Patient safety in anatomic pathology: measuring discrepancy frequencies and causes.

CONTEXT: Anatomic pathology discrepancy frequencies have not been rigorously studied.
OBJECTIVE: To determine the frequency of anatomic pathology discrepancies and the causes of these discrepancies.
DESIGN: Participants in the College of American Pathologists Q-Probes program self-reported the number of anatomic pathology discrepancies in their laboratories by prospectively performing secondary review (post-sign-out) of 100 surgical pathology or cytology specimens. Reasons for the secondary review included conferences, external review, internal quality assurance policy, and physician request. PARTICIPANTS: Seventy-four laboratories self-reported data. MAIN OUTCOME MEASURES: Frequency of anatomic pathology discrepancy; type of discrepancy (ie, change in margin status, change in diagnosis, change in patient information, or typographic error); effect of discrepancy on patient outcome (ie, no harm, near miss, or harm); and clarity of report.
RESULTS: The mean and median laboratory discrepancy frequencies were 6.7% and 5.1%, respectively. Forty-eight percent of all discrepancies were due to a change within the same category of interpretation (eg, 1 tumor type was changed to another tumor type). Twenty-one percent of all discrepancies were due to a change across categories of interpretation (eg, a benign diagnosis was changed to a malignant diagnosis). Although the majority of discrepancies had no effect on patient care, 5.3% had a moderate or marked effect on patient care.Conclusions.-This study establishes a mean multi-institutional discrepancy frequency (related to secondary review) of 6.7%.