Final answer:
The correct formula for manual white blood cell count is WBC count = (Number of WBCs counted x Dilution factor) / Volume of blood counted, which accurately calculates the cell count after adjusting for dilutions and the known volume of blood observed.
Step-by-step explanation:
The correct formula to manually calculate the white blood cell (WBC) count is Option 1: WBC count = (Number of WBCs counted x Dilution factor) / Volume of blood counted. This equation takes into account the number of white blood cells counted, the dilution factor which adjusts for the concentration of cells diluted during preparation, and the volume of blood that was actually counted using tools like a hemocytometer or a Petroff-Hausser chamber. The volume of blood counted is typically known and constant due to the standardized grid sizes in these counting tools. The concentration of cells in the original sample is then corrected for the dilution factor to obtain an accurate cell count.