Lesson 2-10

Principles of AutomatedHematology

History of Cell Counting

• 1855, hemacytometers• Manual counts until 1950s• Coulter

– Automated counter (1956)– Principle of electrical impedance– Early counters only performed RBC and WBC

counts

History of Cell Counting

• Today’s analyzers report >60 parameters

Two Basic Technologies

• Electrical-impedance counting• Light scatter

Two Basic Technologies• Electrical-impedance counting

– Electrolyte solution– Aperture, impedance– Improvements

Two Basic Technologies• Electrical-impedance counting

– Improvements– Examples

Two Basic Technologies• Light-scatter

– Laser [index of refraction]– Sheath-flow

Two Basic Technologies

• Light-scatter – Examples

RBC Parameters• RBC indices

– Mean cell volume [MCV]– Mean cell hemoglobin [MCH]– Mean cell hemoglobin concentration [MCHC]

RBC Parameters

• Relative RBC numbers plotted versus size

Automated Differential Counting

• Three-part

• Cytochemical staining• Image processing• Flow cytometry

Automated Differential Counting

Five-part differential

Automated Differential Counting

• Image processing

The End