HEMA LAB

• Why is it important to determine hemoglobin and hematocrit levels?

  It gives us an idea of the well-being of a patient.
• What does hemoglobin pertain to?

  It pertains to the state of oxygenation.
• What is the primary function of hemoglobin?

  To transport oxygen throughout the body.
• What does hematocrit measure?

  It measures the packed cell volume.
• What can hematocrit levels help determine?

  Whether the patient is anemic or not.
• Who identified hemoglobin and in what year?

  Felix Seyler in 1862.
• What is the principal purpose of hemoglobin?

  Oxygen delivery.
• What additional function does hemoglobin serve besides oxygen delivery?

  It pulls CO2 away from the tissues and maintains blood pH.
• What does the heme portion of hemoglobin contain?

  Four iron atoms in the ferrous state surrounded by protoporphyrin IX.
• What is the globin portion of hemoglobin made of?

  Amino acids linked together to form a polypeptide chain.
• What is the role of 2,3-diphosphoglycerate (2,3-DPG) in hemoglobin function?

  It diminishes the molecule’s affinity for oxygen.
• How does 2,3-DPG interact with deoxyhemoglobin?

  It combines with the beta chains and diminishes oxygen affinity.
• What happens to the beta chains of hemoglobin when oxygen is unloaded in tissues?

  The beta chains are pulled apart.
• What is oxyhemoglobin?

  Hemoglobin in a relaxed form that can bind with oxygen.
• What is deoxyhemoglobin?

  Hemoglobin in a tense state that cannot bind oxygen.
• What physiological conditions shift the oxygen dissociation curve to the right?

  • Anemia
  • Decreased pH (acidosis)
  • Increase in 2,3-DPG
• What conditions shift the oxygen dissociation curve to the left?

  • Decrease in 2,3-DPG
  • Higher body temperatures
  • Presence of abnormal hemoglobins or high oxygen affinity hemoglobin
  • Multiple transfusions of stored blood
  • Increased pH (alkalosis)
• What are the normal hemoglobin values for males?

  13.5 to 17.5 g/dL.
• What are the normal hemoglobin values for females?

  12.0 to 16.0 g/dL.
• Why are hemoglobin and hematocrit levels important for blood donation?

  They are preliminary tests to determine if the patient is suitable for donation.
• What are the two methods for hemoglobin determination?

  1. Acid Hematin Method
  2. Cyanmethemoglobin Method
• What is the principle of the Acid Hematin Method?

  Hemoglobin is converted to acid hematin with dilute 0.1 N HCl.
• What color is produced in the Acid Hematin Method?

  A brownish-yellow color.
• What is the principle of the Cyanmethemoglobin Method?

  Hemoglobin is converted from ferrous to ferric state to form methemoglobin.
• What is Drabkin's reagent used for in the Cyanmethemoglobin Method?

  It combines with methemoglobin to produce stable cyanmethemoglobin.
• What are the materials needed for the Acid Hematin Method?

  • Capillary or unclotted venous blood
  • Comparator block
  • Sahli pipette
  • Sahli graduated tube
  • Stirrer
  • Dropper
  • Distilled water
  • 0.1 N HCl
• What are the steps in the Acid Hematin Method procedure?

  1. Introduce 0.1 N HCl to the Sahli graduated tube.
  2. Draw blood with the Sahli pipette.
  3. Dispense blood into the graduated tube and mix.
  4. Allow to stand for 5 minutes.
  5. Add distilled water drop by drop and compare with the comparator block.
  6. Record the result when it matches the color standard.
• What are the steps in the Cyanmethemoglobin Method procedure?

  1. Place Drabkin’s reagent in a test tube.
  2. Draw blood with the Sahli pipette.
  3. Dispense blood into the test tube and mix.
  4. Cover and let it stand for 5 minutes.
  5. Transfer to a cuvette.
  6. Set spectrophotometer to 100% transmittance at 540 nm.
  7. Use cyanmethemoglobin reagent as a blank.
  8. Record the percentage transmittance.
• What are the normal hematocrit values for males?

  42% to 52%.
• What are the normal hematocrit values for females?

  37% to 47%.
• What is the packed cell volume (PCV)?

  It is the ratio of the volume occupied by RBCs to the volume of whole blood.
• How is the hematocrit percentage measured?

  By centrifuging a whole blood sample and measuring the ratio.
• What is the clinical use of PCV?

  To detect anemia, polycythemia, hemodilution, or hemoconcentration.
• What are the two types of hematocrit determination?

  1. Macromethod (Wintrobe Method)
  2. Micromethod (Microhematocrit)
• What is the procedure for the Macromethod of hematocrit determination?

  1. Mix the blood.
  2. Fill the Wintrobe tube to the 10 mark.
  3. Centrifuge for 30 minutes.
  4. Read the height of the PCV on the scale.
• What is the procedure for the Micromethod of hematocrit determination?

  1. Make a capillary puncture.
  2. Fill the capillary tube about 2/3 full.
  3. Seal one end with clay.
  4. Spin in a microhematocrit centrifuge for 5 minutes.
  5. Read the HCT using a microhematocrit reader.
• What are the sources of error in hematocrit determination?

  Increased:

  • Insufficient centrifugation
  • Improper sealing of capillary
  • Inclusion of buffy coat

  
  

  Decreased:

  • Prolonged centrifugation
  • Dehydration
  • Acute blood loss
• What does the erythrocyte sedimentation rate (ESR) measure?

  The rate of settling of RBCs in blood.
• What is the purpose of the ESR test?

  It is a non-specific measurement used to detect and monitor inflammation.
• What are the stages of the erythrocyte sedimentation rate?

  1. Aggregation Phase
  2. Sedimentation Phase
  3. Packaging Phase