1. Week 5: Electronic Cell Counters
Instrumentation
Automation
Electric impedance
Coulter principle
Optical scatter
Myeloperoxidase
Radio frequency probe
Histogram
Data plot

2. Instrumentation/Automation
Increase productivity and precision
Accuracy still depends on operator
Other interventions
Calibration QC
Maintenance

3. 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

4. Electrical Impedance Coulter principle first developed in 1950’s
R = k x Particle volume
Aperture size

6. Coulters A, F, ZBI

7. Coulters S and S-Plus

8. 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

9. Ortho ELT-8

11. 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.

14. Light Scatter and Myeloperoxidase Activity

15. 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

16. Sizing and Conductivity