Element HT5^®

Best-in-Class Technology

3 Measurement Methods Used:

• Electrical Impedance method for determining the RBC and PLT data
• Colorimetric Method for determining the HGB
• Flow Cytometry by Laser for determining the WBC data
• Other parameter results are obtained via calculation

1. Electrical Impedance Method

RBCs/PLTs are counted and sized by the Electrical Impedance method. This method is based on the measurement of changes in electrical resistance produced by a particle, which in this case is a blood cell, suspended in a conductive diluent as it passes through an aperture of known dimensions. A pair of electrodes is submerged in the liquid on both sides of the aperture to create an electrical pathway. As each particle passes through the aperture, a transitory change in the resistance between the electrodes is produced. This change produces a measurable electrical pulse. The number of pulses generated represents the number of particles that passed through the aperture. The amplitude of each pulse is proportional to the volume of each particle.

Output includes numeric values, percentages plus histograms for RBC, WBC & PLT plus scatter plots for analyzing cell volume, complexity and granularity.

2. Flow Cytometry by Laser

After a predetermined volume of blood is aspirated and diluted by a certain amount of reagent, it is injected into the flow cell. Surrounded with sheath fluid (diluent), the blood cells pass through the center of the flow cell in a single column at a faster speed. When the blood cells suspended in the diluent pass through the flow cell, they are exposed to a laser beam.

The intensity of scatter light reflects the blood cell size and intracellular density. The low-angle scattered light reflects cell size, and the high-angle scattered light reflects intracellular density (nucleus size and density). The optical detector receives this scatter light and converts it into electrical pulses. Pulse data collected can be used to draw a 3-dimensional distribution (scattergram).

Triple angle scatter detects cell volume, complexity and granularity of cells.

• Low Angle Scatter (LAS)-Detects Cell Volume
• Mid Angle Scatter (MAS)- Detects Cellular Complexity
• Wide Angle Scatter (WAS)-Detects Cellular Granularity
• Multiple angle scatterplots aid to differentiate WBC differential

3. Colorimetric Method

The WBC/HGB dilution is delivered to the HGB bath where it is bubble mixed with a certain amount of lyse, which converts hemoglobin to a hemoglobin complex that is measurable at 530 nm. An LED is mounted on one side of the bath and emits a beam of monochromatic light, whose central wavelength is 530 nm. The light passes through the sample and is then measured by an optical sensor that is mounted on the opposite side. The signal is then amplified and the voltage is measured and compared to the blank reference reading (readings taken when there is only diluent in the bath), and the HGB is measured and calculated in the analyzer automatically.

Reticulocytes

Anemia is typically present in 5–10% of small animal samples. In these instances, it is useful to evaluate the blood for the presence of regeneration and RBC abnormalities that may help determine the cause of the anemia. Heska recommends that the best way to assess regeneration is examination of the stained blood film for polychromasia (or reticulocytes), while also looking for RBC abnormalities. The Element HT5 analyzer’s identification of an increase in RDW and/or MCV is evidence of probable reticulocytosis, but this is best confirmed by slide examination.

Sample Pathology Messages

The Element HT5 system provides intelligent information messages related to pathology present in the sample. These messages are intended to be a guide to sample result criteria for slide review that may be used in a laboratory. These messages are indications that additional diagnostic information may be found on the slide to supplement the instrument results.

Dimensions