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

microscopy Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot 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 micr ...

, references the

field of view The field of view (FoV) is the extent of the observable world that is 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 electromagnetic radiation. Human ...

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 calculated number also called "magnification". When this number is less than one, it refers to a reduction in si ...

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 In medicine and health-related fields, a reference range or reference interval is the range or the interval of values that is deemed normal for a physiological ...

.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 university, public Academic health science centre, academic health science center in Dallas, Texas. With approximately 18,800 employees, more than 2,900 ful ...

. 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 In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is maintai ...

per high-power field, cellularity,

pleomorphism Pleomorphism may refer to: * Pleomorphism (cytology), variability in the size and shape of cells and/or their nuclei * Pleomorphism (microbiology), the ability of some bacteria to alter their shape or size in response to environmental conditions ...

, 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. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

(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 Breast cancer classification divides breast cancer into categories according to different schemes criteria and serving a different purpose. The major categories are the histopathological type, the grade of the tumor, the stage of the tumor, and th ...

References

Microscopy {{optics-stub