On-site adequacy assessments for image-directed fine needle aspirations: a study of 341 cases.

On-site adequacy assessments (OSAA) are reported to decrease the unsatisfactory and nondiagnostic rates of fine needle aspirations (FNAs). These have been routine in many institutions but were only recently introduced to our large teaching hospital. The results of FNAs performed in diagnostic radiology between January to December 1992 were compared to aspirations done by the same clinical staff during the first year (1993) after the addition of an on-site adequacy assessment service. In the year prior to OSAA, 154 FNAs were performed in diagnostic radiology and the material obtained was processed by a cytotechnologist. Of these, 89 (58%) cases were positive for malignant cells. Approximately half of these cases had confirmatory tissue biopsies processed in the surgical pathology department of our institution. The remaining 65 (42%) of cytology specimens were determined to be negative or nondiagnostic for malignancy. These canes either had no tissue follow-up or the tissue obtained was nondiagnostic. Before beginning OSAA, nine cases (6%) were interpreted as negative for malignancy, but subsequent tissue biopsies were malignant. There were no false positives during this time. Diagnostic sensitivity was 86% before OSAA. One hundred seventy-seven image directed FNAs were performed in the first year following the establishment of OSAA. Of these, 102 (58%) cases were interpreted as positive for malignant cells. About half of these patients went on to have confirmative tissue biopsies. Fifty-six (32%) cases were interpreted as negative for malignancy or nondiagnostic on FNA and follow-up tissue biopsies were also either negative or nondiagnostic. The false negative rate was 1% after OSAA and there were no false positives during this period. Diagnostic sensitivity was 98% after OSAA. In addition, the average overall number of passes per patient have decreased from 2.4 before OSAA to 1.6 after OSAA.