High-power field
A high-power field, 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 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
- 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.
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. Mitotic counts and necrosis
are the most important predictors.
The following grading is part of classification of breast cancer:
