week 5: electronic cell counters instrumentation automation electric impedance coulter principle...
TRANSCRIPT
Week 5: Electronic Cell Counters
• Instrumentation
• Automation
• Electric impedance
• Coulter principle
• Optical scatter
• Myeloperoxidase
• Radio frequency probe
• Histogram
• Data plot
Instrumentation/Automation
• Increase productivity and precision
• Accuracy still depends on operator
• Other interventions• Calibration
• QC
• Maintenance
Brief History
• 1852: Hemocytometry by K Vierordt• 1956: Electronic impedance counter Coulter
Model A• 1970’s: Light scatter technique (e.g., Ortho
ELT-8• 1980’s: Cytochemical counter Technicon
H-6000; flowcytometry• 1990’s: VCS technology of Coulter STKS
Electrical Impedance
• Coulter principle first developed in 1950’s
R = k x Particle volume
Aperture size
Light Scatter
• Degree of light scatter is proportional to cell size
• Use of laminar flow using sheath fluid prevents cells from tumbling
• More precise cell grouping with size: differential count
Cytochemical
• Technicon measured the myeloperoxidase activity of leukocytes along with light scatter to differentiate leukocytes more precisely
• Development of flowcytometry: cell marker studies, DNA analysis, etc.
Radio Frequency Probe
• VCS (volume, conductivity, scatter) technology by Coulter
• Radio frequency probe with impedance by Sysmex
• Able to determine cell surface features and internal (nuclear, granular) complexity