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Laboratory approach to investigation of anemia with a focus on pyruvate kinase deficiency.
Agarwal, AM, Rets, A
International journal of laboratory hematology. 2020;:107-112
Abstract
Anemia is a major health burden worldwide and affects approximately one-third of world's population. It is not a diagnosis; it is a manifestation of an underlying pathophysiology leading to either decreased hemoglobin (Hb), hematocrit (Hct), or red blood cells (RBCs). Iron deficiency anemia is still the most common cause of anemia worldwide. The symptoms are usually due to the underlying compensatory responses to decrease in oxygen delivery to the tissues. Laboratory investigation should start with complete blood count (CBC), reticulocyte count (RC), and peripheral smear evaluation. Further testing depends on these indices, that is, iron parameters and hemoglobinopathies/thalassemia evaluation in microcytic hypochromic anemia, vitamin B12, and folic acid level in macrocytic anemia. Increased RC denotes adequate bone marrow response and points toward hemolytic process and vice versa. Anemia diagnosis can be complex and confusing for the practicing physician. This review tries to give a practical simplistic approach to the diagnosis, focusing mainly on the basic parameters, that is, CBC, RC, and peripheral smear etc. Moreover, we have also tried to provide an update on the pyruvate kinase deficiency, as there has been recent exciting development in the management of these patients.
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The Role of Reticulocyte Hemoglobin Content for Diagnosis of Iron Deficiency and Iron Deficiency Anemia, and Monitoring of Iron Therapy: a Literature Review.
Gelaw, Y, Woldu, B, Melku, M
Clinical laboratory. 2019;(12)
Abstract
BACKGROUND The diagnosis of iron deficiency anemia is still complicated and most of the tests have drawbacks. Bone marrow examination, the gold standard for the diagnosis of iron deficiency and iron deficiency anemia, is a painful, invasive, and costly procedure. Other methods are also used to diagnose iron deficiency and iron deficiency anemia; soluble transferrin receptor, serum iron, serum ferritin, and transferrin saturation are most common biomarkers of iron status that are frequently affected by inflammation, chronic diseases, and in the normal aging process (except soluble transferrin receptor). All are less available compared to complete blood count with reticulocyte hemoglobin content (CHr). Reticulocytes have a normal life span of one or two days in the circulation. CHr is a good indication of iron availability and an early marker of iron deficient erythropoiesis which can be obtained readily using automated blood cell analyzers. Therefore, the main objective of the current review is to assess the role of CHr for diagnosis of iron deficiency, iron deficiency anemia, and monitoring of iron therapy. METHODS Studies published in English were searched using the National Library of Medicine, PubMed, and Google scholar databases. RESULTS According to this review, CHr has a moderate sensitivity and specificity for diagnosing iron deficiency, and is less affected by inflammation than serum iron, transferrin saturation, and ferritin and is an early predictor of treatment response. It is used in screening of iron deficiency, diagnosis of iron deficiency anemia, and diagnosis of functional iron deficiency anemia in acute or chronic diseases or inflammation. CHr is also important in treatment monitoring. It is useful for early measurement of response to iron therapy, increasing within days of the initiation of iron therapy. It helps monitoring of intravenous iron supplementation, recombinant human erythropoie¬tin therapy, and oral iron therapy in hemodialysis and non-hemodialysis patients, and children. CONCLUSIONS It is easy to analyze, less time consuming, and less expensive than bone iron examination and iron biochemical tests. However, there is no standardized cutoff point and different researchers use varying cutoff values which affects its accuracy in diagnosing iron deficiency and it should therefore be standardized. Moreover, since CHr can be affected with any conditions that cause iron restricted erythropoiesis, further analysis may be needed.
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Variation in hemoglobin across the life cycle and between males and females.
Jorgensen, JM, Crespo-Bellido, M, Dewey, KG
Annals of the New York Academy of Sciences. 2019;(1):105-125
Abstract
WHO recommendations for hemoglobin (Hb) cutoffs to define anemia are based on a handful of studies conducted in the 1960s that did not include participants from all life stages. To evaluate whether there is a need to update Hb cutoffs, we conducted a narrative review of the literature to identify more recent studies that have reported Hb cutoffs in males and females in various life stages. We compiled information from 60 studies conducted around the globe between 1975 and 2018. Many studies reported cutoffs that were similar to WHO recommendations, but cutoffs identified in studies of infants, young children, premenopausal women, and the elderly tended to be lower than WHO recommendations, while cutoffs identified in studies of men tended to be higher than WHO cutoffs. Few studies excluded individuals with iron deficiency or inflammation, which limits the conclusions that can be drawn regarding normal reference ranges. Further research using more stringent exclusion criteria is needed to develop revised recommendations for Hb cutoffs to define anemia.
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Sickle cell retinopathy. A focused review.
Abdalla Elsayed, MEA, Mura, M, Al Dhibi, H, Schellini, S, Malik, R, Kozak, I, Schatz, P
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2019;(7):1353-1364
Abstract
PURPOSE To provide a focused review of sickle cell retinopathy in the light of recent advances in the pathogenesis, multimodal retinal imaging, management of the condition, and migration trends, which may lead to increased prevalence of the condition in the Western world. METHODS Non-systematic focused literature review. RESULTS Sickle retinopathy results from aggregation of abnormal hemoglobin in the red blood cells in the retinal microcirculation, leading to reduced deformability of the red blood cells, stagnant blood flow in the retinal precapillary arterioles, thrombosis, and ischemia. This may be precipitated by hypoxia, acidosis, and hyperosmolarity. Sickle retinopathy may result in sight threatening complications, such as paracentral middle maculopathy or sequelae of proliferative retinopathy, such as vitreous hemorrhage and retinal detachment. New imaging modalities, such as wide-field imaging and optical coherence tomography angiography, have revealed the microstructural features of sickle retinopathy, enabling earlier diagnosis. The vascular growth factor ANGPTL-4 has recently been identified as a potential mediator of progression to proliferative retinopathy and may represent a possible therapeutic target. Laser therapy should be considered for proliferative retinopathy in order to prevent visual loss; however, the evidence is not very strong. With recent development of wide-field imaging, targeted laser to ischemic retina may prove to be beneficial. Exact control of intraoperative intraocular pressure, including valved trocar vitrectomy systems, may improve the outcomes of vitreoretinal surgery for complications, such as vitreous hemorrhage and retinal detachment. Stem cell transplantation and gene therapy are potentially curative treatments, which may prevent retinopathy. CONCLUSIONS There is lack of evidence regarding the optimal management of sickle retinopathy. Further study is needed to determine if recent progress in the understanding of the pathophysiology and diagnosis of sickle retinopathy may translate into improved management and outcome.
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Methods and analyzers for hemoglobin measurement in clinical laboratories and field settings.
Whitehead, RD, Mei, Z, Mapango, C, Jefferds, MED
Annals of the New York Academy of Sciences. 2019;(1):147-171
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Abstract
This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. We conducted a literature review for methods used to measure Hb in clinical laboratories and field settings. We described methods to measure Hb and factors influencing results. Automated hematology analyzer (AHA) was reference for all Hb comparisons using evaluation criteria of ±7% set by College of American Pathologists (CAP) and Clinical Laboratory Improvement Amendments (CLIA). Capillary fingerprick blood usually produces higher Hb concentrations compared with venous blood. Individual drops produced lower concentrations than pooled capillary blood. Compared with the AHA: (1) overall cyanmethemoglobin (1.0-8.0 g/L), WHO Colour Scale (0.5-10.0 g/L), paper-based devices (5.0-7.0 g/L), HemoCue® Hb-201 (1.0-16.0 g/L) and Hb-301 (0.5-6.0 g/L), and Masimo Pronto® (0.3-14.0 g/L) overestimated concentrations; (2) Masimo Radical®-7 both under- and overestimated concentrations (0.3-104.0 g/L); and (3) other methods underestimated concentrations (2.0-16.0 g/L). Most mean concentration comparisons varied less than ±7% of the reference. Hb measurements are influenced by several analytical factors. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.This paper describes and compares methods and analyzers used to measure hemoglobin (Hb) in clinical laboratories and field settings. With few exceptions, mean concentration bias was within ±7%, suggesting acceptable performance. Appropriate, high-quality methods in all settings are necessary to ensure the accuracy of Hb measurements.
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Iron Deficiency in Heart Failure: An Overview.
von Haehling, S, Ebner, N, Evertz, R, Ponikowski, P, Anker, SD
JACC. Heart failure. 2019;(1):36-46
Abstract
Iron deficiency is an extremely common comorbidity in patients with heart failure, affecting up to 50% of all ambulatory patients. It is associated with reduced exercise capacity and physical well-being and reduced quality of life. Cutoff values have been identified for diagnosing iron deficiency in heart failure with reduced ejection fraction as serum ferritin, <100 μg/l, or ferritin, 100 to 300 μg/l, with transferrin saturation of <20%. Oral iron products have been shown to have little efficacy in heart failure, where the preference is intravenous iron products. Most clinical studies have been performed using ferric carboxymaltose with good efficacy in terms of improvements in 6-min walk test distance, peak oxygen consumption, quality of life, and improvements in New York Heart Association functional class. Data from meta-analyses also suggest beneficial effects for hospitalization rates for heart failure and reduction in cardiovascular mortality rates. A prospective trial to investigate effects on morbidity and mortality is currently ongoing. This paper highlights current knowledge of the pathophysiology of iron deficiency in heart failure, its prevalence and clinical impact, and its possible treatment options.
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Use and interpretation of hemoglobin concentrations for assessing anemia status in individuals and populations: results from a WHO technical meeting.
Garcia-Casal, MN, Pasricha, SR, Sharma, AJ, Peña-Rosas, JP
Annals of the New York Academy of Sciences. 2019;(1):5-14
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Abstract
Anemia is an important public health problem that negatively affects health of individuals and economic potential of populations. An accurate case definition is critical for understanding burden and epidemiology of anemia, for planning public health interventions, and for clinical investigation and treatment of patients. The current threshold hemoglobin concentrations for diagnosis of anemia were proposed in 1968 and based on studies predominantly of Caucasian adult populations in Europe and North America. The World Health Organization is undertaking a project to review global guidelines for anemia. We describe the process of obtaining input from technical experts, researchers, blood bank experts, policy makers, and program implementers to identify key information or knowledge gaps for anemia diagnosis. From this scoping exercise, six priority areas were identified on diverse topics related to the use and interpretation of hemoglobin concentrations to diagnose anemia in individuals and populations. A call for authors was conducted to produce background, review, and research papers across priority topics. This paper summarizes the first technical meeting, which included commissioned papers as well as case studies, describes key data gaps identified, and describes the next steps in the guideline development process to assess available evidence and define knowledge gaps to improve anemia characterization.
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Anemia and acute coronary syndrome: current perspectives.
Stucchi, M, Cantoni, S, Piccinelli, E, Savonitto, S, Morici, N
Vascular health and risk management. 2018;:109-118
Abstract
Reference hemoglobin (Hb) values for the definition of anemia are still largely based on the 1968 WHO Scientific Group report, which established a cutoff value of <13 g/dL for adult men and <12 g/dL for adult nonpregnant women. Subsequent studies identified different normal values according to race and age. Estimated prevalence of anemia on admission in the setting of an acute coronary syndrome (ACS) is between 10% and 43% of the patients depending upon the specific population under investigation. Furthermore, up to 57% of ACS patients may develop hospital-acquired anemia (HAA). Both anemia on admission and HAA are associated with worse short- and long-term mortality, even if different mechanisms contribute to their prognostic impact. Baseline anemia can usually be traced back to preexisting disease that should be specifically investigated and corrected whenever possible. HAA is associated with clinical characteristics, medical therapy and interventional procedures, all eliciting cardiovascular adaptive response that can potentially worsen myocardial ischemia. The intrinsic fragility of anemic patients may limit aggressive medical and interventional therapy due to an increased risk of bleeding, and could independently contribute to worse outcome. However, primary angioplasty for ST elevation ACS should not be delayed because of preexisting (and often not diagnosed) anemia; delaying revascularization to allow fast-track anemia diagnosis is usually feasible and justified in non-ST-elevation ACS. Besides identification and treatment of the underlying causes of anemia, the only readily available means to reverse anemia is red blood cell transfusion. The adequate transfusion threshold is still being debated, although solid evidence suggests reserving red blood cell transfusions for patients with Hb level <8 g/dL and considering it in selected cases with Hb levels of between 8 and 10 g/dL. No evidence supports the use of iron supplements and erythropoiesis-stimulating agents in the setting of ACS.
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Anemia and coronary artery disease: pathophysiology, prognosis, and treatment.
Rymer, JA, Rao, SV
Coronary artery disease. 2018;(2):161-167
Abstract
The mechanisms, pathophysiology, and treatment of anemia in coronary artery disease (CAD) are complex. The hemodynamic changes found in the acute anemic state may contribute to progressive arterial wall and left ventricular hypertrophy if the anemic state persists chronically. We will examine the evidence for anemia as an independent risk factor for CAD events and cardiovascular mortality after percutaneous coronary intervention. We will also investigate the thresholds for appropriate blood transfusion in patients with CAD, as well as the cardiovascular outcomes associated with the utilization of a liberal versus conservative blood transfusion strategy. Although there is evidence supporting the use of intravenous iron replacement in patients with congestive heart failure, we will demonstrate the lack of evidence for iron replacement in patients with CAD. Finally, we will examine the evidence for increased cardiovascular mortality and venous thromboembolic events with the use of erythropoietin-stimulating agents in patients with CAD.
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Renal Anemia and Iron Metabolism.
Ogawa, C, Tsuchiya, K, Maeda, K, Nitta, K
Contributions to nephrology. 2018;:62-73
Abstract
Normal iron metabolism is essential for effective hemoglobin (Hb) production in the management of renal anemia. Considering that studies regarding the optimal Hb levels predated the creation of the iron management indices found in the treatment guidelines for hemodialysis (HD) patients, an increase in the Hb levels caused by intravenous iron supplementation has been used as an iron management index. However, no consideration was given to iron metabolism or the long-term safety of intravenous iron supplementation. Although iron is a vital trace element in humans, it can also be toxic, and its metabolism is carefully controlled, with several factors affecting it. Considering that the details regarding the mechanisms underlying iron metabolism have been elucidated recently, a study regarding iron management that is safe and considers iron metabolism status effective for Hb production in patients with renal anemia is warranted. This study presents information regarding iron metabolism in patients on HD, the factors that influence iron metabolism in such patients, and the problems with existing treatment guidelines in Japan, apart from discussing the optimal iron levels and optimal Hb production indices.