[Peer review in toxicologic histopathology: its necessity, type and procedure]

A histopathology peer review already has become an integral part of industrial toxicologic pathology in the USA and Europe. Nevertheless, the review is unfamiliar to toxicologic pathologists in Japan. This report provides detailed information on convenient, useful procedures for peer review in toxicologic histopathology and describes its necessity and type. Histopathology peer review is either informal or formal. Formal review means that the target organs to be re-estimated and the reviewing pathologist's name are stated somewhere in a protocol or study report. The resolution of all diagnostic discrepancies between studies and reviewing pathologists must be clarified, and the review records need to be preserved. No audit trials need to be kept for informal peer review. Based on the purpose of the review, histopathology peer reviews may be classified into 3 major types: "complete", "problem-solving", and a "quality-monitoring" reviews. For a "Complete" review, all histopathologic findings crucial to the conclusion of the study are re-examined. A "problem-solving" review serves to re-evaluate anomalous findings. A "quality-monitoring" review is a periodical monitor of the quality of histopathologic diagnoses at pathology laboratories, particularly in toxicology contract research organizations. The procedures for histopathology peer review consist of 5 stages. At the first stage, the target organs to be reviewed are selected from the draft summary tables of the original findings diagnosed by the study pathologist, and the reviewing pathologist evaluates all selected organs. At the second stage, the study pathologist re-examines all the findings with diagnoses not accepted by the reviewing pathologist and re-considers the appropriateness of these original diagnoses. At the third stage, the study pathologist and the reviewing pathologists discuss all diagnostic differences until they reach a consensus opinion. At the fourth stage, the whole process (stage 1 to 3) of peer review of all target organs is tabulated, including the study pathologist's and reviewing pathologist's diagnoses, the study pathologist's opinions, and consensus diagnoses. At the fifth stage, Peer Review Certification is issued with the study pathologists' and reviewing pathologists' signatures. The reviewing pathologist must share the responsibility for the final diagnoses with the study pathologist. In order to gain greater credibility from regulatory agencies, a peer review performance is best made by an independent external pathologist.