Eosinophils (E) are a type of leukocyte, accounting for 0.5%–5% of the total leukocyte count. The working principle of Eosinophil Dilution is as follows: blood is diluted with an appropriate volume of Eosinophil Dilution, and eosinophils are stained red in the presence of Phloxine B, while red blood cells and other leukocytes rupture or lyse. Occasionally, a small number of them remain intact but will not be stained by eosin. The diluted blood is loaded into the counting chamber, and the number of eosinophils in a defined volume is counted under a microscope to calculate the eosinophil concentration per liter of blood. This Eosinophil Dilution is for research use only and not intended for clinical diagnosis.
Operating Procedures (For Reference Only):
1. Take a small test tube and add Eosinophil Dilution to it.
2. Use a clean, dry micropipette to draw peripheral blood, add it to the Eosinophil Dilution, and mix thoroughly.
3. After the red blood cells have lysed, load the diluted blood into both sides of the counting chamber, taking care to avoid bubble formation or overflow. Allow to stand at room temperature for 3–5 minutes to let eosinophils sediment.
4. Place the counting chamber under a low-power microscope (a high-power microscope may be used if necessary) and count the number of eosinophils in 10 large squares across the two counting chambers in sequence.
Calculation: Eosinophil count/L = Number of eosinophils in 10 medium squares × 20 × 10⁶/L
Precautions:
1. Counting should be completed within 1 hour after blood dilution; otherwise, eosinophils will be gradually damaged.
2. Mix the diluted blood thoroughly before loading it into the counting chamber, and avoid applying excessive force during the loading process.
3. Distinguish eosinophils from neutrophils; the latter are generally unstained or occasionally pale red with smaller granules.
4. If the number of eosinophils is low, the counting area can be increased.
5. For your safety and health, wear a lab coat and disposable gloves during operation.
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