"The required total count of mitoses is per 5 mm² on the glass slide section. With the use of older
model microscopes, 50 HPF is equivalent to 5 mm². Most modern microscopes with wider 40x lenses/fields
require only 20 HPF to embrace 5 mm2. If necessary please measure field of view to accurately determine
actual number of fields required to be counted on individual microscopes to count 5 mm². (ref: CAP GIST Protocol)"