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High-power field

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 mm<sup>2</sup>
  • AO with 10x eyepiece: 0.12 mm<sup>2</sup>
  • Olympus with 10x eyepiece: 0.16 mm<sup>2</sup>
  • Nikon Eclipse E400 with 10x eyepiece and 40x objective: 0.25mm<sup>2</sup>
  • Leitz Ortholux: 0.27 mm<sup>2</sup>
  • Leitz Diaplan: 0.31 mm<sup>2</sup>

Examples of usage

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

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.

The following grading is part of classification of breast cancer:

References