Automation

• What is the most commonly used methodology in CBC?

  Electronic resistance (impedance)
• How does the electronic resistance methodology utilize blood cells?

  It utilizes the non-conductive properties of blood cells
• What happens when a blood cell passes through the orifice of an aperture in impedance measurement?

  It displaces its own volume
• How are RBCs and platelets counted in the electronic resistance method?

  They are counted together and separated by pulse heights
• What is hydrodynamic focusing in the context of blood cell measurement?

  It forces cells to pass single file through the sensing zone
• What principle is the electronic resistance measurement based on?

  Coulter Principle
• What are the components measured in impedance and RF for blood cell analysis?

  3 parts (impedance) + RF (conductivity) = 5 parts
• What is the volume range for platelets?

  1. 20 fL
• What is the normal range for Mean Platelet Volume (MPV)?

  1. 8-10.2 fL
• What is the volume of red blood cells measured in fL?

  36 fL
• What is the volume range for lymphocytes?

  25-90 fL
• What is the volume range for mononuclear cells?

  90-160 fL
• What is the volume range for granulocytes?

  160-450 fL
• What happens if red cells are measured less than 35 fL?


  They will be falsely noted as red blood cells
• How does the size of cells affect volume measurement?

  Falsely increases or decreases in volume depends on the size
• Why are WBCs and hemoglobin counted together?

  Both need to lyse RBCs for easy visualization
• What is the effect of aperture diameter on volume measurement?

  It affects the measurement of red cells, platelets, and white cells
• How does protein build-up affect volume measurement?

  It decreases diameter and can falsely elevate volume
• What is the consequence of high cell volume due to protein build-up?

  It makes cell count lower due to clinging cells
• How can machines avoid protein build-up?

  They require regular clean-up and have self-cleaning ability
• What is cell carryover in automated machines?

  It can cause false or inaccurate results
• What is coincident passage loss?

  It refers to the orientation of the cell in the center of the aperture
• How does the deformability of RBCs affect measurement?

  It can influence the accuracy of the measurement
• What is the significance of recirculation of cells back into the sensing zone?

  It can lead to inaccurate results
• What does a flag/asterisk indicate in automated testing?

  It indicates an abnormal value obtained
• What does the RBC flag "RL" indicate?

  Low red blood cell count
• What does the RBC flag "RU" indicate?

  Higher or greater than the preset (macrocytic RBC)
• What does the WBC flag "R1" indicate?

  Abnormal; questionable; smaller lymphocytes
• What does the WBC flag "WL" indicate?

  Low WBC count (clumping)
• What does the WBC flag "WU" indicate?

  Severe leukocytosis
• What happens when RBCs with a nucleus are counted?

  They are counted as WBCs, falsely increasing WBC count
• What is ongoing research regarding the 6-part differential focused on?

  Detecting nucleated RBCs
• What is the normal platelet count range?

  1. 2-10.2
• What does the platelet flag "PL" indicate?

  Cell fragments smaller than platelets; lots of bacteria
• What does the platelet flag "PU" indicate?

  It could be due to clumping
• How does optical scatter work in blood analysis?

  A hydrodynamically focused sample stream is directed through a quartz flow cell past a focused light source
• What happens when cells pass through the focused beam of light in optical scatter?


  They are counted as they interrupt the beam of light
• What is the significance of diffraction in optical scatter?

  It refers to the bending of light around corners at small angles
• What does refraction refer to in the context of light?

  It is the bending of light due to change in speed
• What is reflection in optical scatter?

  It is when light rays turn back by obstruction using different angles