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Once the product is tested and ready to be deployed it is released formally in the appropriate market. Sometimes product deployment happens in stages as per the business strategy of that organization. The product may first be released in a limited segment and tested in the real business environment (UAT- User acceptance testing).
Then based on the feedback, the product may be released as it is or with suggested enhancements in the targeting market segment. After the product is released in the market, its maintenance is done for the existing customer base.
Then based on the feedback, the product may be released as it is or with suggested enhancements in the targeting market segment. After the product is released in the market, its maintenance is done for the existing customer base.
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Vijaya

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Once the product is tested and ready to be deployed it is released ...
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DISCIPLINARY CONTENT
Monday, Nov 27, 2023
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DISCIPLINARY CONTENT
Today’s Health Problems and Health Education
THE HEALTH PROBLEMS OF greatest significance today are the chronic diseases. . . . The extent of chronic diseases, various disabling conditions, and the economic burden that they impose have been thoroughly documented. Health education and health educators will be expected to contribute to the reduction of the negative impact of such major health problems as heart disease, cancer, dental disease, mental illness and other neurological disturbances, obesity, accidents, and the adjustments necessary to a productive old age.
The new and unique role of health education in helping to meet these problems can perhaps be clarified through a review of some of the differences between procedures that have been successful in solving the problems of the acute communicable diseases and those that are available for coping with today’s problems.Youtube video link:YT embedded video:URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448258/Table:
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Special characters:Õ‡Numbering:
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The new and unique role of health education in helping to meet these problems can perhaps be clarified through a review of some of the differences between procedures that have been successful in solving the problems of the acute communicable diseases and those that are available for coping with today’s problems.Youtube video link:YT embedded video:URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448258/Table:
row 1
row 2
row 3
row 4
row 5
row 6
Special characters:Õ‡Numbering:
Test 1
Test 2
Bullets:
Test 3
Test 4
Authored by:
Vijayalaxmi mali

Posted on: #iteachmsu

Today’s Health Problems and Health Education
THE HEALTH PROBLEMS OF greatest significance today are the chr...
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DISCIPLINARY CONTENT
Thursday, Nov 23, 2023
Posted on: #iteachmsu
DISCIPLINARY CONTENT
Hemoglobin and Hematocrit
Hemoglobin (Hb) is the protein contained in red blood cells that is responsible for delivery of oxygen to the tissues. To ensure adequate tissue oxygenation, a sufficient hemoglobin level must be maintained. The amount of hemoglobin in whole blood is expressed in grams per deciliter (g/dl). The normal Hb level for males is 14 to 18 g/dl; that for females is 12 to 16 g/dl. When the hemoglobin level is low, the patient has anemia. An erythrocytosis is the consequence of too many red cells; this results in hemoglobin levels above normal.
The hematocrit measures the volume of red blood cells compared to the total blood volume (red blood cells and plasma). The normal hematocrit for men is 40 to 54%; for women it is 36 to 48%. This value can be determined directly by microhematocrit centrifugation or calculated indirectly. Automated cell counters calculate the hematocrit by multiplying the red cell number (in millions/mm3) by the mean cell volume (MCV, in femtoliters). When so assayed, it is subject to the vagaries inherent in obtaining an accurate measurement of the MCV (see Chapter 152).
Both the hemoglobin and the hematocrit are based on whole blood and are therefore dependent on plasma volume. If a patient is severely dehydrated, the hemoglobin and hematocrit will appear higher than if the patient were normovolemic; if the patient is fluid overloaded, they will be lower than their actual level. To assess true red cell mass, independent radionuclide evaluation of the red cells and plasma (by 51Cr and 131I respectively) must be performed.
Go to:
Technique
Hematocrit
If the hematocrit must be determined quickly, as is often the case when a patient hemorrhages, it may be necessary to measure the hematocrit directly without the use of an automated counter. The materials needed are:
Lancets
Alcohol prep pads
Gauze pads
Microhematocrit tubes (heparinized)
Sealant ("Seal-Ease," "Crit-Seal," etc)
Microhematocrit centrifuge
Microhematocrit reader
If venipuncture is required: tourniquet, syringe, tube containing anticoagulant (EDTA, citrate)
For hematocrits obtained by fingerstick, wipe the fingertip pad of the fourth finger of the nondominant hand with the alcohol prep pad. Make certain the area is allowed to dry. Prick the fingertip with the lancet. Place the hematocrit tube near the incision site and allow the blood to flow via capillary action into the hematocrit tube until it is two-thirds to three-fourths full or to a predesignated mark on the tube. Avoid "milking" the finger if possible; this causes the expression of tissue fluids and may result in a falsely low hematocrit. Always fill at least three tubes. For hematocrits obtained by venipuncture, draw a sample of blood into the tube containing anticoagulant and mix well. Dip the hematocrit tube into the blood and allow the blood to rise to the desired two-thirds to three-quarters level. Because blood cells naturally sediment, a prior thorough mixing of the blood in the tube is necessary to ensure accurate reading.
After cleaning the outside of the hematocrit tubes of excess blood, invert the tube slowly so that the blood migrates just short of the bottom end of the tube. Seal the bottom of the tube with sealant. Make certain that little or no air is interspersed in the column of blood. If the seal is incomplete, leakage will occur during centrifugation and false readings will be obtained.
Place the tubes in a microhematocrit centrifuge and spin for 3 to 5 minutes at high speed. A shorter spin will not allow for complete sedimentation.
Using either a hematocrit reader or any ruled apparatus, measure the length of the column of the packed red cells and divide it by the length of the whole column of blood (cells and plasma), as in Figure 151.1. To obtain the hematocrit, multiply this number by 100%. Average all readings obtained from the different microhematocrit tubes.
Figure 151.1
Microhematocrit tube after sedimentation. The hematocrit is a ratio of the packed cells to total volume.
Example: If the column of packed red cells measures 20 mm and the whole blood column measures 50 mm, the hematocrit is 20/50 = 0.4 or (0.4 × 100%) = 40%.
Hemoglobin
Hemoglobin determinations will usually be performed by an automated cell counter from a tube of well-mixed EDTA-anticoagulated blood filled to a predetermined level. In this assay, all forms of hemoglobins are converted to the colored protein cyanomethemoglobin and measured by a colorimeter. An inadequate sample, whether due to insufficient volume or inadequate anticoagulation, may give false readings. If it is necessary to determine the level of anemia quickly, the hematocrit is an easier, more convenient test.
Hemoglobin Electrophoresis
Hemoglobin electrophoresis measures the mobility of hemoglobin in an electric field; it can therefore detect only those abnormalities in hemoglobin that alter the charge. Electrophoretic mobilities are affected by pH and by the medium in which the test is conducted. Screening tests typically use a hemolysate of anticoagulated blood electrophoresed on cellulose acetate at pH 8.6 to 8.8. If necessary, a further electrophoresis in starch gel at pH 6.2 to 6.8 is performed. At that stage, the work will usually be performed by a specialized laboratory.
Hemoglobin electrophoresis will not readily assess situations where there are neutral amino acid substitutions or where the hemoglobin is normal but the constituent chains are not produced in equal numbers (thalassemias). The diagnosis of alpha thalassemia of a mild to moderate degree cannot be made by hemoglobin electrophoresis; the diagnosis of beta thalassemia may be made by inference from an increase in the Hb A2.
A standard electrophoresis would look like Figure 151.2.
Figure 151.2
A standard hemoglobin electrophoresis (cellulose acetate, pH 8.6).
Go to:
Basic Science
The molecular weight of hemoglobin is approximately 64,500 daltons. Hb is composed of two pairs of dissimilar chains, α and β, each defined by a specific amino acid sequence and incorporating an iron-containing heme group. Two α–β dimers combine to form a hemoglobin tetramer. This allows for the "heme–heme" interaction necessary for effective oxygen uptake (deoxyhemoglobin → oxyhemoglobin) and delivery (oxyhemoglobin → deoxyhemoglobin). The oxygen affinity of hemoglobin is a function of this heme–heme interaction and of pH (Bohr effect), and is a measure of how many hemoglobin molecules have oxygen bound to them for a given level of oxygen tension. In a normal individual the major hemoglobin is Hb A, constituting approximately 97% of the total hemoglobin. Variations and/or amino acid substitutions in these chains exist. Some are deleterious to the normal function of hemoglobin, whereas others may have relatively normal oxygen affinity and stability. Hemoglobins containing different types of chains make up the remainder of the hemoglobin content in red cells (α2δ2 = Hb A2 approximately 2%; α2γ2 = Hb F approximately 1%).
Substitutions in the normal hemoglobin amino acid sequence may result in hemoglobins that have different sub-unit interactions and varying affinities for oxygen. For example, a substitution of the sixth amino acid on the beta chain causes Hb S, or sickle hemoglobin. Hb S has a lower oxygen affinity and surrenders its oxygen more readily. Hb F, a normal minor hemoglobin constituent, has a higher oxygen affinity.
If the oxygen dissociation curve is abnormal, the body will adjust the hemoglobin level to ensure adequate oxygen distribution to the tissues. Thus in a rare disease like hemoglobin Hotel Dieu, the difficulty in extracting oxygen from a variant hemoglobin with increased oxygen affinity could result in a lack of oxygen for the tissues (tissue hypoxia) and a compensatory erythrocytosis. The smaller fraction of oxygen released from the hemoglobin is thereby offset by the increased number of hemoglobin molecules. Similarly, in sickle cell anemia, the decreased oxygen affinity allows these patients more tissue oxygen at any given hemoglobin level.Testing.
The hematocrit measures the volume of red blood cells compared to the total blood volume (red blood cells and plasma). The normal hematocrit for men is 40 to 54%; for women it is 36 to 48%. This value can be determined directly by microhematocrit centrifugation or calculated indirectly. Automated cell counters calculate the hematocrit by multiplying the red cell number (in millions/mm3) by the mean cell volume (MCV, in femtoliters). When so assayed, it is subject to the vagaries inherent in obtaining an accurate measurement of the MCV (see Chapter 152).
Both the hemoglobin and the hematocrit are based on whole blood and are therefore dependent on plasma volume. If a patient is severely dehydrated, the hemoglobin and hematocrit will appear higher than if the patient were normovolemic; if the patient is fluid overloaded, they will be lower than their actual level. To assess true red cell mass, independent radionuclide evaluation of the red cells and plasma (by 51Cr and 131I respectively) must be performed.
Go to:
Technique
Hematocrit
If the hematocrit must be determined quickly, as is often the case when a patient hemorrhages, it may be necessary to measure the hematocrit directly without the use of an automated counter. The materials needed are:
Lancets
Alcohol prep pads
Gauze pads
Microhematocrit tubes (heparinized)
Sealant ("Seal-Ease," "Crit-Seal," etc)
Microhematocrit centrifuge
Microhematocrit reader
If venipuncture is required: tourniquet, syringe, tube containing anticoagulant (EDTA, citrate)
For hematocrits obtained by fingerstick, wipe the fingertip pad of the fourth finger of the nondominant hand with the alcohol prep pad. Make certain the area is allowed to dry. Prick the fingertip with the lancet. Place the hematocrit tube near the incision site and allow the blood to flow via capillary action into the hematocrit tube until it is two-thirds to three-fourths full or to a predesignated mark on the tube. Avoid "milking" the finger if possible; this causes the expression of tissue fluids and may result in a falsely low hematocrit. Always fill at least three tubes. For hematocrits obtained by venipuncture, draw a sample of blood into the tube containing anticoagulant and mix well. Dip the hematocrit tube into the blood and allow the blood to rise to the desired two-thirds to three-quarters level. Because blood cells naturally sediment, a prior thorough mixing of the blood in the tube is necessary to ensure accurate reading.
After cleaning the outside of the hematocrit tubes of excess blood, invert the tube slowly so that the blood migrates just short of the bottom end of the tube. Seal the bottom of the tube with sealant. Make certain that little or no air is interspersed in the column of blood. If the seal is incomplete, leakage will occur during centrifugation and false readings will be obtained.
Place the tubes in a microhematocrit centrifuge and spin for 3 to 5 minutes at high speed. A shorter spin will not allow for complete sedimentation.
Using either a hematocrit reader or any ruled apparatus, measure the length of the column of the packed red cells and divide it by the length of the whole column of blood (cells and plasma), as in Figure 151.1. To obtain the hematocrit, multiply this number by 100%. Average all readings obtained from the different microhematocrit tubes.
Figure 151.1
Microhematocrit tube after sedimentation. The hematocrit is a ratio of the packed cells to total volume.
Example: If the column of packed red cells measures 20 mm and the whole blood column measures 50 mm, the hematocrit is 20/50 = 0.4 or (0.4 × 100%) = 40%.
Hemoglobin
Hemoglobin determinations will usually be performed by an automated cell counter from a tube of well-mixed EDTA-anticoagulated blood filled to a predetermined level. In this assay, all forms of hemoglobins are converted to the colored protein cyanomethemoglobin and measured by a colorimeter. An inadequate sample, whether due to insufficient volume or inadequate anticoagulation, may give false readings. If it is necessary to determine the level of anemia quickly, the hematocrit is an easier, more convenient test.
Hemoglobin Electrophoresis
Hemoglobin electrophoresis measures the mobility of hemoglobin in an electric field; it can therefore detect only those abnormalities in hemoglobin that alter the charge. Electrophoretic mobilities are affected by pH and by the medium in which the test is conducted. Screening tests typically use a hemolysate of anticoagulated blood electrophoresed on cellulose acetate at pH 8.6 to 8.8. If necessary, a further electrophoresis in starch gel at pH 6.2 to 6.8 is performed. At that stage, the work will usually be performed by a specialized laboratory.
Hemoglobin electrophoresis will not readily assess situations where there are neutral amino acid substitutions or where the hemoglobin is normal but the constituent chains are not produced in equal numbers (thalassemias). The diagnosis of alpha thalassemia of a mild to moderate degree cannot be made by hemoglobin electrophoresis; the diagnosis of beta thalassemia may be made by inference from an increase in the Hb A2.
A standard electrophoresis would look like Figure 151.2.
Figure 151.2
A standard hemoglobin electrophoresis (cellulose acetate, pH 8.6).
Go to:
Basic Science
The molecular weight of hemoglobin is approximately 64,500 daltons. Hb is composed of two pairs of dissimilar chains, α and β, each defined by a specific amino acid sequence and incorporating an iron-containing heme group. Two α–β dimers combine to form a hemoglobin tetramer. This allows for the "heme–heme" interaction necessary for effective oxygen uptake (deoxyhemoglobin → oxyhemoglobin) and delivery (oxyhemoglobin → deoxyhemoglobin). The oxygen affinity of hemoglobin is a function of this heme–heme interaction and of pH (Bohr effect), and is a measure of how many hemoglobin molecules have oxygen bound to them for a given level of oxygen tension. In a normal individual the major hemoglobin is Hb A, constituting approximately 97% of the total hemoglobin. Variations and/or amino acid substitutions in these chains exist. Some are deleterious to the normal function of hemoglobin, whereas others may have relatively normal oxygen affinity and stability. Hemoglobins containing different types of chains make up the remainder of the hemoglobin content in red cells (α2δ2 = Hb A2 approximately 2%; α2γ2 = Hb F approximately 1%).
Substitutions in the normal hemoglobin amino acid sequence may result in hemoglobins that have different sub-unit interactions and varying affinities for oxygen. For example, a substitution of the sixth amino acid on the beta chain causes Hb S, or sickle hemoglobin. Hb S has a lower oxygen affinity and surrenders its oxygen more readily. Hb F, a normal minor hemoglobin constituent, has a higher oxygen affinity.
If the oxygen dissociation curve is abnormal, the body will adjust the hemoglobin level to ensure adequate oxygen distribution to the tissues. Thus in a rare disease like hemoglobin Hotel Dieu, the difficulty in extracting oxygen from a variant hemoglobin with increased oxygen affinity could result in a lack of oxygen for the tissues (tissue hypoxia) and a compensatory erythrocytosis. The smaller fraction of oxygen released from the hemoglobin is thereby offset by the increased number of hemoglobin molecules. Similarly, in sickle cell anemia, the decreased oxygen affinity allows these patients more tissue oxygen at any given hemoglobin level.Testing.
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Blood count

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Hemoglobin and Hematocrit
Hemoglobin (Hb) is the protein contained in red blood cells th...
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DISCIPLINARY CONTENT
Friday, Oct 20, 2023
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DISCIPLINARY CONTENT
Hemoglobin and Hematocrit
Hemoglobin (Hb) is the protein contained in red blood cells that is responsible for delivery of oxygen to the tissues. To ensure adequate tissue oxygenation, a sufficient hemoglobin level must be maintained. The amount of hemoglobin in whole blood is expressed in grams per deciliter (g/dl). The normal Hb level for males is 14 to 18 g/dl; that for females is 12 to 16 g/dl. When the hemoglobin level is low, the patient has anemia. An erythrocytosis is the consequence of too many red cells; this results in hemoglobin levels above normal.
The hematocrit measures the volume of red blood cells compared to the total blood volume (red blood cells and plasma). The normal hematocrit for men is 40 to 54%; for women it is 36 to 48%. This value can be determined directly by microhematocrit centrifugation or calculated indirectly. Automated cell counters calculate the hematocrit by multiplying the red cell number (in millions/mm3) by the mean cell volume (MCV, in femtoliters). When so assayed, it is subject to the vagaries inherent in obtaining an accurate measurement of the MCV (see Chapter 152).
Both the hemoglobin and the hematocrit are based on whole blood and are therefore dependent on plasma volume. If a patient is severely dehydrated, the hemoglobin and hematocrit will appear higher than if the patient were normovolemic; if the patient is fluid overloaded, they will be lower than their actual level. To assess true red cell mass, independent radionuclide evaluation of the red cells and plasma (by 51Cr and 131I respectively) must be performed.
Go to:
Technique
Hematocrit
If the hematocrit must be determined quickly, as is often the case when a patient hemorrhages, it may be necessary to measure the hematocrit directly without the use of an automated counter. The materials needed are:
Lancets
Alcohol prep pads
Gauze pads
Microhematocrit tubes (heparinized)
Sealant ("Seal-Ease," "Crit-Seal," etc)
Microhematocrit centrifuge
Microhematocrit reader
If venipuncture is required: tourniquet, syringe, tube containing anticoagulant (EDTA, citrate)
For hematocrits obtained by fingerstick, wipe the fingertip pad of the fourth finger of the nondominant hand with the alcohol prep pad. Make certain the area is allowed to dry. Prick the fingertip with the lancet. Place the hematocrit tube near the incision site and allow the blood to flow via capillary action into the hematocrit tube until it is two-thirds to three-fourths full or to a predesignated mark on the tube. Avoid "milking" the finger if possible; this causes the expression of tissue fluids and may result in a falsely low hematocrit. Always fill at least three tubes. For hematocrits obtained by venipuncture, draw a sample of blood into the tube containing anticoagulant and mix well. Dip the hematocrit tube into the blood and allow the blood to rise to the desired two-thirds to three-quarters level. Because blood cells naturally sediment, a prior thorough mixing of the blood in the tube is necessary to ensure accurate reading.
After cleaning the outside of the hematocrit tubes of excess blood, invert the tube slowly so that the blood migrates just short of the bottom end of the tube. Seal the bottom of the tube with sealant. Make certain that little or no air is interspersed in the column of blood. If the seal is incomplete, leakage will occur during centrifugation and false readings will be obtained.
Place the tubes in a microhematocrit centrifuge and spin for 3 to 5 minutes at high speed. A shorter spin will not allow for complete sedimentation.
Using either a hematocrit reader or any ruled apparatus, measure the length of the column of the packed red cells and divide it by the length of the whole column of blood (cells and plasma), as in Figure 151.1. To obtain the hematocrit, multiply this number by 100%. Average all readings obtained from the different microhematocrit tubes.
Figure 151.1
Microhematocrit tube after sedimentation. The hematocrit is a ratio of the packed cells to total volume.
Example: If the column of packed red cells measures 20 mm and the whole blood column measures 50 mm, the hematocrit is 20/50 = 0.4 or (0.4 × 100%) = 40%.
Hemoglobin
Hemoglobin determinations will usually be performed by an automated cell counter from a tube of well-mixed EDTA-anticoagulated blood filled to a predetermined level. In this assay, all forms of hemoglobins are converted to the colored protein cyanomethemoglobin and measured by a colorimeter. An inadequate sample, whether due to insufficient volume or inadequate anticoagulation, may give false readings. If it is necessary to determine the level of anemia quickly, the hematocrit is an easier, more convenient test.
Hemoglobin Electrophoresis
Hemoglobin electrophoresis measures the mobility of hemoglobin in an electric field; it can therefore detect only those abnormalities in hemoglobin that alter the charge. Electrophoretic mobilities are affected by pH and by the medium in which the test is conducted. Screening tests typically use a hemolysate of anticoagulated blood electrophoresed on cellulose acetate at pH 8.6 to 8.8. If necessary, a further electrophoresis in starch gel at pH 6.2 to 6.8 is performed. At that stage, the work will usually be performed by a specialized laboratory.
Hemoglobin electrophoresis will not readily assess situations where there are neutral amino acid substitutions or where the hemoglobin is normal but the constituent chains are not produced in equal numbers (thalassemias). The diagnosis of alpha thalassemia of a mild to moderate degree cannot be made by hemoglobin electrophoresis; the diagnosis of beta thalassemia may be made by inference from an increase in the Hb A2.
A standard electrophoresis would look like Figure 151.2.
Figure 151.2
A standard hemoglobin electrophoresis (cellulose acetate, pH 8.6).
Go to:
Basic Science
The molecular weight of hemoglobin is approximately 64,500 daltons. Hb is composed of two pairs of dissimilar chains, α and β, each defined by a specific amino acid sequence and incorporating an iron-containing heme group. Two α–β dimers combine to form a hemoglobin tetramer. This allows for the "heme–heme" interaction necessary for effective oxygen uptake (deoxyhemoglobin → oxyhemoglobin) and delivery (oxyhemoglobin → deoxyhemoglobin). The oxygen affinity of hemoglobin is a function of this heme–heme interaction and of pH (Bohr effect), and is a measure of how many hemoglobin molecules have oxygen bound to them for a given level of oxygen tension. In a normal individual the major hemoglobin is Hb A, constituting approximately 97% of the total hemoglobin. Variations and/or amino acid substitutions in these chains exist. Some are deleterious to the normal function of hemoglobin, whereas others may have relatively normal oxygen affinity and stability. Hemoglobins containing different types of chains make up the remainder of the hemoglobin content in red cells (α2δ2 = Hb A2 approximately 2%; α2γ2 = Hb F approximately 1%).
Substitutions in the normal hemoglobin amino acid sequence may result in hemoglobins that have different sub-unit interactions and varying affinities for oxygen. For example, a substitution of the sixth amino acid on the beta chain causes Hb S, or sickle hemoglobin. Hb S has a lower oxygen affinity and surrenders its oxygen more readily. Hb F, a normal minor hemoglobin constituent, has a higher oxygen affinity.
If the oxygen dissociation curve is abnormal, the body will adjust the hemoglobin level to ensure adequate oxygen distribution to the tissues. Thus in a rare disease like hemoglobin Hotel Dieu, the difficulty in extracting oxygen from a variant hemoglobin with increased oxygen affinity could result in a lack of oxygen for the tissues (tissue hypoxia) and a compensatory erythrocytosis. The smaller fraction of oxygen released from the hemoglobin is thereby offset by the increased number of hemoglobin molecules. Similarly, in sickle cell anemia, the decreased oxygen affinity allows these patients more tissue oxygen at any given hemoglobin level.Testing.
The hematocrit measures the volume of red blood cells compared to the total blood volume (red blood cells and plasma). The normal hematocrit for men is 40 to 54%; for women it is 36 to 48%. This value can be determined directly by microhematocrit centrifugation or calculated indirectly. Automated cell counters calculate the hematocrit by multiplying the red cell number (in millions/mm3) by the mean cell volume (MCV, in femtoliters). When so assayed, it is subject to the vagaries inherent in obtaining an accurate measurement of the MCV (see Chapter 152).
Both the hemoglobin and the hematocrit are based on whole blood and are therefore dependent on plasma volume. If a patient is severely dehydrated, the hemoglobin and hematocrit will appear higher than if the patient were normovolemic; if the patient is fluid overloaded, they will be lower than their actual level. To assess true red cell mass, independent radionuclide evaluation of the red cells and plasma (by 51Cr and 131I respectively) must be performed.
Go to:
Technique
Hematocrit
If the hematocrit must be determined quickly, as is often the case when a patient hemorrhages, it may be necessary to measure the hematocrit directly without the use of an automated counter. The materials needed are:
Lancets
Alcohol prep pads
Gauze pads
Microhematocrit tubes (heparinized)
Sealant ("Seal-Ease," "Crit-Seal," etc)
Microhematocrit centrifuge
Microhematocrit reader
If venipuncture is required: tourniquet, syringe, tube containing anticoagulant (EDTA, citrate)
For hematocrits obtained by fingerstick, wipe the fingertip pad of the fourth finger of the nondominant hand with the alcohol prep pad. Make certain the area is allowed to dry. Prick the fingertip with the lancet. Place the hematocrit tube near the incision site and allow the blood to flow via capillary action into the hematocrit tube until it is two-thirds to three-fourths full or to a predesignated mark on the tube. Avoid "milking" the finger if possible; this causes the expression of tissue fluids and may result in a falsely low hematocrit. Always fill at least three tubes. For hematocrits obtained by venipuncture, draw a sample of blood into the tube containing anticoagulant and mix well. Dip the hematocrit tube into the blood and allow the blood to rise to the desired two-thirds to three-quarters level. Because blood cells naturally sediment, a prior thorough mixing of the blood in the tube is necessary to ensure accurate reading.
After cleaning the outside of the hematocrit tubes of excess blood, invert the tube slowly so that the blood migrates just short of the bottom end of the tube. Seal the bottom of the tube with sealant. Make certain that little or no air is interspersed in the column of blood. If the seal is incomplete, leakage will occur during centrifugation and false readings will be obtained.
Place the tubes in a microhematocrit centrifuge and spin for 3 to 5 minutes at high speed. A shorter spin will not allow for complete sedimentation.
Using either a hematocrit reader or any ruled apparatus, measure the length of the column of the packed red cells and divide it by the length of the whole column of blood (cells and plasma), as in Figure 151.1. To obtain the hematocrit, multiply this number by 100%. Average all readings obtained from the different microhematocrit tubes.
Figure 151.1
Microhematocrit tube after sedimentation. The hematocrit is a ratio of the packed cells to total volume.
Example: If the column of packed red cells measures 20 mm and the whole blood column measures 50 mm, the hematocrit is 20/50 = 0.4 or (0.4 × 100%) = 40%.
Hemoglobin
Hemoglobin determinations will usually be performed by an automated cell counter from a tube of well-mixed EDTA-anticoagulated blood filled to a predetermined level. In this assay, all forms of hemoglobins are converted to the colored protein cyanomethemoglobin and measured by a colorimeter. An inadequate sample, whether due to insufficient volume or inadequate anticoagulation, may give false readings. If it is necessary to determine the level of anemia quickly, the hematocrit is an easier, more convenient test.
Hemoglobin Electrophoresis
Hemoglobin electrophoresis measures the mobility of hemoglobin in an electric field; it can therefore detect only those abnormalities in hemoglobin that alter the charge. Electrophoretic mobilities are affected by pH and by the medium in which the test is conducted. Screening tests typically use a hemolysate of anticoagulated blood electrophoresed on cellulose acetate at pH 8.6 to 8.8. If necessary, a further electrophoresis in starch gel at pH 6.2 to 6.8 is performed. At that stage, the work will usually be performed by a specialized laboratory.
Hemoglobin electrophoresis will not readily assess situations where there are neutral amino acid substitutions or where the hemoglobin is normal but the constituent chains are not produced in equal numbers (thalassemias). The diagnosis of alpha thalassemia of a mild to moderate degree cannot be made by hemoglobin electrophoresis; the diagnosis of beta thalassemia may be made by inference from an increase in the Hb A2.
A standard electrophoresis would look like Figure 151.2.
Figure 151.2
A standard hemoglobin electrophoresis (cellulose acetate, pH 8.6).
Go to:
Basic Science
The molecular weight of hemoglobin is approximately 64,500 daltons. Hb is composed of two pairs of dissimilar chains, α and β, each defined by a specific amino acid sequence and incorporating an iron-containing heme group. Two α–β dimers combine to form a hemoglobin tetramer. This allows for the "heme–heme" interaction necessary for effective oxygen uptake (deoxyhemoglobin → oxyhemoglobin) and delivery (oxyhemoglobin → deoxyhemoglobin). The oxygen affinity of hemoglobin is a function of this heme–heme interaction and of pH (Bohr effect), and is a measure of how many hemoglobin molecules have oxygen bound to them for a given level of oxygen tension. In a normal individual the major hemoglobin is Hb A, constituting approximately 97% of the total hemoglobin. Variations and/or amino acid substitutions in these chains exist. Some are deleterious to the normal function of hemoglobin, whereas others may have relatively normal oxygen affinity and stability. Hemoglobins containing different types of chains make up the remainder of the hemoglobin content in red cells (α2δ2 = Hb A2 approximately 2%; α2γ2 = Hb F approximately 1%).
Substitutions in the normal hemoglobin amino acid sequence may result in hemoglobins that have different sub-unit interactions and varying affinities for oxygen. For example, a substitution of the sixth amino acid on the beta chain causes Hb S, or sickle hemoglobin. Hb S has a lower oxygen affinity and surrenders its oxygen more readily. Hb F, a normal minor hemoglobin constituent, has a higher oxygen affinity.
If the oxygen dissociation curve is abnormal, the body will adjust the hemoglobin level to ensure adequate oxygen distribution to the tissues. Thus in a rare disease like hemoglobin Hotel Dieu, the difficulty in extracting oxygen from a variant hemoglobin with increased oxygen affinity could result in a lack of oxygen for the tissues (tissue hypoxia) and a compensatory erythrocytosis. The smaller fraction of oxygen released from the hemoglobin is thereby offset by the increased number of hemoglobin molecules. Similarly, in sickle cell anemia, the decreased oxygen affinity allows these patients more tissue oxygen at any given hemoglobin level.Testing.
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Blood count
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Hemoglobin and Hematocrit
Hemoglobin (Hb) is the protein contained in red blood cells th...
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DISCIPLINARY CONTENT
Friday, Oct 20, 2023
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Cooperative Learning
Cooperative LearningCarefully structured cooperative learning groups in which each student is assigned a role and has clear expectations for desired outcomes are very helpful for students with ADHD. The more structured the cooperative activity, the more likely it is that these students will succeed.Sharing Strategies Think, Pair, Share/Square Share/Group Share: Using thisapproach, students work with peer partners to discuss the lesson, check each other’swork, and share strategies.Partner Reading Student partners take turns reading orally and listening to each other. Peer partners can also be helpful with discussing answers to comprehension questions, spelling, proofreading, and solving
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Hezon Burg Jamesa

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Cooperative Learning
Cooperative LearningCarefully structured cooperative learning group...
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Thursday, Oct 19, 2023
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Culture of Collaboration
Number of Directions: Give a minimal number of directions or steps at a time.If necessary, have students repeat the directions to the teacher or a peer partner.
Form of Directions: Provide written directions or steps, or a visual model of acompleted project. Teach students how to refer to these items as reminders ofprocess steps to complete tasks. This strategy is particularly helpful for long-termprojects.
Written AssignmentsMany students with ADHD have particular challenges with written work due to finemotorskills difficulties, motor planning issues, and difficulty alternating their attentionfrom a book to their written responses.
Students with ADHD may also need assistance breaking a larger task or project into smaller, more workable units.
The following strategies can be used to address these needs.
Deconstructing Tasks: Break tasks into smaller units.o Limit the amount of work per page.o Cover up part of the work on a page.o Allow extra time for completing tasks.o Provide work breaks.o Allow students to use a computer to type or to use speech-to-text software.o Reduce the length of written assignments.
Limit the amount of work per page.
Cover up part of the work on a page.
Allow extra time for completing tasks.
Provide work breaks.
Allow students to use a computer to type or to use speech-to-text software
Reduce the length of written assignments.
Form of Directions: Provide written directions or steps, or a visual model of acompleted project. Teach students how to refer to these items as reminders ofprocess steps to complete tasks. This strategy is particularly helpful for long-termprojects.
Written AssignmentsMany students with ADHD have particular challenges with written work due to finemotorskills difficulties, motor planning issues, and difficulty alternating their attentionfrom a book to their written responses.
Students with ADHD may also need assistance breaking a larger task or project into smaller, more workable units.
The following strategies can be used to address these needs.
Deconstructing Tasks: Break tasks into smaller units.o Limit the amount of work per page.o Cover up part of the work on a page.o Allow extra time for completing tasks.o Provide work breaks.o Allow students to use a computer to type or to use speech-to-text software.o Reduce the length of written assignments.
Limit the amount of work per page.
Cover up part of the work on a page.
Allow extra time for completing tasks.
Provide work breaks.
Allow students to use a computer to type or to use speech-to-text software
Reduce the length of written assignments.
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Culture of Collaboration
Number of Directions: Give a minimal number of directions or steps ...
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DISCIPLINARY CONTENT
Tuesday, Oct 17, 2023
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DISCIPLINARY CONTENT
Set an achievable deadline
Establishing deadlines can help your team members complete their assigned tasks before the project's due date. Doing this can keep them engaged and productive. You can also set multiple team deadlines before the final project deadline to keep team members accountable. Consider using a time tracker app and time management techniques. Doing this can help you understand how everyone works to meet deadlines.
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Set an achievable deadline
Establishing deadlines can help your team members complete their as...
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DISCIPLINARY CONTENT
Friday, Oct 13, 2023
Posted on: Engineering
DISCIPLINARY CONTENT
Culture of Collaboration & Interprofessional Teaming
This program is an online continuous course with no specific start or end date. Creating a Culture of Collaboration and Interprofessional Teaming is an online self-paced course offering. This offering is made possible through the support of Venturit's internal WIzdn team.
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Venturit Super Admin

Posted on: Engineering

Culture of Collaboration & Interprofessional Teaming
This program is an online continuous course with no specific start ...
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DISCIPLINARY CONTENT
Wednesday, Aug 16, 2023