STUDY - Technical - New Dacian's Medicine
Anemia
(2)
Translation Draft
So, let's continue with the lab tests! From the list presented at the end of the previous post, the most important of the tests "inserted" there are hemoleucogram (HLG), reticulocyte counting and evaluation of iron reserves, which includes the dosing of serum iron, total iron binding capacity and serum ferritin. In patients with severe anaemia and abnormalities in erythrocytes morphology, important for diagnosis is the achievement of a suction and a biopsy of the bone marrow.
Let's get to the blood count! There are devices that automatically measure a number of parameters that are included in the HLG, i.e. hemoglobin, the number of erythrocytes, the volume of distribution of erythrocytes, the number of platelets and that of leukocytes. The apparatus also calculates the haematocrit (based on the number and volume of erythrocytes), the mean erythrocytic volume (EMV), the mean erythrocytic haemoglobin (HEM - relative to the number of erythrocytes), the mean concentration of erythrocytic haemoglobin (CMHE - relative to hematocrit) and the distribution volume of erythrocytes (VDE). Erythrocytic and VDE indices are used, alongside the smear in the Wright drop, to assess erythrocytic morphology.
HLG provides information on clinical stages of erythropoiesis. The level of hemoglobin and haematocrit are used to identify the presence and severity of anaemia, according to a standard set of "normal" values (in adolescents haemoglobin is considered "normal" at 130 g/l and hematocrit 40%, in male adults haemoglobin 160 g/l and hematocrit 47% and in female adults hemoglobin of 130 g/l and hematocrit of 60% with variations related to postmenopausal women where the values are 140 g/l and 42% respectively, third quarter, where the values are 120 g/l and 37% respectively - a standard deviation of +/- 20 g/l for hemoglobin and 6% for hematocrit can be "associated" with all the values presented.
There are "deviations" (in the sense of magnification) to be taken into account for adults living at high altitude or smoking more than one pack of cigarettes per day (a secondary increase in the binding of carbon monoxide to hemoglobin). It is also important to find that normal hemoglobin and haematocrit levels have a Gaussian distribution around normal mean value. Therefore, the possibility of a patient being anemic depends on how low the hematocrit and hemoglobin are compared to the reference values, as well as the prevalence of different types of anemia in the population.
For example, a haemoglobin level of less than 100 g/l in an adult woman is definitely abnormal, while a value of 110-120 g/l may not indicate anaemia. Other components of HLG can help detect and classify anaemia. Erythrocytic indices, in particular VEM, will indicate an increase (macrocytosis) or decrease (microcytosis) in the volume of erythrocytes, while HEM is sensitive to hemoglobin (hypochromia) production defects. Normal values are considered to be around the following values: for VEM 90 +/- 9 fl (1 fl = 10 at power -15 of a l), for HEM 32 +/- 2 pg, for CMHE 33 +/- 3%, VDE-CV 13 +/- 1% and for VDE-SD 42 +/- 5 fl.
Automatic counting machines are very precise in assessing the volume of distribution of erythrocytes. VEM, which is the tip of the distribution curve, is not sensitive to the appearance of small populations of macrocytes or microcytes. Measurement errors may also occur as a result of major distortion in the form of erythrocytes, erythrocytic agglutination or the presence of a very large number of leukocytes. The technician or clinician can correct measurement errors by reviewing the erythrocytes distribution curve provided by the machine and by directly inspecting the peripheral blood smear.
Peripheral blood smear may provide important information about the presence and nature of an erythropoietic defect. Careful preparation of the smear is very important. Using blades and glass blades and a centrifuge, a small drop of blood can be stretched to create a monolayer of erythrocytes. The blade thus obtained is well dried and then subjected to Wright coloration to distinguish nuclear and cytoplasmic details. If the film is too thin or too thick, the normal biconcav shape of the erythrocyteis is lost.
For this reason, it is essential that the interpretation of cellular morphology is done by inspecting the best area of the best prepared blade. In addition to erythrocytic indices, changes in cell diameter and changes in shape and content in haemoglobin are checked to identify microcytosis and macrocytosis even before major alterations of VEM, HEM or VDE occur. Blood smear is also important for describing variations in the size (anisocytosis) and shape (poikilocytosis) of the cell. The degree of anisocytosis usually correlates with the increase in VDE. Poikilocytosis suggests the existence of a defect in the maturation of erythrocytic precursors or fragmented hemolysis.
The smear can also study the existence of polychromasis, i.e. polychromatic macrocytes (cells that are slightly larger and gray blue). These are medullary reticulocytes containing RNA residues and ribosomes. They occur in circulation due to an increase in the level of erythropoietin stimulation and, for this reason, can be used as markers of the appropriate response of erythropoietin. Other individual cellular abnormalities, including the occurrence of nuclear erythrocytes, Howell-Jolly bodies, target or sickle cells, are indications of specific types of anemia.
A proper counting of reticulocytes is essential for the initial classification of any anemia. Reticulocytes are young erythrocytes containing sufficient RNA residues to be coloured and evaluated as a proportion of the circulating erythrocytes population. In the basal state, the number of reticulocytes is 1-2%, depending on the counting method. This correlates with the normal daily replacement of about 1% of the circulating erythrocytes population. The increase in the number of reticulocytes ensures a correct assessment of the production of erythrocytes in response to anaemia.
To use the number of reticulocytes as an indicator of erythrocytic production, it must first be corrected according to changes in the patient's hematocrit and the effect of erythropoietin on the early release into circulation of bone marrow erythrocytes. The correction of hematocrit (Ht) converts the percentage of reticulocytes into an absolute number. The correction of medullary reticulocytes (shift) should be applied to each patient with anaemia and a very high number of reticulocytes to provide a true index of actual erythrocytes production. A normal patient will respond to a haematocrit of less than 30% with a two- or three-fold increase in the erythrocytes production index.
Patients with severe chronic haemolytic anaemia may have an erythrocytic index five or six times higher than normal. Therefore, only this measurement will confirm that the patient has an adequate response to erythropoietin, a normal marrow and a sufficient deposit of iron to support this response. When the erythrocyte index falls below 2, it is likely that there is a defect in medullary proliferation or in the maturation of precursors.
The standard assessment of iron reserves includes the determination of serum iron concentration, total iron binding capacity (CTLF) and serum ferritin levels. The normal serum iron level is between 9 and 27 mmol/ l, while normal CTLF is 54-64 mmol/ l. For this reason, in the basal state, only 30-50% of circulating transferin is saturated with iron. Important information is provided by each test, as well as by calculating the saturation percentage. Serum ferritin is useful for assessing iron deposits in the body. Male adults have serum ferritin levels between 50-100 microg/l, which corresponds to an iron deposit of 600 - 1000 mg. Adult women have lower serum ferritin levels (15-50 microg/ l) and lower iron deposits (1- 300 mg). Low levels of serum ferritin occur when iron deposits are consumed (levels below 15 microg/ l indicate deposit emptying and iron deficiency).
Iron overload (hemochromatosis and hemosiderosis) can cause levels of 500
to 1000 mg/ l. I will complete this post with the presentation of some elements about bone marrow examination. A bone marrow sample can be obtained very easily by suction with a needle or biopsy. The highest value is in patients with hydroproliferative anaemia or an erythrocytes maturation disorder, providing important information about the cellularity and structure of the marrow, as well as on the proliferation and maturation of precursors.
The ratio between the precursors of the erythrocyte series and those of the granulocyte series (E/G ratio) is used to assess the proliferative capacity of the erythrocyte precursors. A patient with hydroproliferative anaemia and the erythrocytic index of less than 2 will present an E/G ratio of 1/3 or 1/2. In contrast, patients with hemolytic anaemia and a reticulocytic index greater than or equal to 3-5 will have an E/G ratio greater than 1. Defects of erythrocyte precursors are identified due to mismatch between the E/G ratio and the reticulocytic index. These individuals have an E/G ratio greater than 1, together with a low reticulocytic index typical of ineffective erythropoiesis in maturation disorders.
Ready for this post!
So, let's continue with the lab tests! From the list presented at the end of the previous post, the most important of the tests "inserted" there are hemoleucogram (HLG), reticulocyte counting and evaluation of iron reserves, which includes the dosing of serum iron, total iron binding capacity and serum ferritin. In patients with severe anaemia and abnormalities in erythrocytes morphology, important for diagnosis is the achievement of a suction and a biopsy of the bone marrow.
Let's get to the blood count! There are devices that automatically measure a number of parameters that are included in the HLG, i.e. hemoglobin, the number of erythrocytes, the volume of distribution of erythrocytes, the number of platelets and that of leukocytes. The apparatus also calculates the haematocrit (based on the number and volume of erythrocytes), the mean erythrocytic volume (EMV), the mean erythrocytic haemoglobin (HEM - relative to the number of erythrocytes), the mean concentration of erythrocytic haemoglobin (CMHE - relative to hematocrit) and the distribution volume of erythrocytes (VDE). Erythrocytic and VDE indices are used, alongside the smear in the Wright drop, to assess erythrocytic morphology.
HLG provides information on clinical stages of erythropoiesis. The level of hemoglobin and haematocrit are used to identify the presence and severity of anaemia, according to a standard set of "normal" values (in adolescents haemoglobin is considered "normal" at 130 g/l and hematocrit 40%, in male adults haemoglobin 160 g/l and hematocrit 47% and in female adults hemoglobin of 130 g/l and hematocrit of 60% with variations related to postmenopausal women where the values are 140 g/l and 42% respectively, third quarter, where the values are 120 g/l and 37% respectively - a standard deviation of +/- 20 g/l for hemoglobin and 6% for hematocrit can be "associated" with all the values presented.
There are "deviations" (in the sense of magnification) to be taken into account for adults living at high altitude or smoking more than one pack of cigarettes per day (a secondary increase in the binding of carbon monoxide to hemoglobin). It is also important to find that normal hemoglobin and haematocrit levels have a Gaussian distribution around normal mean value. Therefore, the possibility of a patient being anemic depends on how low the hematocrit and hemoglobin are compared to the reference values, as well as the prevalence of different types of anemia in the population.
For example, a haemoglobin level of less than 100 g/l in an adult woman is definitely abnormal, while a value of 110-120 g/l may not indicate anaemia. Other components of HLG can help detect and classify anaemia. Erythrocytic indices, in particular VEM, will indicate an increase (macrocytosis) or decrease (microcytosis) in the volume of erythrocytes, while HEM is sensitive to hemoglobin (hypochromia) production defects. Normal values are considered to be around the following values: for VEM 90 +/- 9 fl (1 fl = 10 at power -15 of a l), for HEM 32 +/- 2 pg, for CMHE 33 +/- 3%, VDE-CV 13 +/- 1% and for VDE-SD 42 +/- 5 fl.
Automatic counting machines are very precise in assessing the volume of distribution of erythrocytes. VEM, which is the tip of the distribution curve, is not sensitive to the appearance of small populations of macrocytes or microcytes. Measurement errors may also occur as a result of major distortion in the form of erythrocytes, erythrocytic agglutination or the presence of a very large number of leukocytes. The technician or clinician can correct measurement errors by reviewing the erythrocytes distribution curve provided by the machine and by directly inspecting the peripheral blood smear.
Peripheral blood smear may provide important information about the presence and nature of an erythropoietic defect. Careful preparation of the smear is very important. Using blades and glass blades and a centrifuge, a small drop of blood can be stretched to create a monolayer of erythrocytes. The blade thus obtained is well dried and then subjected to Wright coloration to distinguish nuclear and cytoplasmic details. If the film is too thin or too thick, the normal biconcav shape of the erythrocyteis is lost.
For this reason, it is essential that the interpretation of cellular morphology is done by inspecting the best area of the best prepared blade. In addition to erythrocytic indices, changes in cell diameter and changes in shape and content in haemoglobin are checked to identify microcytosis and macrocytosis even before major alterations of VEM, HEM or VDE occur. Blood smear is also important for describing variations in the size (anisocytosis) and shape (poikilocytosis) of the cell. The degree of anisocytosis usually correlates with the increase in VDE. Poikilocytosis suggests the existence of a defect in the maturation of erythrocytic precursors or fragmented hemolysis.
The smear can also study the existence of polychromasis, i.e. polychromatic macrocytes (cells that are slightly larger and gray blue). These are medullary reticulocytes containing RNA residues and ribosomes. They occur in circulation due to an increase in the level of erythropoietin stimulation and, for this reason, can be used as markers of the appropriate response of erythropoietin. Other individual cellular abnormalities, including the occurrence of nuclear erythrocytes, Howell-Jolly bodies, target or sickle cells, are indications of specific types of anemia.
A proper counting of reticulocytes is essential for the initial classification of any anemia. Reticulocytes are young erythrocytes containing sufficient RNA residues to be coloured and evaluated as a proportion of the circulating erythrocytes population. In the basal state, the number of reticulocytes is 1-2%, depending on the counting method. This correlates with the normal daily replacement of about 1% of the circulating erythrocytes population. The increase in the number of reticulocytes ensures a correct assessment of the production of erythrocytes in response to anaemia.
To use the number of reticulocytes as an indicator of erythrocytic production, it must first be corrected according to changes in the patient's hematocrit and the effect of erythropoietin on the early release into circulation of bone marrow erythrocytes. The correction of hematocrit (Ht) converts the percentage of reticulocytes into an absolute number. The correction of medullary reticulocytes (shift) should be applied to each patient with anaemia and a very high number of reticulocytes to provide a true index of actual erythrocytes production. A normal patient will respond to a haematocrit of less than 30% with a two- or three-fold increase in the erythrocytes production index.
Patients with severe chronic haemolytic anaemia may have an erythrocytic index five or six times higher than normal. Therefore, only this measurement will confirm that the patient has an adequate response to erythropoietin, a normal marrow and a sufficient deposit of iron to support this response. When the erythrocyte index falls below 2, it is likely that there is a defect in medullary proliferation or in the maturation of precursors.
The standard assessment of iron reserves includes the determination of serum iron concentration, total iron binding capacity (CTLF) and serum ferritin levels. The normal serum iron level is between 9 and 27 mmol/ l, while normal CTLF is 54-64 mmol/ l. For this reason, in the basal state, only 30-50% of circulating transferin is saturated with iron. Important information is provided by each test, as well as by calculating the saturation percentage. Serum ferritin is useful for assessing iron deposits in the body. Male adults have serum ferritin levels between 50-100 microg/l, which corresponds to an iron deposit of 600 - 1000 mg. Adult women have lower serum ferritin levels (15-50 microg/ l) and lower iron deposits (1- 300 mg). Low levels of serum ferritin occur when iron deposits are consumed (levels below 15 microg/ l indicate deposit emptying and iron deficiency).
Iron overload (hemochromatosis and hemosiderosis) can cause levels of 500
to 1000 mg/ l. I will complete this post with the presentation of some elements about bone marrow examination. A bone marrow sample can be obtained very easily by suction with a needle or biopsy. The highest value is in patients with hydroproliferative anaemia or an erythrocytes maturation disorder, providing important information about the cellularity and structure of the marrow, as well as on the proliferation and maturation of precursors.
The ratio between the precursors of the erythrocyte series and those of the granulocyte series (E/G ratio) is used to assess the proliferative capacity of the erythrocyte precursors. A patient with hydroproliferative anaemia and the erythrocytic index of less than 2 will present an E/G ratio of 1/3 or 1/2. In contrast, patients with hemolytic anaemia and a reticulocytic index greater than or equal to 3-5 will have an E/G ratio greater than 1. Defects of erythrocyte precursors are identified due to mismatch between the E/G ratio and the reticulocytic index. These individuals have an E/G ratio greater than 1, together with a low reticulocytic index typical of ineffective erythropoiesis in maturation disorders.
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Dorin, Merticaru