Term
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Definition
| A genetically determined abnormality that affects the structure or synthesis of the hemoglobin |
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Term
| Explain the basis of defects resulting in the production of abnormal hemoglobins |
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Definition
| basis of the defects is in the globin chain synthesis, the heme portion is normal |
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Term
| Hemoglobin electrophoresis |
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Definition
| can detect identify hemoglobinopathies and thalassemias. Abnormal hemoglobin has altered charged due to the change in amino acids which allows for the separation of the majority of variants from HbA at an alkaline pH |
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Term
| epidemiology of sickle cell anemia |
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Definition
| is the most common symptomatic hemoglobinopathy seen in tropical Africa, Middle East and Mediterranean regions. There is an increased frequency in places where plasmodium falciparum is common and prevalent in African Americans |
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Term
| epidemiology of Hemoglobin C disease |
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Definition
| is the third most common variant in hemoglobin. It is common in West African blacks and African Americans. |
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Term
| epidemiology of hemoglobin E disease |
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Definition
| the 2nd most common hemoglobinopathy. It is common in Southeast Asians (50% in Thailand) and can also occur in blacks. |
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Term
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Definition
| caused by a nonpolar valine in the spot where a polar glutamic acid should be (at the 6th position in the A3 helix of the beta chain) |
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Term
| Hemoglobin C disease chain defect |
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Definition
| caused by nonpolar lysine in the spot where a glutamic acid should be (at the 6th position in the A3 helix of the beta chain) |
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Term
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Definition
| can help determine the presence of abnormal hemoglobin |
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Term
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Definition
| can indicate whether anemia is present |
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Term
| RDW and erythrocyte indices |
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Definition
| can be used to distinguish hemoglobinopathies from thalessemia |
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Term
| abnormal laboratory test results associated with Homozygous HbS (SCA) |
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Definition
| The CBC will show a low hemoglobin (6.0-10.0 g/dL), a low hematocrit (18-30%), increased WBC and platelets, increased RDW, and normal MCV and MCH. The reticulocyte count will be high. |
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Term
| Peripheral blood associated with Homozygous HbS (SCA) |
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Definition
| Polychromatophilic macrocytes, variable poikliocytes (sickle cells and target cells), nucleated RBCs, and inclusions like basophilic stippling, Howell-jolly bodies and Pappenheimer bodies. |
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Term
| Hb electrophoresis associated with Homozygous HbS (SCA) |
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Definition
| (cellulose acetate) will show 85-100% HbS and a higher level of HbF than normal. |
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Term
| Screening tests associated with Homozygous HbS (SCA) |
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Definition
| The solubility test will be positive (could give false negatives in severe anemia). |
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Term
| Confirmatory tests associated with Homozygous HbS (SCA) |
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Definition
| Other laboratory tests include increased indirect bilirubin, decreased Haptoglobin, and increased uric acid and LD |
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Term
| Abnormal laboratory tests results associated with Heterozygous HbS (sickle cell trait) |
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Definition
| The CBC will show normal values, |
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Term
| Peripheral blood associated with Heterozygous HbS (sickle cell trait) |
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Definition
| no evidence of anemia or sickle cells on the peripheral blood smear. |
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Term
| Screening tests associated with Heterozygous HbS (sickle cell trait) |
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Definition
| The solubility test will be positive |
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Term
| Hb electrophoresis associated with Heterozygous HbS (sickle cell trait) |
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Definition
| Hb electrophoresis will show 35-45% HbS along with 60-65% HbA |
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Term
| Abnormal test results associated with homozygous HbC |
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Definition
| The CBC will show low hemoglobin (8.0-12.0 g/dL) and a low hematocrit (25-35%). Reticulocytes will be moderately increased |
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Term
| Peripheral blood smear associated with homozygous HbC |
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Definition
| blood smear will show folded cells, target cells and some HbC crystals. |
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Term
| Hb electrophoresis associated with homozyogous HbC |
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Definition
| Hb electrophoresis in acid citrate agar will show 90% HbC and a slight increase in HbF. |
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Term
| Peripheral blood smear associated with heterozygous HbC |
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Definition
| there might be some target cells and mild hypochromia on the blood smear |
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Term
| Hb electrophoresis associated with heterozygous HbC |
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Definition
| The Hb electrophoresis shows 60-70% HbA and 30-40% HbC |
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Term
| Peripheral blood smear associated with homozygous HbE |
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Definition
| will be microcytic hypochromic cells on the blood smear along with target cells |
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Term
| Hb electrophoresis associated with homozygous HbE |
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Definition
| The electrophoresis will show greater than 90% HbE, on cellulose acetate E migrates with A2 and C and on the citrate agar E migrates with A. |
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Term
| Laboratory tests associated with heterozyous HbE |
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Definition
| the CBC will show normal results |
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Term
| Peripheral blood smear associated with heterozygous HbE |
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Definition
| slightly microcytic cells on the peripheral blood smear |
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Term
| Hb electrophoresis associated with heterozygoud HbE |
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Definition
| The Hb electrophoresis will show 35-45% HbE with the remainder being HbA, HbA2 and HbF. |
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Term
| Laboratory results associated with Hemoglobin S/C disease |
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Definition
| patients present with a mild to moderate anemia, a decreased hematocrit (25%), a normal hemoglobin (10.0-14.0 g/dL) |
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Term
| Peripheral blood associated with Hemoglobin S/C disease |
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Definition
| normocytic normochromic peripheral blood. The peripheral blood smear shows a target cells, folded cells, boat-shaped cells, rare sickle cells and rare HbC crystals along with billiard ball cells and HbSC poikilocytes |
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Term
| Clincal findings associated with Homozygous HbS (sickle cell anemia) |
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Definition
| vaso-occlusive crisis which are recurrent (pain due to dehydration and slow blood flow), splenomegaly in children, dactylitis (painful swelling of hands and feet), slow blood flow, bacterial infections (because non-functional spleen), acute splenic sequestration (in children), and acute chest symptoms |
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Term
| Clincal findings associated with heterozygous HbS (sickle cell trait) |
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Definition
| clinical symptoms and physical exam is normal |
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Term
| Clinical findings associated with Homozygous HbC (hemoglobin C disease) |
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Definition
| usually asymptomatic, possible joint and abdominal pain, spleen is sometimes enlarged with mild to moderate anemia |
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Term
| Clinical findings associated with heterozygous HbC |
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Definition
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Term
| Clinical findings associated with Homozygous HbE (hemoglobin E disease) |
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Definition
| decreased oxygen affinity |
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Term
| Clinical findings associated with heterozygous HbE |
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Definition
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Term
| Clinical findings associated with heterozygous HbSC |
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Definition
| similar to mild sickle cell anemia, vaso-occlusive crisis and splenomegaly |
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Term
| Concentration of abnormal hemoglobins in homozygous and heterozygous conditions |
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Definition
| Abnormal hemoglobins in homozygous conditions will be synthesized twice, due to the double nature of the loci for any hemoglobin. Hemoglobin is made of two chains ( same or different), if one chain is mutated, then the other chain if it is the same will be mutated as well or it would be different as in heterozygous hemoglobin. A mutation in the beta chain is the most severe |
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Term
| Prevelence of Hb S,C and E |
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Definition
| Hemoglobin S is the most prevalent, hemoglobin E is 2nd most prevalent and hemoglobin C is the third most prevalent hemoglobinopathy |
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Term
| Hemoglobin S variants pathophysiology |
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Definition
| solubility in the deoxygenated state is markedly decreased, red blood cells have a low oxygen affinity and can lose their functional capacity, and increased fragility of the RBC membrane and Heinz body formations which decreases their life span |
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Term
| Hemoglobin C variants pathophysiology |
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Definition
| solubility is decreased, function is decreased due to crystal formation, and stability is decreased the lifespan of RBCs is less than 35 days |
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Term
| Hemoglobin E variants pathophysiology |
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Definition
| decreased solubility, decreased function, and slight decreased stability |
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Term
| Structure of the hemoglobin molecule in sickle cell anemia (SCA) and relate it to the pathophysiology of the disease |
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Definition
| The hemoglobin aggregates which make the RBC rigid and less deformable, repeated cycles of this cause disruption in cation hemeostatis. Irreversible sickled cells are removed by phagocytes but the structure decreases the cells ability to transport oxygen |
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Term
| Current therapies for SCA |
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Definition
| Eliminate vaso-occlusion crisis by re-hydrating, preventing infection, blood transfusions, long-term perfusion therapy, pharmacologic therapy to increase hemoglobin F, stem cell transplant, and gene therapy |
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Term
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Definition
| alkaline buffer at pH 8.6, cathode anode, separates HbA, HbF, HbS, and HbC into separate bands, HbD and HbG moves with HbS, HbE and HbOarab moves with HbC, first band is A2CE, second band is SDG, third band is F and fourth band is A |
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Term
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Definition
| alkaline buffer at pH 6.2, separates HbA, HbS, HbC into distinct bands, HbS and HbC migrate alone (confirms), HbD, HbE, HbG, and HbOarab migrate with HbA, order of migration is F, A, S, C, the first band is F, the second band is A, A2, D, E and G and the third band is S the forth band is C. |
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Term
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Definition
| shows anemia, RDW and RBC indices distinguish hemoglobinopathies and thalassemias |
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Term
| Isoelectric focusing and high-performance liquid chromatography |
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Definition
| help to quantify A2 and F hemoglobins |
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Term
| Solubility tests, heat precipitation tests and Heinz bodies tests |
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Definition
| are screening tests used to test for altered physical properties |
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Term
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Definition
| to determine genetic defects |
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Term
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Definition
| used to determine concentration of variant hemoglobin |
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Term
| Laboratory testing algorithm for optimizing tests used in detecting and identifying abnormal hemoglobins |
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Definition
| A solubility test should be done first; if it is positive then you know there is abnormal hemoglobin. Then a cellulose acetate Hb electrophoresis should be run, if there is an increase in first or second well, then we know that it is possible that there is HbS or HbC, a citrate agar electrophoresis should be run to confirm. |
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