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HPFitis is use of HPF (high-power field) without proper qualification, i.e. without giving the field area.

HPF redirects here.


Its etiology is thought to be either:

  1. Ignorance of statistics and sampling theory.
  2. Laziness.
  3. A combination of the above two.

It appears to have a higher incidence in math phobic individuals.

Consequences of HPFitis

  • Papers on eosinophilic esophagitis are not comparable.[1]
  • GISTs were improperly staged - until they standardized to 5 mm2.
  • Mitotic score in the Nottingham score for invasive breast cancer is based on the pseudo-standard area of "10 HPFs"; this results in significant variance due to the field area of the microscope in large cohorts.[2]

Field area

Most modern microscopes, have an eye piece diameter of 22 mm. Therefore, the field diameter at 40 X is approximately 22 mm / 40 X ~= 0.55 mm and the field of view is pi/4*(0.55 mm)2 = 0.2376 mm2.

See also


  1. Dellon ES, Aderoju A, Woosley JT, Sandler RS, Shaheen NJ (October 2007). "Variability in diagnostic criteria for eosinophilic esophagitis: a systematic review". Am. J. Gastroenterol. 102 (10): 2300–13. doi:10.1111/j.1572-0241.2007.01396.x. PMID 17617209.
  2. Bonert, M.; Tate, AJ. (Feb 2017). "Mitotic counts in breast cancer should be standardized with a uniform sample area.". Biomed Eng Online 16 (1): 28. doi:10.1186/s12938-016-0301-z. PMC 5312435. PMID 28202066. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312435/.