Parasite Counting Formula

Question: Please send me malaria parasite counting formula

Answer: Malaria parasites are usually counted against white blood cells using a thick blood smear under a microscope. The person reading the slide should use two tally counters, one for malaria and one for the white blood cells. (Note – Some tally counters can take multiple tallies at the same time, which means only one tally counter would be needed.) Starting at the top-left of the slide, count all the malaria parasites and white blood cells (tallying each count separately) in the field of view. When finished, move to a new field of view (being careful not to overlap with the previous field) and continue counting, and so on. Finish counting depending on the number of malaria parasites observed

• If you have counted ≥ 100 parasites in 200 white cells, stop counting, and record the results as the number of parasites per 200 white cells.
• If you have counted ≤ 99 parasites in 500 white cells, stop counting, and record the results as the number of
  parasites per 500 white cells.

Finish counting all the malaria parasites and white blood cells in the final field.

When you are finished counting, use the patient’s actual white blood cell count to calculate the patient’s parasite density. If the white blood cell count is not available, use 8000 white blood cells/µL as an estimated average value. Use the below formula to calculate parasite density:

Parasites/µL blood = (Number of parasites counted x 8000 white blood cells/µL) / No. of white blood cells counted