Patient Safety and Quality

Immediate interpretation of lung tissue samples and use of transmucosal fine-needle aspiration reduces pathology errors

Pathology errors occur in 1 to 5 percent of all tissue specimens, with lung specimens having the highest organ-specific error rates. Sampling problems play a major role in misdiagnosis of lung tissues in 97 percent of cases studied, according to a new study. Immediate interpretation at the time of the sampling procedure may reduce lung pathology errors. Researchers suggest that this would allow the pathologist to ask for additional samples or change sampling techniques to obtain an adequate specimen.

With support from the Agency for Healthcare Research and Quality (HS13321), the researchers used root cause analysis to determine the cause of all 32 false-negative bronchial brushing and washing specimen errors, which were obtained from a pathology database at one medical center in 2002. These 32 pathology errors identified abnormal tissue as normal (false-negative), whereas lung biopsy specimens from the same patients found the tissue to be abnormal. Based on a review of the medical records and sample slides for each case, independent reviewers determined that 10 errors were due to poor interpretation of the sample, 16 were due to an inadequate sample, and 6 were due to a combination of poor sampling and interpretation.

Root cause analysis specifically showed that a lesion was not accessible in eight cases and a tumor was readily identified on the slides in only one case. In 11 cases, the malignant cells were few and not recognized, and in 13 cases, obscuring artifacts (for example, cellular crushing and air drying) limited interpretation. In most cases, interpretive error was linked closely to sampling error. An obvious misinterpretation occurred in only one case. In addition to recommending immediate interpretation of samples during the procedure, the researchers also recommend use of transbronchial fine-needle aspiration, use of procedures to remove excess blood or inflammation from samples, and other techniques.

More details are in "Improve the quality of cytology diagnosis," by Laurentia Nodit, M.D., Ronald Balassanian, M.D., Daniel Sudilovsky, M.D., and Stephen S. Raab, M.D., in the December, 2005 American Journal of Clinical Pathology 124, pp. 883-892.

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