Examination of sentinel lymph nodes for breast carcinoma in the frozen section room at the time of surgery is useful and, if positive, can result in completion axillary dissection at that time. To avoid wasting tissue, many pathologists use direct smears to examine these specimens. We sought to determine whether a concentrated smear technique that was subjectively easier to screen was as sensitive as standard direct and imprint smears. Eighty-five histologically positive lymph nodes were examined in the frozen section room by intraoperative cytology during the study period (35 using routine direct or imprint smears and 50 with a concentrated technique in which cells are spread in an area of < or = 1 cm(2)); 44 (52%) were identified as positive. Positive cytologic results correlated strongly with the size of the metastatic focus (P < .0001). The sampling sensitivity of the concentrated technique was 60% vs 39% for routine direct or imprint smears (P = .08). There were 3 screening errors in the routine smears and none in the concentrated smears (P = .08). The concentrated technique is as sensitive as routine direct smears for sampling sentinel nodes for breast carcinoma and may be associated with a lower screening error rate.