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