A prospective, multi-Institutional diagnostic trial to determine pathologist accuracy in estimation of percentage of malignant cells

Hollis Viray Dr., Kevin Li, Thomas A. Long, Patricia Vasalos, Julia A. Bridge Dr., Lawrence J. Jennings Dr., Kevin C. Halling, Meera Hameed Dr., David L. Rimm Dr.

Research output: Contribution to journalArticle

52 Scopus citations


Context.-The fraction of malignant cells in tumor tissue submitted for tests of genetic alterations is a critical variable in testing accuracy. That fraction is currently determined by pathologist visual estimation of the percentage of malignant cells. Inaccuracy could lead to a false-negative test result. Objective.-To describe a prospective, multi-institutional study to determine pathologist estimation accuracy. Design.-Ten320 magnification images of hematoxylineosin-stained colon tissue specimens were sent as an educational component of the College of American Pathologists KRAS-B 2011 Survey. Data from 194 labs were analyzed and compared to a criterion standard with comprehensive manual nuclear counts. Results.-Survey responses indicated low interlaboratory precision of pathologist estimation, but mean estimates were fairly accurate. A total of 5 of the 10 cases assessed showed more than 10% of respondents overestimating in a manner that could lead to false-negative test results. Conclusions.-The significance of estimation errors resulting in molecular testing failures with implications for patient care is unknown, but the current study suggests false-negative test results may occur.

Original languageEnglish (US)
Pages (from-to)1545-1549
Number of pages5
JournalArchives of Pathology and Laboratory Medicine
Issue number11
StatePublished - Nov 1 2013


ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Medical Laboratory Technology

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