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Concept: Hematocrit


Marchioli et al.(1) report in the Journal that a hematocrit target of less than 45% for therapeutic phlebotomy reduces the risk of thrombosis in patients with polycythemia vera. In the genomic era, readers may question attention given to a measurement as mundane as the hematocrit, but this study resolves a half-century of debate about the role of phlebotomy in polycythemia vera and has ramifications for diagnosis and management. Polycythemia vera is a unique myeloproliferative disorder in which there is overproduction of morphologically normal erythrocytes, granulocytes, and platelets, a phenotype that is caused by a mutation (V617F) in JAK2, encoding . . .

Concepts: Blood, Red blood cell, Hematology, Hematocrit, Polycythemia vera


Individuals with colorectal cancer (CRC) have a tendency to intestinal bleeding which may result in mild to severe iron deficiency anemia, but for many colon cancer patients hematological abnormalities are subtle. The fecal occult blood test (FOBT) is used as a pre-screening test whereby those with a positive FOBT are referred to colonscopy. We sought to determine if information contained in the complete blood count (CBC) report coud be processed automatically and used to predict the presence of occult colorectal cancer (CRC) in the setting of a large health services plan. Using the health records of the Maccabi Health Services (MHS) we reviewed CBC reports for 112,584 study subjects of whom 133 were diagnosed with CRC in 2008 and analysed these with the MeScore tool. The odds ratio for being diagnosed with CRC in 2008 was calculated with regards to the MeScore, using cutoff levels of 97% and 99% percentiles. For individuals in the highest one percentile, the odds ratio for CRC was 21.8 (95% CI 13.8 to 34.2). For the majority of the individuals with cancer, CRC was not suspected at the time of the blood draw. Frequent use of anticoagulants, the presence of other gastrointestinal pathologies and non-GI malignancies were assocaitged with false positive MeScores. The MeScore can help identify individuals in the population who would benefit most from CRC screening, including those with no clinical signs or symptoms of CRC.

Concepts: Hemoglobin, Cancer, Colorectal cancer, Anemia, Hematology, Ulcerative colitis, Hematocrit, Fecal occult blood


During exercise the cardiovascular system has to warrant substrate supply to working muscle. The main function of red blood cells in exercise is the transport of O2 from the lungs to the tissues and the delivery of metabolically produced CO2 to the lungs for expiration. Hemoglobin also contributes to the blood’s buffering capacity, and ATP and NO release from red blood cells contributes to vasodilation and improved blood flow to working muscle. These functions require adequate amounts of red blood cells in circulation. Trained athletes, particularly in endurance sports, have a decreased hematocrit, which is sometimes called “sports anemia.” This is not anemia in a clinical sense, because athletes have in fact an increased total mass of red blood cells and hemoglobin in circulation relative to sedentary individuals. The slight decrease in hematocrit by training is brought about by an increased plasma volume (PV). The mechanisms that increase total red blood cell mass by training are not understood fully. Despite stimulated erythropoiesis, exercise can decrease the red blood cell mass by intravascular hemolysis mainly of senescent red blood cells, which is caused by mechanical rupture when red blood cells pass through capillaries in contracting muscles, and by compression of red cells e.g., in foot soles during running or in hand palms in weightlifters. Together, these adjustments cause a decrease in the average age of the population of circulating red blood cells in trained athletes. These younger red cells are characterized by improved oxygen release and deformability, both of which also improve tissue oxygen supply during exercise.

Concepts: Hemoglobin, Blood, Red blood cell, Bone marrow, Anemia, Hemolytic anemia, Hematology, Hematocrit


Red cell production is primarily determined by the action of erythropoietin. Additional erythropoiesis-regulatory factors include molecules and cellular interactions occurring within the bone marrow (BM) microenvironment. Sotatercept (ACE-011) is an activin receptor ligand trap which binds several members of the TGF-β superfamily. Treatment with ACE-011 reverses bone loss and reduces the degree of osteoporosis. Surprisingly, this was accompanied by elevated hemoglobin and hematocrit levels. The mechanisms underlying the beneficial effects of ACE-011 on red cell production remain unknown. This study explores the means by which ACE-011 promotes erythropoiesis. We showed that ACE-011 does not directly affect erythroid differentiation of human CD34(+) cells in vitro. We next tested whether ACE-011 acts indirectly by affecting BM accessory cells. Conditioned media (CM) produced by BM stromal cells (SC) inhibited erythroid differentiation of CD34(+) cells while maintained their ability to proliferate. However, CM from SC treated with ACE-011 partially restored erythropoiesis coinciding with changes in the molecular and secretory profile of SC, including the expression and secretion of erythropoiesis-modulatory factors. We conclude that inhibitory factors produced by BM-SC in vitro might control erythropoiesis in vivo and that agents that reverse these microenvironmental signals may provide an approach to attenuate anemia in clinical conditions.

Concepts: Hemoglobin, Erythropoietin, Cell nucleus, Red blood cell, Bone marrow, Anemia, Hematocrit, Erythropoiesis


INTRODUCTION: The CELL-DYN Emerald is a compact bench-top hematology analyzer that can be used for a three-part white cell differential analysis. To determine its utility for analysis of human and mouse samples, we evaluated this machine against the larger CELL-DYN Sapphire and Sysmex XT2000iV hematology analyzers. METHODS: 120 human (normal and abnormal) and 30 mouse (normal and abnormal) samples were analyzed on both the CELL-DYN Emerald and CELL-DYN Sapphire or Sysmex XT2000iV analyzers. For mouse samples, the CELL-DYN Emerald analyzer required manual recalibration based on the histogram populations. RESULTS: Analysis of the CELL-DYN Emerald showed excellent precision, within accepted ranges (white cell count CV% = 2.09%; hemoglobin CV% = 1.68%; platelets CV% = 4.13%). Linearity was excellent (R(2)  ≥ 0.99), carryover was minimal (<1%), and overall interinstrument agreement was acceptable for both human and mouse samples. Comparison between the CELL-DYN Emerald and Sapphire analyzers for human samples or Sysmex XT2000iV analyzer for mouse samples showed excellent correlation for all parameters. CONCLUSION: The CELL-DYN Emerald was generally comparable to the larger reference analyzer for both human and mouse samples. It would be suitable for use in satellite research laboratories or as a backup system in larger laboratories.

Concepts: Hemoglobin, Red blood cell, Anemia, Hematocrit, Thrombocytopenia, Complete blood count, Algebraic geometry, Abbott Laboratories


The ErySep system represents an alternative to centrifuge-based whole blood (WB) separation, using gravity and filtration through hollow-fibres (0·2 µm pore size) to produce red blood cell (RBC) and plasma components. The aim of this study was to characterise the quality of ErySep RBC and plasma units compared with standard products from WB held overnight.

Concepts: Cell nucleus, Blood, Red blood cell, Blood type, Hematology, Hematocrit, Blood plasma, Blood cell


Recombinant human erythropoietin (rHuEPO) is frequently abused by athletes as a performance-enhancing drug, despite being prohibited by the World Anti-Doping Agency. Although the methods to detect blood doping, including rHuEPO injections, have improved in recent years, they remain imperfect.

Concepts: Erythropoietin, Red blood cell, World, Hematocrit, Blood doping, World Anti-Doping Agency, Drugs in sport


The last decade of military trauma care has emphasized the role of blood products in the resuscitation of hemorrhaging patients. Damage-control resuscitation advocates decreased crystalloid use and reintroduces blood components as primary resuscitative fluids. The systematic use of blood products have been described in military settings, but reports describing the use of freeze dried plasma (FDP) or red blood cells (RBCs) in civilian prehospital care are few. We describe our preliminary results after implementing RBCs and FDP into our Helicopter Emergency Medical Service (HEMS).

Concepts: Cell nucleus, Blood, Red blood cell, Hematology, Hematocrit, Emergency medical services, Emergency medical technician, Blood cell


In April 2012 we carried out a 1-year hematological study on a population of wild Japanese monkeys inhabiting the forest area of Fukushima City. This area is located 70 km from the Fukushima Daiichi Nuclear Power Plant (NPP), which released a large amount of radioactive material into the environment following the Great East Japan Earthquake of 2011. For comparison, we examined monkeys inhabiting the Shimokita Peninsula in Aomori Prefecture, located approximately 400 km from the NPP. Total muscle cesium concentration in Fukushima monkeys was in the range of 78-1778 Bq/kg, whereas the level of cesium was below the detection limit in all Shimokita monkeys. Compared with Shimokita monkeys, Fukushima monkeys had significantly low white and red blood cell counts, hemoglobin, and hematocrit, and the white blood cell count in immature monkeys showed a significant negative correlation with muscle cesium concentration. These results suggest that the exposure to some form of radioactive material contributed to hematological changes in Fukushima monkeys.

Concepts: Hemoglobin, Blood, Red blood cell, Hematology, Japan, Hematocrit, Complete blood count, Honshū


Machine learning tools identify patients with blood counts indicating greater likelihood of colorectal cancer and warranting colonoscopy referral.

Concepts: Colorectal cancer, Anemia, Machine learning, Hematocrit, Complete blood count