Laboratory Evaluation of WBC's

Question 1

State the reference value for WBC count

Answer 1

4.5-11.5x10^3/cumm blood

Question 2

State the reference value for WBC differential

Answer 2

Seg-polys: 50-70%
Bands: 0-6%
Lymphs: 20-40%
Monos: 1-10%
Eos: 1-5%
Basos: 0-2%

Question 3

Describe “reversed differential”

Answer 3

Occurs in children, where their reference values of Lymphs and Polys are reversed

• Lymphs- 50-70%
• Polys- 20-40%

Question 4

Calculate the result of a manual white cell count

Answer 4

(#WBCs counted)x(dilution factor)x(volume factor)

WBCs)x(20)x(2.5

Question 5

Impedance principle based on the detection and measurement of changes in electrical resistance produced by a particle (cell) suspended in a conductive diluent… passing through a small aperture

Answer 5

“Coulter Principle”

Question 6

Number of pulses indicate:

Answer 6

Number of cells

-WBC, RBC, Platelet counts

Question 7

Size (amplitude) of the pulse indicates:

Answer 7

Cell volume

Question 8

Identify the three subpopulations of the WBC histogram

Answer 8

• Lymphocytes
• Mononuclear Cells
• Granulocytes

Question 9

Correcting WBC Count for nRBCs

Answer 9

• nRBCs not lysed with addition of diluting fluid falsely increases WBC count
• Guideline; if >5 nRBCs/100 WBCs
• Formula; (WBC*100)/(100+#nRBCs)

Question 10

Define WBC Histogram

Answer 10

Provides data for:

• Average particle size
• Distribution of particles about the mean size
• Presence of subpopulations