specific cut-off values for WBC, Se and Spe were 100% except for ascites (Spe = 98%) due to two false positive. Precision evaluated at three concentration levels was good for each parameter (WBC < 10%). Linearity was excellent for WBC (R2 > 0,99) and carryover negligible (<0,004%). CONCLUSION: UF-4000 BF mode is a good alternative to manual LM for BF cell counting. This automated method gives rapid and accurate results which is important for therapeutic decisions.

Red Blood Cell and Endothelial eNOS Independently Regulate Circulating Nitric Oxide Metabolites and Blood Pressure.

BACKGROUND: Current paradigms suggest that nitric oxide (NO) produced by endothelial cells (ECs) through endothelial nitric oxide synthase (eNOS) in the vessel wall is the primary regulator of blood flow and blood pressure. However, red blood cells (RBCs) also carry a catalytically active eNOS, but its role is controversial and remains undefined. This study aimed to elucidate the functional significance of RBC eNOS compared with EC eNOS for vascular hemodynamics and nitric oxide metabolism. METHODS: We generated tissue-specific loss- and gain-of-function models for eNOS by using cell-specific Cre-induced gene inactivation or reactivation. We created 2 founder lines carrying a floxed eNOS (eNOSflox/flox) for Cre-inducible knockout (KO), and gene construct with an inactivated floxed/inverted exon (eNOSinv/inv) for a Cre-inducible knock-in (KI), which respectively allow targeted deletion or reactivation of eNOS in erythroid cells (RBC eNOS KO or RBC eNOS KI mice) or in ECs (EC eNOS KO or EC eNOS KI mice). Vascular function, hemodynamics, and nitric oxide metabolism were compared ex vivo and in vivo. RESULTS: The EC eNOS KOs exhibited significantly impaired aortic dilatory responses to acetylcholine, loss of flow-mediated dilation, and increased systolic and diastolic blood pressure. RBC eNOS KO mice showed no alterations in acetylcholine-mediated dilation or flow-mediated dilation but were hypertensive. Treatment with the nitric oxide synthase inhibitor Nγ-nitro-l-arginine methyl ester further increased blood pressure in RBC eNOS KOs, demonstrating that eNOS in both ECs and RBCs contributes to blood pressure regulation. Although both EC eNOS KOs and RBC eNOS KOs had lower plasma nitrite and nitrate concentrations, the levels of bound NO in RBCs were lower in RBC eNOS KOs than in EC eNOS KOs. Reactivation of eNOS in ECs or RBCs rescues the hypertensive phenotype of the eNOSinv/inv mice, whereas the levels of bound NO were restored only in RBC eNOS KI mice. CONCLUSIONS: These data reveal that eNOS in ECs and RBCs contribute independently to blood pressure homeostasis.

Nucleated red blood cells participate in myocardial regeneration in the toad Bufo Gargarizan Gargarizan.

Heart regeneration is negligible in humans and mammals but remarkable in some ectotherms. Humans and mammals lack nucleated red blood cells (NRBCs), while ectotherms have sufficient NRBCs. This study used Bufo gargarizan gargarizan, a Chinese toad subspecies, as a model animal to verify our hypothesis that NRBCs participate in myocardial regeneration. NRBC infiltration into myocardium was seen in the healthy toad hearts. Heart needle-injury was used as an enlarged model of physiological cardiomyocyte loss. It recovered quickly and scarlessly. NRBC infiltration increased during the recovery. Transwell assay was done to in vitro explore effects of myocardial injury on NRBCs. In the transwell system, NRBCs could infiltrate into cardiac pieces and could transdifferentiate toward cardiomyocytes. Heart apex cautery caused approximately 5% of the ventricle to be injured to varying degrees. In the mildly to moderately injured regions, NRBC infiltration increased and myocardial regeneration started soon after the inflammatory response; the severely damaged region underwent inflammation, scarring, and vascularity before NRBC infiltration and myocardial regeneration, and recovered scarlessly in four months. NRBCs were seen in the newly formed myocardium. Enzyme-linked immunosorbent assay and Western blotting showed that the levels of tumor necrosis factor-α, interleukin- 1ß, 6, and11, cardiotrophin-1, vascular endothelial growth factor, erythropoietin, matrix metalloproteinase- 2 and 9 in the serum and/or cardiac tissues fluctuated in different patterns during the cardiac injury-regeneration. Cardiotrophin-1 could induce toad NRBC transdifferentiation toward cardiomyocytes in vitro. Taken together, the results suggest that the NRBC is a cell source for cardiomyocyte renewal/regeneration in the toad; cardiomyocyte loss triggers a series of biological processes, facilitating NRBC infiltration and transition to cardiomyocytes. This finding may guide a new direction for improving human myocardial regeneration.

An evaluation of existing manual blood film schistocyte quantitation guidelines and a new proposed method.

Schistocytosis is the morphological hallmark of the microangiopathic haemolytic anaemia of thrombotic microangiopathy (TMA). Consensus guidelines for manual schistocyte quantitation are available, but limited research has evaluated them. The 2012 International Council for Standardization in Haematology (ICSH) recommends a schistocyte quantitation of 1% as a robust cut-off for significance, with the quantitation including helmet, crescent, triangle and keratocyte poikilocytes; and microspherocytes only in the presence of helmets, crescents/triangles, and keratocytes. We aimed to evaluate the relative contribution of these different poikilocytes to schistocyte counting; compare the ICSH method with our proposed method which counts only cells most specific for red cell fragmentation (helmet, crescent and triangular schistocytes); and evaluate inter- and intra-observer agreement. Blood films were sourced from the Australian Snakebite Project, including non-envenomed and envenomed cases, with and without TMA. In blood films across the range of schistocytosis, the predominant poikilocytes present were helmets and crescents. Triangles, keratocytes and microspherocytes were typically only present when ICSH schistocyte count was >1%. With results dichotomised as <1.0% or ≥1.0%, our proposed new method versus the ICSH method showed almost perfect agreement [observed agreement 95%, Cohen's kappa (κ)=0.84, SE 0.04, 95% CI 0.76-0.92, p<0.005]. Inter-observer strength of agreement for our method was moderate (Fleiss' κ for comparisons between three non-unique microscopists κ=0.50, SE 0.05, 95% CI 0.41-0.59, p<0.005). Intra-observer reproducibility assessed in two microscopists ranged from substantial (Cohen's κ=0.71, SE 0.08, 95% CI 0.55-0.86, p<0.005) to borderline almost perfect agreement (Cohen's κ=0.81, SE 0.07, 95% CI 0.68-0.93, p<0.005). Schistocyte quantitation using our new method is simpler than the 2012 ICSH method and had almost perfect agreement. Our finding of moderate inter-observer agreement in quantitating helmet, triangle and crescent schistocytes is applicable to both the ICSH and our newly proposed method. This finding underscores the importance of clinicopathological correlation and repeated examinations in the context of a clinically suspected TMA.

The impact of blood donation on blood counts and ferritin levels: A multi-center study from the Eastern Mediterranean region.

Regular donation of whole blood may lead to iron deficiency. In this study, we aimed to assess the impact of frequent whole blood donation on hematological parameters. Whole blood donors were enrolled from four blood banks located in Saudi Arabia, United Arab Emirates (UAE), Libya and Oman, between 2016 and 2017. SPSS version 21.0 was used to generate descriptive and inferential statistics. A total number of 3096 blood donors were screened (males 93.8 %, females; 6.2 %), with a mean donor age of 35.29 ± 9.31 years. For male blood donors, the majority (1073) had 1-3 previous donations. Increased frequency of donations was significantly associated with increases in age and weight, decreases in Hemoglobin (Hb) and ferritin measures, and increases in Red Blood Cells (RBC) counts. A General Linear Model (GLM) adjusted for age and weight indicated negative impacts on White Blood Cells (WBC) counts and ferritin. A weak correlation between the Hb and ferritin levels was observed (r = 0.160, P > 0.001). For female donors, the majority (63 out of 114) were first time donors. Increased frequency of donations was significantly associated with an increase in age and a decrease in HCT readings. A GLM adjusted for age and weight indicated a negative impact on ferritin. A strong correlation was observed between the Hb and ferritin levels for the most frequent female donors (r = 0.636, P > 0.001). In conclusion, regular whole blood donation impacts hematological parameters in particular the levels of ferritin in the serum.

Morphometry and Stiffness of Red Blood Cells-Signatures of Neurodegenerative Diseases and Aging.

Human red blood cells (RBCs) are unique cells with the remarkable ability to deform, which is crucial for their oxygen transport function, and which can be significantly altered under pathophysiological conditions. Here we performed ultrastructural analysis of RBCs as a peripheral cell model, looking for specific signatures of the neurodegenerative pathologies (NDDs)-Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD), utilizing atomic force (AFM) and conventional optical (OM) microscopy. We found significant differences in the morphology and stiffness of RBCs isolated from patients with the selected NDDs and those from healthy individuals. Neurodegenerative pathologies' RBCs are characterized by a reduced abundance of biconcave discoid shape, lower surface roughness and a higher Young's modulus, compared to healthy cells. Although reduced, the biconcave is still the predominant shape in ALS and AD cells, while the morphology of PD is dominated by crenate cells. The features of RBCs underwent a marked aging-induced transformation, which followed different aging pathways for NDDs and normal healthy states. It was found that the diameter, height and volume of the different cell shape types have different values for NDDs and healthy cells. Common and specific morphological signatures of the NDDs were identified.

Emerging Microfluidic Technologies for the Detection of Circulating Tumor Cells and Fetal Nucleated Red Blood Cells.

Blood tests have been a powerful tool for the clinical analysis of many diseases. With the advances in microfluidic technology, two more specific indicators from the circulation system, namely, emerging "liquid biopsy" of circulating tumor cells (CTCs) and fetal nucleated red blood cells (fNRBCs), can be screened and analyzed as a simple blood test for the noninvasive diagnosis of cancers as well as fetal disorders. The unique feature of precisely manipulating a trace of fluid endows microfluidic devices with the ability to isolate CTCs or fNRBCs from numerous blood cells with high performance, which undoubtedly facilitates biomedical applications of these two kinds of rare cells. In this review, advanced developments in microfluidic technologies focusing on the detection and sorting of rare CTCs and fNRBCs from peripheral blood are summarized. The development of microfluidic devices incorporated with various multifunctional microstructures and nanomaterials for enhancing the sensitivity, purity, and viability of CTC or fNRBC detection enables CTC molecular analysis and fNRBC-based noninvasive prenatal diagnosis (NIPD). These microfluidics-based approaches provide great potential opportunities in noninvasive cancer diagnosis or NIPD applications.

Cargo-laden erythrocyte ghosts target liver mediated by macrophages.

Liver-targeted cargo delivery possesses great potential for the treatment of liver disease. It is urgent to find an efficient and biocompatible liver targeted delivery system. This study focused on the liver targeting properties of erythrocyte ghosts and its possible mechanism. Herein, we optimized conditions to fabricate human and mouse erythrocyte ghosts with sufficient room capable of incorporating various model substances. Erythrocyte ghosts are biocompatible cargo carriers because it is derived from autologous red blood cells (RBCs), and the cell size, zeta potential, and biconcave-disk shape of the ghosts were consistent with those of RBCs. An in vivo imaging system and positron emission tomography/computed tomography imaging showed that the ghosts were captured mainly in the liver by intravenous injection of fluorescence or 18F-fluorodeoxyglucose (FDG)-labelled ghosts into mice. In contrast, the main concentration of naked octreotide was trapped in the lungs while naked 18F-FDG was trapped in the heart. However, the concentration of cargo-loaded ghosts decreased significantly in the liver in macrophage-depleted mice. Accordingly, in vitro experiments showed that higher phosphatidylserine exposure was observed in the ghosts (38.9 %) compared to normal erythrocytes (0.69 %), and the phagocytic activity of the macrophage RAW 264.7. on the ghosts was significantly higher than that of normal erythrocytes (p < 0.001). Together they indicate that erythrocyte ghosts show liver targeting properties, and possibly owing to macrophage phagocytosis. This promising and effective therapeutic delivery system may provide therapeutic benefits for liver disease.

Development and Internal Validation of Model Predicting Postoperative Blood Loss Risk Among Children with Pulmonary Atresia Undergoing Cardiopulmonary Bypass.

To develop and internally validate nomogram predicting postoperative blood loss risk among pediatric patients with pulmonary atresia (PA) undergoing cardiopulmonary bypass (CPB). All patients aged from 6 months to 6 years with PA who underwent surgery at Fuwai Hospital from June 2015 to December 2019 were selected. And the prediction nomogram model was developed in the training set based on the selected patients. The demographic characteristics and laboratory data from each enrolled patient were gathered. Postoperative blood loss was defined as a blood loss exceeding 20.0 ml/kg within the first 24 postoperative hours. The least absolute shrinkage and selection operator (LASSO) method was used to optimize feature selection for multivariate logistic regression analysis that was applied to build a nomogram composed of all the features selected in the LASSO algorithm. The concordance index (C-index), calibration plot, and decision curve analysis (DCA) were used to evaluate the discrimination, calibration, and clinical net benefit of the nomogarm, respectively. Finally, internal validation was performed using the bootstrap technique. Of the 66 pediatric patients in the training set, 21 (31.82%) and 45 (68.18%) patients were assigned into bleeding group and non-bleeding group, respectively. The first postoperative 24-h blood loss in the bleeding group was significantly higher than that in the non-bleeding group during ICU stay (P = 0.000). Multivariate logistic regression analysis showed that, the immediate postoperative prothrombin time (odds ratio = 1.419, 95% confidence interval: 1.094-1.841, P = 0.008), the immediate postoperative platelet count (odds ratio = 0.985, 95% confidence interval: 0.973-0.997, P = 0.015) and the immediate postoperative red blood cell (RBC) count (odds ratio = 0.335, 95% confidence interval: 0.166-0.667, P = 0.002) were independent predictors of postoperative blood loss risk. The model presented favorable calibration and good discrimination with satisfactory calibration curve and a C-index of 0.858 (95% confidence interval: 0.758-0.958). High C-index value of 0.837 was achieved in the internal validation. The DCA revealed that the nomogram was great clinical effect when intervention was decided among nearly the entire range of threshold probabilities. We developed and internally validated an accurate nomogram to assist in the clinical decision-making concerning the presence of postoperative blood loss in pediatric patients with PA undergoing CPB. However, the nomogram should be endorsed by external validation before it can be recommended for routine practice.

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer.

BACKGROUND: Manufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two-site appraisal of the system. STUDY DESIGN AND METHODS: Performance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration. RESULTS: Linearity studies up to 19 000 RBCs/µL demonstrated good correlation between expected and observed results (R2 ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R2 = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/µL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/µL) than those produced with the buffy coat method either manually (median, 681 RBCs/µL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/µL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/µL were also detected by the BB mode. CONCLUSION: The BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Evaluation of machine learning-driven automated Kleihauer-Betke counting: A method comparison study.

INTRODUCTION: The Kleihauer-Betke (KB) test is the diagnostic standard for the quantification of fetomaternal hemorrhage (FMH). Manual analysis of KB slides suffers from inter-observer and inter-laboratory variability and low efficiency. Flow cytometry provides accurate quantification of FMH with high efficiency but is not available in all hospitals or at all times. We have developed an automated KB counting system that uses machine learning to identify and distinguish fetal and maternal red blood cells (RBCs). In this study, we aimed to evaluate and compare the accuracy, precision, and efficiency of the automated KB counting system with manual KB counting and flow cytometry. METHODS: The ratio of fetal RBCs of the same blood sample was quantified by manual KB counting, automated KB counting, and flow cytometry, respectively. Forty patients were enrolled in this comparison study. RESULTS: Comparing the automated KB counting system with flow cytometry, the mean bias in measuring the ratio of fetal RBCs was 0.0048%, with limits of agreement ranging from -0.22% to 0.23%. Using flow cytometry results as a benchmark, results of automated KB counting were more accurate than those from manual counting, with a lower mean bias and narrower limits of agreement. The precision of automated KB counting was higher than that of manual KB counting (intraclass correlation coefficient 0.996 vs 0.79). The efficiency of automated KB counting was 200 times that of manual counting by the certified technologists. CONCLUSION: Automated KB counting provides accurate and precise FMH quantification results with high efficiency.

The Erythropoetin rs1617640 Gene Polymorphism Associates with Hemoglobin Levels, Hematocrit and Red Blood Cell Count in Patients with Peripheral Arterial Disease.

BACKGROUND: Erythropoietin has a pivotal role in erythropoiesis and angiogenesis. A common polymorphism (rs1617640, A > C) in the promoter of the erythropoietin gene (EPO) has been associated with erythropoietin expression and microvascular complications of diabetes. We aimed to analyze the potential role of this polymorphism in the pathogenesis of peripheral arterial disease (PAD). METHODS: EPO genotypes and laboratory markers for erythropoiesis were determined in 945 patients with PAD. RESULTS: The minor EPO rs1617640 C-allele was associated in an allele-dose-dependent manner with hemoglobin levels (p = 0.006), hematocrit (p = 0.029), and red blood cell count (p = 0.003). In a multivariate linear regression analysis including conventional risk factors diabetes, sex, and smoking, EPO genotypes were furthermore associated with age at onset of PAD symptoms (p = 0.009). CONCLUSIONS: The EPO rs1617640 gene polymorphism affects erythropoiesis, leads to an earlier onset of PAD, and is a potential biomarker for the pathogenesis of this disease.

Laboratory Findings Associated With Severe Illness and Mortality Among Hospitalized Individuals With Coronavirus Disease 2019 in Eastern Massachusetts.

Importance: The coronavirus disease 2019 (COVID-19) pandemic has placed unprecedented stress on health systems across the world, and reliable estimates of risk for adverse hospital outcomes are needed. Objective: To quantify admission laboratory and comorbidity features associated with critical illness and mortality risk across 6 Eastern Massachusetts hospitals. Design, Setting, and Participants: Retrospective cohort study of all individuals admitted to the hospital who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by polymerase chain reaction across these 6 hospitals through June 5, 2020, using hospital course, prior diagnoses, and laboratory values in emergency department and inpatient settings from 2 academic medical centers and 4 community hospitals. The data were extracted on June 11, 2020, and the analysis was conducted from June to July 2020. Exposures: SARS-CoV-2. Main Outcomes and Measures: Severe illness defined by admission to intensive care unit, mechanical ventilation, or death. Results: Of 2511 hospitalized individuals who tested positive for SARS-CoV-2 (of whom 50.9% were male, 53.9% White, and 27.0% Hispanic, with a mean [SD ]age of 62.6 [19.0] years), 215 (8.6%) were admitted to the intensive care unit, 164 (6.5%) required mechanical ventilation, and 292 (11.6%) died. L1-regression models developed in 3 of these hospitals yielded an area under the receiver operating characteristic curve of 0.807 for severe illness and 0.847 for mortality in the 3 held-out hospitals. In total, 212 of 292 deaths (72.6%) occurred in the highest-risk mortality quintile. Conclusions and Relevance: In this cohort, specific admission laboratory studies in concert with sociodemographic features and prior diagnosis facilitated risk stratification among individuals hospitalized for COVID-19.

Hematocrit, hemoglobin and red blood cells are associated with vascular function and vascular structure in men.

High and low hematocrit (Hct) and hemoglobin (Hb) levels are associated with the risk of cardiovascular disease. The purpose of this study was to determine the relationships of Hct, Hb and red blood cells (RBCs) with vascular function and structure. We measured flow-mediated vasodilation (FMD), nitroglycerin-induced vasodilation (NID), brachial intima media thickness (IMT), and brachial-ankle pulse wave velocity (baPWV) in 807 men. The subjects were divided into six groups according to the levels of Hct, Hb and RBCs. NID was highest in the 46.0-48.9% Hct group among the six groups according to Hct levels. Brachial IMT was lowest in the 46.0-48.9% Hct group among the six groups. There were no significant differences in FMD and baPWV among the six groups. We used 46.0-48.9% Hct as a reference to define the lower tertile. The adjusted odds ratio of being in the low tertile of NID was significantly higher in the < 42.9% and ≥ 49.0% Hct groups. Adjusted odds ratio of being in the low tertile of brachial IMT was significantly lower in the < 39.9% Hct groups. Similar results were obtained for Hb and RBCs. Low and high levels of Hct, Hb and RBCs were associated with vascular smooth muscle dysfunction, and low Hct levels were associated with abnormal vascular structure. Increases in the levels of Hct, Hb and RBCs within normal ranges may have beneficial effects on the vasculature.