11. Automation

Impact on Patient Results:
- Automation has significantly improved the precision and accuracy of hematological results.
- Fewer manual techniques are required with the advancement and implementation of automated processes.
Advancements in Blood Smears:
  - Automation in blood smears has progressed:
    - From a three-part differential,
    - To a five-part differential,
    - Currently, a seven-part differential is utilized.
Timely Diagnosis and Efficient Management:
- Automated reticulocyte counts and the addition of multiple indices enhance diagnostic efficacy.
- These advancements contribute to more effective treatment of diseases and improved patient management.

Definition:
- Histograms are graphic representations depicting the relationship between cell frequencies and sizes.
Data Representation:
  - Pulses are channelized by height or amplitude.
  - Data is plotted on a volume/frequency distribution histogram:
    - Y-Axis: Relative number of cells.
    - X-Axis: Size or volume of cells.
Measurement Parameters:
  - Created for various blood components:
    - Erythrocytes (red blood cells),
    - Leukocytes (white blood cells),
    - Platelet populations.
  - Measurements are based on cell volume measured in femtoliters (fL) and relative numbers.

Process Overview:
- Cells are counted and sized by measuring changes in electrical resistance as they pass through a small aperture.
Sample Preparation:
- Blood sample is diluted in saline, which conducts electrical current effectively.
Detection Method:
  - Cells are drawn through the aperture by creating a vacuum.
  - Two electrodes establish an electrical current:
    - External Electrode: Located in the cell suspension.
    - Internal Electrode: Inside the glass hollow tube containing the aperture.
  - Current Application:
    - Low-frequency electrical current is applied to both electrodes.
    - Direct current (DC) is applied between the electrodes to measure impedance.
Outcome:
- Electrical resistance or impedance generates a voltage change as cells traverse the aperture, resulting in a pulse count.
- The number of pulses correlates with the number of RBCs counted using electrical impedance techniques.

Technique Overview:
- A method that narrows the stream of cells into a single file, allowing for enhanced accuracy and resolution in counting blood cells.
Flow Management:
- Aligns cells in single-file order as they pass through the detection aperture.
- Directs cells away from the back of the aperture to eliminate counting duplicates.

Interpretation of Results:
  - Morph. Zählg. DIFF, contrast of various wbc and rbc parameters, including counts and ratios:
    - Example readings:
      - WBC Count: 4.13 [10/μL],
      - RBC Count: 4.34 [10/μL],
      - Hemoglobin (Hgb): 8.2 [mmol/L],
      - Hematocrit (HCT): 0.392 [L/L],
      - Mean Corpuscular Volume (MCV): 90.3 [fL],
      - Mean Corpuscular Hemoglobin (MCH): 1.889 [fmol].
      - Many other indices listed with their respective values.

Overview:
- Histograms categorize RBC sizes as:
- Normal, Microcytic, etc.
Data Points:
- Displayed numerically and graphically across various parameters related to size and count.

Definition:
- Scatterplots visually represent two or more measurable characteristics of cells using graphical methods.
Advanced Visualization:
- Utilize conductivity and light scatter for data analysis.
- Facilitate detection of population abnormalities and allow for analysis of subpopulations.
Key Populations:
- Prominent cell populations visualized include lymphocytes, granulocytes, and monocytes.

Basic Principles:
- Employs a laser light source to determine physical or antigenic properties of cells passing through the light beam.
Data Measurements:
- Cell metrics include:
- Size, nuclear complexity, cell granularity, and staining capacity.
Light Scatter:
  - Measured at angles:
    - Forward light scatter (FALS) at 2 to 10 degrees for cell size,
    - Side scatter (SSC) at 70 to 90 degrees for cytoplasmic and nuclear complexity.
Processing:
- Light scatter signals are digitally converted and plotted to create scattergrams that categorize cells.
- Classification into clusters helps identify granulocytes, monocytes, and lymphocytes.

Methodology:
- Hemoglobin measurements are conducted primarily via spectrophotometry.
Technique Specification:
- The cyanmethemoglobin method is standard, but modern analyzers often utilize non-cyanide methods for improved safety and reduced environmental impact.

Testing Methodologies:
- Coagulation assays can employ various techniques including chromogenic and immunologic measurement.

Electromechanical Clot Detection:
- Involves the use of two metal electrodes measuring conductivity changes due to fibrin formation.
- Current interruption stops a timer upon clot formation.
Electromagnetic Clot Detection:
- Utilizes viscosity changes in the plasma sample; oscillation of a metal ball slows as viscosity increases, signaling clot formation.
- Typical methodology employed in Stago analyzers.

Detection Method:
  - Based on optical density adjustments as turbidity changes;
  - As fibrinogen converts to fibrin, turbidity increases through absorption of light.
  - Changes in optical density are logged and converted to electrical signals.
Devices and Techniques:
- Stago analyzers utilize this method particularly for D-Dimer assays.
Nephelometry:
- Variation of photometric detection, measuring light scattered at 90-degree side and 180-degree forward angles.
- Provides quantitative measurements and generates clot curves.

Mechanism:
  - Utilizes a color-generating substance (chromophore) linked to synthetic peptides for testing.
  - The enzyme cleaves the chromophore in response to protease activity, allowing measurement of free para-nitroaniline (pNA) at 405 nm.
  - The yellow coloration indicates the concentration of pNA relative to coagulation activity (e.g., monitoring heparin therapy).
  - Stago instruments implement this functionality.

Principle of Operation:
  - Involves latex particle agglutination in response to antigens.
  - Light absorption increases as agglutinate forms due to clot formation with an increase in antigen levels.
  - Commonly utilized for D-dimer testing within Stago tools.