Improving the quality of cytology diagnosis: root cause analysis for errors in bronchial washing and brushing specimens.

Detailed root cause analysis to determine causes of pulmonary cytology errors has not been used to design specific practice changes. We performed root cause analysis of all false-negative bronchial brushing and washing specimen errors (n = 32) detected by the cytologic-histologic correlation process in 2002. Medical records and all slides were reviewed. Based on the correlation process, 10 errors were interpretive, 16 sampling, and 6 combined interpretive/sampling. Root cause analysis showed that the lesion was not accessible in 8 cases and tumor was readily identified on the slides in only 1 case. In 11 cases, the malignant cells were few and not recognized, and in 13 cases, obscuring artifacts (eg, cellular crushing and air drying) limited interpretation. Sampling issues had a major role in the misdiagnosis in 31 cases (97%), and recommendations for error reduction include immediate interpretation and the use of transmucosal fine-needle aspiration.