A haemocytometer is

a specialized, thick glass microscope slide with laser-etched grids, designed for manually counting cells (RBCs, WBCs, sperm) or particles in a specific suspension volume. It features two chambers (often Improved Neubauer) with a

0.1 mm0.1 mm

0.1 mm

depth, allowing for precise cell density calculations, cell viability analysis with dyes like trypan blue, and monitoring cell cultures. 

Key Aspects of a Haemocytometer: 

• Working Principle: Cell suspension is introduced via capillary action; cells are counted under a microscope within specific gridlines to calculate density:

  Cells/mL=Total Counted×Dilution FactorTotal Volume in cm3Cells/mL equals the fraction with numerator Total Counted cross Dilution Factor and denominator Total Volume in cm cubed end-fraction

  Cells/mL=Total Counted×Dilution FactorTotal Volume in cm3.
• Applications: Essential in clinical labs for blood cell counts (RBCs:

  ∼4.2–6.1×106/μLtilde 4.2 – 6.1 cross 10 to the sixth power / mu L

  ∼4.2–6.1×106/????L, WBCs) and in microbiology/cell biology for counting yeast, sperm, or culture cells.
• Common Errors: Overfilling the chamber, uneven distribution of cells, or improper cleaning (use 70% ethanol) can lead to inaccurate counts.