The Impact of Pathologist Review on Peripheral Blood Smears: A College of American Pathologists Q-Probes Study of 22 Laboratories

The aim of the study was to determine the impact of peripheral blood (PB) smear review by a pathologist when requested by a technologist or provider to measure the rate of pathologist-detected clinically relevant findings. To report and analyze the results of clinically relevant morphologic findings on PB smears that were pathologist reviewed because of either a request from a technologist or an order from a provider. During a 4-week study period, participants enrolled in the College of American Pathologists Q-Probes program submitted data on PB smear reviews including review request source, reason for review request, and if the pathologist's review resulted in a clinically relevant morphologic finding. Twenty-two institutions submitted data on 835 eligible PB smears. Pathologists identified clinically relevant findings on a median 53.4% of technologist-requested PB smear reviews and a median 14.3% of provider-ordered PB smear reviews .The most frequently identified pathologist finding on technologist-requested PB smear reviews was "blasts" in 91 of 532 (17.1%) followed by "atypical (possibly neoplastic) lymphocytes" in 74 of 532 (13.9%); the most frequent finding on provider-ordered reviews was "other" in 55 of 315 (17.5%) followed by "immature cells/left shift in myeloid cells or monocytes" in 12 of 315 (3.8%). Pathologists agreed with technologists' indications for review in 458 of 513 requested reviews (89.3%). Institutions that conducted postanalytic follow-up on previously reviewed PB smears had a higher rate of clinically relevant findings detected on technologist-requested smears. Pathologist review of PB smears flagged by technologists for review frequently yielded clinically relevant findings. This was higher in institutions that conducted postanalytic reviews. Provider-ordered reviews resulted in clinically relevant findings in a median of 14.3% of smears.