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 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.Normal Reference Range Table 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: + Mitotic count per 10 high-power fields (HPFs)Unless otherwise specified in list/table, then reference is: 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
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