Analysis of addenda in anatomic pathology as a quality monitoring initiative.

CONTEXT: Along with the integration of immunohistochemical markers and molecular techniques into routine practice, addenda in surgical pathology reporting have not only increased in frequency but also evolved to include prognostic and therapeutic information. Because of the lack of uniform practice with respect to issuing addenda, information that can significantly change the diagnosis, prognosis, or treatment plan may be issued as an addendum as opposed to an amendment. OBJECTIVE: To audit addenda and identify instances of amendments masquerading as addenda. DESIGN: All addenda during a 36-month period were reviewed. Each addendum report was classified by accession class, issuing pathologist, subspecialty category, indication for addendum, whether the addendum constituted a change in diagnostic meaning, whether a change in prognosis occurred, and if a change in treatment plan was necessary. RESULTS: All cytology and autopsy addenda were deemed appropriate. Thirty-three of 5028 (6.5 of 1000) surgical pathology addenda were deemed to have changes: Among the 33 faux addenda, 30 (91%) contained supplemental diagnostic information that would alter patient management and 31 (94%) contained additional information that would change the prognosis from that entailed by the original diagnosis. CONCLUSIONS: Our study demonstrates that not infrequently, surgical pathology addenda contain information that significantly alters the report and thus merit an amendment. Quality monitoring initiatives that evaluate pathologist and departmental performance should assess both addenda and amendments.

Sample features associated with success rates in population-based EGFR mutation testing.

INTRODUCTION: Epidermal growth factor receptor (EGFR) mutation testing has become critical in the treatment of patients with advanced non-small-cell lung cancer. This study involves a large cohort and epidemiologically unselected series of EGFR mutation testing for patients with nonsquamous non-small-cell lung cancer in a North American population to determine sample-related factors that influence success in clinical EGFR testing. METHODS: Data from consecutive cases of Canadian province-wide testing at a centralized diagnostic laboratory for a 24-month period were reviewed. Samples were tested for exon-19 deletion and exon-21 L858R mutations using a validated polymerase chain reaction method with 1% to 5% detection sensitivity. RESULTS: From 2651 samples submitted, 2404 samples were tested with 2293 samples eligible for analysis (1780 histology and 513 cytology specimens). The overall test-failure rate was 5.4% with overall mutation rate of 20.6%. No significant differences in the failure rate, mutation rate, or mutation type were found between histology and cytology samples. Although tumor cellularity was significantly associated with test-success or mutation rates in histology and cytology specimens, respectively, mutations could be detected in all specimen types. Significant rates of EGFR mutation were detected in cases with thyroid transcription factor (TTF)-1-negative immunohistochemistry (6.7%) and mucinous component (9.0%). CONCLUSIONS: EGFR mutation testing should be attempted in any specimen, whether histologic or cytologic. Samples should not be excluded from testing based on TTF-1 status or histologic features. Pathologists should report the amount of available tumor for testing. However, suboptimal samples with a negative EGFR mutation result should be considered for repeat testing with an alternate sample.

Cost analysis of multiplex PCR testing for diagnosing respiratory virus infections.

We performed a cost analysis study using decision tree modeling to determine whether the use of multiplex PCR testing for respiratory viruses (xTAG RVP test) is a more or less costly strategy than the status quo testing methods used for the diagnosis of respiratory virus infections in pediatric patients. The decision tree model was constructed by using four testing strategies for respiratory virus detection, viz., direct fluorescent-antibody staining (DFA) alone, DFA plus shell vial culture (SVC), the xTAG RVP test alone, or DFA plus the xTAG RVP test. A review of the charts of 661 pediatric patients was used to determine the length of hospital stay, the number of days in isolation, antibiotic usage, and all other medical procedures performed. The cost of hospitalization by diagnostic status was determined on the basis of the average cost per patient and the number of patients in each arm of the decision tree. The cost per case was the highest for DFA plus SVC at $3,914 (in Canadian dollars), and the lowest was for the xTAG RVP test alone at $3,623, while the costs of DFA alone ($3,911) and DFA plus RVP ($3,849) were intermediate. When all four diagnostic strategies were compared, the least costly strategy was the xTAG RVP test alone when the prevalence of infection was 11% or higher and DFA alone when the prevalence was under 11%. These data indicate a savings of $291 per case investigated if the strategy of using the xTAG RVP test alone was used to replace the status quo test of DFA plus SVC, resulting in a savings of $529,620 per year in direct costs for the four Hamilton, Ontario, Canada, hospitals on the basis of the testing of specimens from 1,820 pediatric inpatients. We conclude that the use of the xTAG RVP test is the least costly strategy for the diagnosis of respiratory virus infections in children and would generate a significant savings for hospitals.