Hematopoiesis Application Exercise - Harrington

Question 1

What data are included in a CBC?

Answer 1

• Total counts:
  
  • WBC
  • RBC
  • PLT (platelet)
• Hb & Hct
• RBC indices:
  
  • MCV (mean corpuscular volume)
  • MCH (mean corpuscular Hb)
  • MCHC (mean corpuscular [Hb])
  • RDW (RBC distribution width)

Question 2

What do the following RBC indices represent and how do you calculate them?

1. MCV
2. MCH
3. MCHC

Answer 2

1. MCV = (Hct / #RBC) x 10
   
   • Average volume of an RBC
     
     • units of femtoliters
2. MCH = (Hb / #RBC) x 10
   
   • Average amount of Hb per RBC
     
     • units of picograms/cell
3. MCHC = (Hb / Hct) x 100
   
   • Average [Hb] per unit volume of RBCs
     
     • units of g/dL or mmol/L

Question 3

What does the RDW represent?

Answer 3

RBC distribution width: Measure of the variation of RBC volumes. Normal variation is 11.5-14.5% as per Wikipedia.

Note that this index measures variation in RBC volume, not diameter; “width” refers to the width of the distribution curve of RBC volumes.

Question 4

What data are included in a WBC differential?

Answer 4

• % Neutrophils
  
  • % Segs
  • % Bands
• % Monocytes
• % Eosinophils
• % Lymphocytes
• % Basophils
• Absolute counts
  
  • % cell type x total WBC count (from the CBC)

Question 5

Under what circumstances would an automated WBC differential analyzer flag a blood specimen for manual review by a technologist?

Answer 5

Presence of abnormal cells that that the instrument cannot categorize, e.g. immature WBCs (blasts).

Question 6

• What is the preffered method of scanning a peripheral blood smear?
• How many WBCs are tallied in a manual WBC differential?

Answer 6

• Scanning:
  
  1. Start in bottom left corner
  2. Move upwards until you reach the top left corner
  3. Move one field of vision to the right
  4. Move downwards until you reach the bottom
  5. Move one field of vision to the right
  6. Repeat 2-5 until finished
• 100 WBCs are counted

Question 7

(1 of 4) Identify the WBCs within the peripheral blood smear shown.

Answer 7

Question 8

(2 of 4) Identify the WBCs within the peripheral blood smear shown.

Answer 8

Question 9

(3 of 4) Identify the WBCs within the peripheral blood smear shown.

Answer 9

Question 10

(4 of 4) Identify the WBCs within the peripheral blood smear shown.

Answer 10