HEMA AUTOMATION

Electrical Impedence

Principle: Cells pass through an aperture with an electrical current flowing through simultaneously. Cells change the electrical resistance which is detected by voltage pulsed

Low-voltage direct current resistance

Electrical Impedence is AKA

# of cells

Number of pulses =__

Size of cell

Amplitude of pulses =__

Electrical Impedence

Type of automation that has three-part differential (lymphocytes, mononuclear cells, and granulocytes)

Hydrodynamic focusing

Electrical impedence uses ___ to reduce the chance of one cell being counted more than once (cell coincidence)

Light Scattering Optical method

Principle: uses a flow cytometer with a laser to measure light scattering properties of cells

Cell size

Forward angle light scatter measures ___

Cell granularity and lobulation

Side angle light scatter measures ___

Light Scattering Optical method

Type of automation with five part differential

Histogram

Utilizes impedance technology to represent cell number versus cell size

35 - 450 fL

Reference size range of WBC histogram

Lymphocytes

1st peak (35 - 90 fL)

Mononuclear cells (monocytes, reactive lymphocytes, immature WBC)

2nd peak (90-160 fL)

Granulocytes

3rd peak (160-450 fL)

nRBCs, giant platelets, or clumped plts

Abnormal WBC Histogram with population <35 fL

Reactive lymphocytes or blast cells

Abnormal WBC Histogram with peak overlap at 90 fL

Increase in bands, immature neutrophils, eosinophils, basophils

Abnormal WBC Histogram with peak overlap at 160 fL

High granulocyte count

Abnormal WBC Histogram with population >450 fL

Dimorphic erythrocyte population

Abnormal RBC Histogram with two peaks

Increased RDW (anisocytosis)

Abnormal RBC Histogram with Increased curve width

Macrocytic

Abnormal RBC Histogram with shift to the right

Microcytic

Abnormal RBC Histogram with Shift to the left

2-20 fL

Reference size range of platelets in histogram

Electrical interference

<2 fL platelets indicate __

Microcytic RBCs, schistocytes, giant platelets or clumped platelets

>20 fL platelets may indicate __

Scatterplots

A two dimensional representation of two or more cell properties plotted against each other

Fluidics

Optics

Electronics

Major components of a flow cytometer