High-power field

Area visible through the objective of a microscope From Wikipedia, the free encyclopedia

A high-power field (HPF), when used in relation to microscopy, references the field of view under the maximum magnification power of the objective being used. Often, this represents a 400-fold magnification when referenced in scientific papers.

Area

Area per high-power field for some microscope types:

  • Olympus BX50, BX40 or BH2 or AO: 0.096 mm2[1]
  • AO with 10x eyepiece: 0.12 mm2[1]
  • Olympus with 10x eyepiece: 0.16 mm2[1]
  • Nikon Eclipse E400 with 10x eyepiece and 40x objective: 0.25mm2[2]
  • Leitz Ortholux: 0.27 mm2[1]
  • Leitz Diaplan: 0.31 mm2[1]

Examples of usage

The area provides a reference unit, for example in reference ranges for urine tests.[3]

Used for grading of soft tissue tumors: Grading, usually on a scale of I to III, is based on the degree of differentiation, the average number of mitoses per high-power field, cellularity, pleomorphism, and an estimate of the extent of necrosis (presumably a reflection of rate of growth). Mitotic counts and necrosis are the most important predictors.[4]

The following grading is part of classification of breast cancer:

More information Area per HPF, Score ...
Mitotic count per 10 high-power fields (HPFs)[1]
Area per HPFScore
0.096 mm20.12 mm20.16 mm2>0.27 mm20.31 mm2
0-30-40-50-90-111
4-75-86-1010-1912-222
>7>8>10>19>223
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References

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