High-power field
{{Short description|Area visible through the objective of a microscope}}
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
- AO with 10x eyepiece: 0.12 mm2
- Olympus with 10x eyepiece: 0.16 mm2
- Nikon Eclipse E400 with 10x eyepiece and 40x objective: 0.25mm2{{cite web|url=https://patholines.org/Neuroendocrine_tumors_of_the_midgut|title=Neuroendocrine tumors of the midgut|author=Mikael Häggström|date=2020-01-29|website=Patholines.org}}
- Leitz Ortholux: 0.27 mm2
- Leitz Diaplan: 0.31 mm2
Examples of usage
The area provides a reference unit, for example in reference ranges for urine tests.[http://pathcuric1.swmed.edu/PathDemo/nrrt.htm Normal Reference Range Table] {{webarchive|url=https://web.archive.org/web/20111225185659/http://pathcuric1.swmed.edu/PathDemo/nrrt.htm |date=2011-12-25 }} from the University of Texas Southwestern Medical Center. Used in interactive case study companion to pathologic basis of disease.
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.Robbins Basic Pathology, 9e pg 792
The following grading is part of classification of breast cancer:
| class="wikitable"
|+ Mitotic count per 10 high-power fields (HPFs)Unless otherwise specified in list/table, then reference is: {{cite web|url=http://surgpathcriteria.stanford.edu/breast/infductcabr/grading.html|title=Infiltrating Ductal Carcinoma of the Breast (Carcinoma of No Special Type)|website=Stanford University School of Medicine|accessdate=2019-10-02|archive-date=2019-09-11|archive-url=https://web.archive.org/web/20190911054536/http://surgpathcriteria.stanford.edu/breast/infductcabr/grading.html|url-status=dead}} !colspan=5| Area per HPF !!rowspan=2| Score | |||||
| 0.096 mm2 | 0.12 mm2 | 0.16 mm2> | 0.27 mm2 | 0.31 mm2 | |
|---|---|---|---|---|---|
| 0-3 | 0-4 | 0-5 | 0-9 | 0-11 | 1 |
| 4-7 | 5-8 | 6-10 | 10-19 | 12-22 | 2 |
| >7 | >8 | >10 | >19 | >22 | 3 |