What does HPF stands for in a Clinical Laboratory report? Usually this can be seen on the WBC or RBC field?

Answer 1

HPF means high power field
in light microscopes, 3 kinds of lenses are used:
light power field (magnifies 10 times)
high power field (magnifies 40 times)
immersion lense (magnifies 100 times)

so the counting is done in HPF, under light microscope using high power field. the result shows like:
4-5/HPF. it means 4-5 cells in HPF.

Answer 2

High power field. Under microscope field seen through high power lens.