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[1]
- AO with 10x eyepiece: 0.12 mm2[1]
- Olympus with 10x eyepiece: 0.16 mm2[1]
- Nikon Eclipse E400 with 10x eyepiece and 40x objective: 0.25mm2[2]
- Leitz Ortholux: 0.27 mm2[1]
- Leitz Diaplan: 0.31 mm2[1]
Examples of usage
The area provides a reference unit, for example in reference ranges for urine tests.[3]
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.[4]
The following grading is part of classification of breast cancer:
| Area per HPF | 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 |
References
- ^ a b c d e f Unless otherwise specified in list/table, then reference is: "Infiltrating Ductal Carcinoma of the Breast (Carcinoma of No Special Type)". Stanford University School of Medicine. Retrieved 2019-10-02.
- ^ Mikael Häggström (2020-01-29). "Neuroendocrine tumors of the midgut". Patholines.org.
- ^ Normal Reference Range Table Archived 2011-12-25 at the Wayback Machine from the University of Texas Southwestern Medical Center. Used in interactive case study companion to pathologic basis of disease.
- ^ Robbins Basic Pathology, 9e pg 792