A high-power field (HPF), when used in relation to

microscopy Microscopy is the technical field of using microscopes to view subjects too small to be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of microscopy: optical mic ...

, references the

field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...

under the maximum magnification power of the objective being used. Often, this represents a 400-fold

magnification Magnification is the process of enlarging the apparent size, not physical size, of something. This enlargement is quantified by a size ratio called optical magnification. When this number is less than one, it refers to a reduction in size, so ...

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 *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 Reference ranges for urine tests are described below: See also * Reference range * Reference ranges for blood tests References {{Urine tests Nephrology ...

.Normal Reference Range Table
from the

University of Texas Southwestern Medical Center The University of Texas Southwestern Medical Center (UT Southwestern or UTSW) is a public academic health science center in Dallas, Texas. With approximately 23,000 employees, more than 3,000 full-time faculty, and nearly 4 million outpatient ...

. 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 Mitosis () is a part of the cell cycle in eukaryotic cells in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis is an equational division which gives rise to genetically identical cells in which the ...

per high-power field, cellularity, pleomorphism, and an estimate of the extent of

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

(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:

References

Microscopy {{optics-stub