heme unit 2.3

References values for WBC count and differential

Count:

• 4.5 - 11.5 ×10³/mm³

Differential:

• 50-70% segmented neutrophil

• 0-6% Bands

• 20-40% lymphocytes

• 1-10% monocytes

• 1-5% eosinophils

• 0-2% basophils

What are the reference values for children

Have revered differential

50-70% lymph’s

20-40% segs

Formula for manual WBC count

(Avg # cell x dilution x 10) / (length x width) ( # squares counted)

For easy way of finding total WBC count

Avg cell count x 50

Coulter principle

Method of counting cells and volumetric sizing based on the detection and measurement of charges in electrical resistance produced by a particle.

# of pulses = # of cells

Size (amplitude) of pulse = cell volume

Correcting WBC count

• nRBCs not lyses w/ addition of diluting fluid therefore falsely increased WBC count

• Formula:

  • (WBC x100) / ( 100 + nRBCs)

• Guideline

  • If more than 5 per 100 WBC than you correct

3 sub populations of WBC histogram

1. Lymphocytes

2. Mononuclear cells

3. Granulocytes

Histogram

Provide data on avg size and distribution of particles

Impedance principle

Detection and measurement of changes in electrical resistance produced by a particle suspended in a conductive diluent passing through a small aperture