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American Society of Clinical Oncology/College of American Pathologists guideline recommendations for human epidermal growth factor receptor 2 testing in breast cancer.

PURPOSE: To develop a guideline to improve the accuracy of human epidermal growth factor receptor 2 (HER2) testing in invasive breast cancer and its utility as a predictive marker. METHODS: The American Society of Clinical Oncology and the College of American Pathologists convened an expert panel, which conducted a systematic review of the literature and developed recommendations for optimal HER2 testing performance. The guideline was reviewed by selected experts and approved by the board of directors for both organizations. RESULTS: Approximately 20% of current HER2 testing may be inaccurate. When carefully validated testing is performed, available data do not clearly demonstrate the superiority of either immunohistochemistry (IHC) or in situ hybridization (ISH) as a predictor of benefit from anti-HER2 therapy. RECOMMENDATIONS: The panel recommends that HER2 status should be determined for all invasive breast cancer. A testing algorithm that relies on accurate, reproducible assay performance, including newly available types of brightfield ISH, is proposed. Elements to reliably reduce assay variation (for example, specimen handling, assay exclusion, and reporting criteria) are specified. An algorithm defining positive, equivocal, and negative values for both HER2 protein expression and gene amplification is recommended: a positive HER2 result is IHC staining of 3+ (uniform, intense membrane staining of > 30% of invasive tumor cells), a fluorescent in situ hybridization (FISH) result of more than six HER2 gene copies per nucleus or a FISH ratio (HER2 gene signals to chromosome 17 signals) of more than 2.2; a negative result is an IHC staining of 0 or 1+, a FISH result of less than 4.0 HER2 gene copies per nucleus, or FISH ratio of less than 1.8. Equivocal results require additional action for final determination. It is recommended that to perform HER2 testing, laboratories show 95% concordance with another validated test for positive and negative assay values. The panel strongly recommends validation of laboratory assay or modifications, use of standardized operating procedures, and compliance with new testing criteria to be monitored with the use of stringent laboratory accreditation standards, proficiency testing, and competency assessment. The panel recommends that HER2 testing be done in a CAP-accredited laboratory or in a laboratory that meets the accreditation and proficiency testing requirements set out by this document.

Female↗

Method preferences and test accuracy of antimicrobial susceptibility testing: updates from the College of Amercian Pathologists Microbiology Surveys Program.

OBJECTIVE: To summarize the antimicrobial susceptibility testing results from the College of American Pathologists (CAP) Microbiology Surveys Program for 2000. Specifically, the frequency of tests used and the quantitative and qualitative (susceptibility category) accuracy were assessed. DESIGN: The CAP Microbiology Surveys challenged subscribers in 2000 with 3 well-characterized organisms for antimicrobial susceptibility testing in pure culture. Each laboratory was to use the test method and reporting procedures routinely applied to patient samples. The strains were National Committee for Clinical Laboratory Standards (NCCLS) quality control organisms with precisely defined antimicrobial susceptibility patterns and reproducibility. Results reported by participants (2685-2979/sample) were graded for categorical accuracy and quantitative performance by comparing reported minimal inhibitory concentrations (microg/mL) or zone diameters (mm) against quality control ranges published by the NCCLS. The appropriateness of reported drugs was determined in the context of the type and anatomic location of the infection. RESULTS: The tests most often used varied by the species of the organism and growth characteristics of the isolated strains. Nonfastidious, rapid-growing Surveys unknowns (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) were most often tested with commercial systems (MicroScan, 42.0%-42.4%; Vitek, 41.5%-43.0%) or with the standardized disk diffusion method (12.8%-13.9%). In contrast, fastidious species, such as Streptococcus pneumoniae (ATCC 49619), were predominantly tested by Etest (40.3%), followed by disk diffusion (27.6%) and MicroScan (23.2%). Categorical accuracy was essentially equal between dilution (98.9%) and diffusion (99.0%) methods. Among the minimal inhibitory concentration methods used to test penicillin against S pneumoniae, Etest method quantitative accuracy (96.3%) was greater than that of MicroScan (92.4%). Quantitative accuracy was greatest for dilution minimal inhibitory concentration methods, with more than 90% of results within NCCLS quality control ranges for nearly all reported antimicrobials. Reevaluations of quality control ranges may be needed for 4 to 7 agents, depending on method. Reporting errors were also detected in 2 areas: (1) reporting results for drugs not active at the site of infection and (2) reporting results for drugs tested with suboptimal methods without published NCCLS interpretive criteria. CONCLUSIONS: Antimicrobial susceptibility testing methods used in US laboratories were dominated by commercial products with relatively high accuracy (qualitative and quantitative). As available methods have become better suited to both fastidious and rapid-growing species, reporting errors have assumed a higher level of concern to the CAP Surveys in an effort to minimize prescription errors.

Anti-Bacterial Agents↗

A longitudinal replicate study of immunosuppressive drugs: a College of American Pathologists study.

OBJECTIVE: To identify the sources of analytical variation for cyclosporine and tacrolimus in a 3-year longitudinal study. DESIGN: Two pools of whole blood were spiked with cyclosporine and tacrolimus, respectively. One aliquot of cyclosporine and 2 of the tacrolimus pool were distributed in the first and last mailing for years 1999 to 2001. For both drugs, the total variance for each method was partitioned into within- and between-laboratory components. SETTING: The A and C mailings of the 1999, 2000, and 2001 AACC/CAP [American Association for Clinical Chemistry/College of American Pathologists] Immunosuppressive Drugs (CS) Monitoring Survey. MAIN OUTCOME MEASURES: For each drug, total variance was partitioned into specimen, mailing, year, and interlaboratory effects for each analytical method. PARTICIPANTS: The 292 laboratories for cyclosporine and 177 laboratories for tacrolimus enrolled in the survey from 1999 to 2001. RESULTS: For both cyclosporine and tacrolimus, the major source of imprecision came from within-laboratory factors, which accounted for nearly 85% (range, 77% to 90%) of the total variance. For cyclosporine, the major component of within-laboratory variance was between-mailing, within-year effect, whereas for tacrolimus it was the between-year, within-laboratory variation. CONCLUSION: The major source of long-term survey imprecision for cyclosporine and tacrolimus is within-laboratory factors. The finding that 85% of the total variance was due to within-laboratory variation is similar to other therapeutic drugs.

Analysis of Variance↗

Type and screen completion for scheduled surgical procedures. A College of American Pathologists Q-Probes study of 8941 type and screen tests in 108 institutions.

CONTEXT: Market-driven changes in the timing of elective surgeries and admissions have introduced barriers to completing pretransfusion testing in a timely manner. Consequently, blood bank personnel may not have adequate time to identify appropriate blood products for scheduled surgeries. Incomplete pretransfusion testing can delay surgery and significantly compromise patient safety. OBJECTIVES: To identify the incidence of avoidable problems associated with obtaining timely samples for adequate pretransfusion type and screen (T&S) testing, to identify the practices and characteristics associated with improved rates of pretransfusion testing completed prior to surgery, and to determine the likelihood of antibody identification problems that affect the availability of blood. DESIGN: Participants in the College of American Pathologists (CAP) Q-Probes laboratory quality improvement program were asked to collect data on when a T&S was collected in anticipation of elective scheduled surgery, when the T&S was completed, when the surgery started, and the results of those T&S tests. Participants also completed questionnaires describing their facilities, procedures, and practices. SETTING AND PARTICIPANTS: One hundred eight public and private institutions participated in this Q-Probes Study, 97% of which were located in the United States. MAIN OUTCOMES MEASURES: Type and screen collection and completion relative to the start of surgery, and the results of those tests. RESULTS: Of the 8941 T&Ss, 64.6% were collected prior to the day of surgery. The median laboratory completed approximately 69% of their T&S testing for scheduled surgeries at least 1 day prior to the surgery. Of those T&S tests that were collected on the day of surgery, the median laboratory completed almost 23% after the start of surgery. For 10% of participants, more than 75% of all T&Ss collected on the same day as surgery were not complete until after the start of surgery. When red blood cell-directed antibodies were identified, 78.7% were considered clinically significant, and 95.2% were alloantibodies. Positive antibody screens were significantly associated with delayed surgery and special efforts needed to obtain blood. Of those institutions with a specific protocol in place to collect T&S samples prior to hospital admission, the median laboratory completed the T&S at least 1 day prior to surgery 74% of the time. When the institution coupled the T&S collection protocol with T&S collection earlier than 3 days prior to surgery, the median laboratory completed the T&S at least 1 day prior to surgery almost 87% of the time. Type and screen collection less than 3 days prior to surgery resulted in special efforts needed to obtain blood more than 1% of the time. Type and screen collected on the same day as surgery directly resulted in a surgery delay 0.8% of the time. CONCLUSIONS: Patients are unnecessarily being placed at risk by inadequate mechanisms to ensure available blood for surgery. All T&Ss were collected for scheduled surgeries with adequate opportunity for a T&S to be completed in advance of the surgery. Specific protocols helped improve the performance in terms of completing the T&S prior to surgery, as did mechanisms that permitted T&S collections in advance of the admission. Type and screen collection time relative to surgery was significantly associated with the incidence of surgery delay due to unavailable blood; the less time between collection and surgery, the less likely blood was available.

Accreditation↗

Audit of transfusion procedures in 660 hospitals. A College of American Pathologists Q-Probes study of patient identification and vital sign monitoring frequencies in 16494 transfusions.

CONTEXT: Hemolytic transfusion reactions are often the result of failure to follow established identification and monitoring procedures. OBJECTIVE: To measure the frequencies with which health care workers completed specific transfusion procedures required for laboratory and blood bank accreditation. DESIGN: In 2 separate studies, participants in the College of American Pathologists Q-Probes laboratory quality improvement program audited nonemergent red blood cell transfusions prospectively and completed questionnaires profiling their institutions' transfusion policies. SETTING AND PARTICIPANTS: A total of 660 institutions, predominantly in the United States, at which transfusion medicine services are provided. MAIN OUTCOMES MEASURES: The percentages of transfusions for which participants completed 4 specific components of patient and blood unit identifications, and for which participants monitored vital signs at 3 specific intervals during transfusions. RESULTS: In the first study, all components of patient identification procedures were performed in 62.3%, and all required patient vital sign monitoring was performed in 81.6% of 12 448 transfusions audited. The median frequencies with which institutions participating in the first study performed all patient identification and monitoring procedures were 69.0% and 90.2%, respectively. In the second study, all components of patient identification were performed in 25.4% and all patient vital sign monitoring was performed in 88.3% of 4046 transfusions audited. The median frequencies with which institutions participating in the second study performed all patient identification and monitoring procedures were 10.0% and 95.0%, respectively. Individual practices and/or institutional policies associated with greater frequencies of patient identification and/or vital sign monitoring included transporting units of blood directly to patient bedsides, having no more than 1 individual handle blood units in route, checking unit labels against physicians' orders, having patients wear identification tags (wristbands), reading identification information aloud when 2 or more transfusionists participated, using written checklists to guide the administration of blood, instructing health care personnel in transfusion practices, and routinely auditing the administration of transfusions. CONCLUSIONS: In many hospitals, the functions of identification and vital sign monitoring of patients receiving blood transfusions do not meet laboratory and blood bank accreditation standards. Differences in hospital transfusion policies influence how well health care workers comply with standard practices. We would expect that efforts designed to perfect transfusion policies might also improve performance in those hospitals in which practice compliance is substandard.

Accreditation↗

Productivity of Veterans Health Administration laboratories: a College of American Pathologists Laboratory Management Index Program (LMIP) study.

CONTEXT: The Veterans Health Administration (VA) operates the largest integrated laboratory network in the United States. OBJECTIVE: To assess whether the unique characteristics of VA laboratories impact efficiency of operations, we compared the productivity of VA and non-VA facilities. DESIGN: Financial and activity data were prospectively collected from 124 VA and 131 non-VA laboratories enrolled in the College of American Pathologists Laboratory Management Index Program (LMIP) during 2002. In addition, secular trends in 5 productivity ratios were calculated for VA and non-VA laboratories enrolled in LMIP from 1997 through 2002. RESULTS: Veterans Health Administration and non-VA facilities did not differ significantly in size. Inpatients accounted for a lower percentage of testing at VA facilities than non-VA facilities (21.7% vs 37.3%; P <.001). Technical staff at the median VA facility were paid more than at non-VA facilities (28.11/h dollars vs 22.60/h dollars, salaries plus benefits; P <.001), VA laboratories employed a smaller percentage of nontechnical staff (30.0% vs 41.9%; P <.001), and workers at VA laboratories worked less time per hour paid (85.5% vs 88.5%; P <.001). However, labor productivity was significantly higher at VA than at non-VA facilities (30 448 test results/total full-time equivalent (FTE)/y vs 19 260 results/total FTE; P <.001), resulting in lower labor expense per on-site test at VA sites than at non-VA sites (1.79 dollars/result vs 2.08 dollars/result; P <.001). Veterans Health Administration laboratories paid less per test for consumables (P =.003), depreciation, and maintenance than their non-VA counterparts (all P <.001), resulting in lower overall cost per on-site test result (2.64 dollars vs 3.40 dollars; P <.001). Cost per referred (sent-out) test did not differ significantly between the 2 groups. Analysis of 6-year trends showed significant increases in both VA (P <.001) and non-VA (P =.02) labor productivity (on-site tests/total FTE). Expenses at VA laboratories for labor per test, consumables per test, overall expense per test, and overall laboratory expense per discharge decreased significantly during the 6-year period (P <.001), while in non-VA facilities the corresponding ratios showed no significant change. CONCLUSIONS: Overall productivity of VA laboratories is superior to that of non-VA facilities enrolled in LMIP. The principal advantages enjoyed by the VA are higher-than-average labor productivity (tests/FTE) and lower-than-average consumable expenses.

Efficiency, Organizational↗

Lack of specificity of cyclosporine immunoassays. Results of a College of American Pathologists Study.

OBJECTIVE: To evaluate the cross-reactivity of the 6 most abundant cyclosporine A (CsA) metabolites in commonly used assays for CsA. DESIGN: Whole blood samples containing either only 62 ng/mL CsA (A) or 62 ng/mL CsA and between 49 and 86 ng/mL of 1 of the 6 most abundant CsA metabolites (B) were lyophilized. One sample of A and 1 of B were mailed to each of the laboratories participating in the College of American Pathologists Proficiency Testing Program quarterly during a 3-year period (1999-2001). Method means and coefficients of variation were calculated for each mailing. RESULTS: The study showed significant cross-reactivity of metabolites in all the immunoassay systems studied. Overall degree of interference decreased from Abbott TDx polyclonal > Abbott TDx monoclonal > DiaSorin > Syva EMIT. High-performance liquid chromatography methods gave results close to those found using mass spectrometric techniques. CONCLUSIONS: Significant metabolite interference was found to occur with the immunoassay systems studied.

Chromatography, High Pressure Liquid↗

Results of the survey of the quality assurance for commercially prepared microbiology media. Update from the College of American Pathologists Microbiology Surveys Program (2001).

CONTEXT: Beginning in 1985, state-of-the-art surveys by the College of American Pathologists (CAP) led to M22-A guidelines by the National Committee for Clinical Laboratory Standards (NCCLS) for quality assurance (QA) of various commercially prepared isolation and diagnostic microbiology media. Some medium types were declared exempt from routine QA testing by each laboratory user, but manufacturer QA was maintained and specified in great detail. No update has occurred in more than 15 years as more complex media have been introduced into clinical microbiology practice. OBJECTIVE: To reassess the quality of commercially prepared microbiology media in the United States for the revision of NCCLS document M22-A2. Methods.-A questionnaire was designed to conform to that used by the CAP in 1985 and 1988, and was updated by lists of 52 recently introduced diagnostic media. Queries included details of laboratory QA in the last 12 months, such as number of lots tested, number of items in a lot, number of items in a quality control (QC) sample, number of lots failed, and reasons for lot failure. All CAP Microbiology Surveys participants received the document in late 2001. RESULTS: Data from nearly 300 000 media lots representing 32.7 million medium items were received from more than 3000 CAP Surveys subscribers. Lot raw data failure rates for all media ranged from 0.10% to 9.87% (average, 1.01%). Failures with media having a significant QC experience (> or =1000 lots or > or =100 000 items) adjusted for QC strain-based failures (so-called extrapolated failure rate) ranged from 0.04% to 1.34% (average, 0.40%). The threshold rate for QA exemption from 1985 analyses was expanded to 0.50% or less and now allows exemption of 27 media evaluated in this study. Local laboratory QA must remain in force (M22-A2) for the other 25 products. CONCLUSIONS: Generated QA failure results from the CAP Microbiology Surveys supplement recent results of the NCCLS M22 Subcommittee that will lead to more practical media QA guidelines and could significantly decrease costs for clinical microbiology laboratories through focusing QC on a smaller number of the most at-risk diagnostic products.

Bacteria↗

Cytologic features of squamous cell carcinoma in ThinPrep slides: evaluation of cases that performed poorly versus those that performed well in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

CONTEXT: Although the cytologic features of squamous cell carcinoma in ThinPrep specimens are well known, whether these features are different in cases that are easily identified than in cases that are more difficult to identify is not known. OBJECTIVE: To determine the cytologic features of squamous cell carcinoma in ThinPrep specimens that are easy to identify versus those that are difficult. DESIGN: The cytologic features of 6 cases of squamous cell carcinoma that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 14 cases that performed extremely well. RESULTS: After evaluation of multiple criteria, 7 different cytologic features were analyzed based on review by a consensus panel blinded to the performance of the cases. The feature that was most strongly associated with cases that performed poorly was the presence of Trichomonas vaginalis (5/6 [83%] vs 0/14; P <.001). The presence of marked nuclear pleomorphism was more common in cases that performed well (4/14 [28%] vs 0/6; P =.27), but was not significant. The number of tumor cells, the number of normal cells, and the presence of keratinization, pleomorphism, nucleoli, and diathesis were not significant. The most common misdiagnosis after Trichomonas vaginalis was reparative change. CONCLUSIONS: The presence of Trichomonas is characteristic of cases of squamous cell carcinoma in ThinPrep slides that are often misdiagnosed in this program. While Trichomonas is identified by participants in some of these cases, a significant percentage of participants interpreted the findings as reparative, without identifying the organism. These results emphasize the importance of distracting factors, whether identified or not, in evaluating gynecologic cytology.

Carcinoma, Squamous Cell↗

Fluids--good and bad actors: observations from the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytology.

CONTEXT: Body cavity fluid examination presents a common and sometimes difficult diagnostic challenge in daily cytology practice. Separating benign from malignant cellular changes may require meticulous screening, careful scrutiny of cellular features, and an understanding of the range of reactive changes. We use the data from the College of American Pathologists (CAP) Interlaboratory Comparison Program in Nongynecologic Cytology (NGC) to identify characteristics of fluids that place them at opposite ends of the diagnostic spectrum. OBJECTIVE: To assess the features of individual body cavity fluid slides that demonstrated good performance characteristics and compare them to slides that were poor performers. DESIGN: A databank of 10 396 laboratory responses, including a variety of malignant and benign cases obtained from 1997 through 2001, was used to select cases. A cumulative slide history was used to identify slides that performed well or poorly in each reference diagnosis. Cases were confirmed by consensus of 4 CAP Cytopathology Resource Committee members. Observations and characterizations of good and bad performers in each category were recorded and summarized. RESULTS: Percentage of concordance of poor performers ranged from 0% to 58%. Conversely, good performers were identified with high concordance of laboratory diagnosis in each reference category (>80%). Several patterns emerged. Poorly performing cases of adenocarcinoma consisted of slides with rare tumor cells, hypercellular malignant cases without 2 cell populations, and cases with single cells. Poor performance in confirmed squamous cell carcinoma cases related to rare cells without keratinization. Small cell carcinoma and melanoma cases performed poorly when there were few malignant cells. Lymphoma cases demonstrated poor performance when there were abundant pleomorphic lymphoid cells or when rare Reed- Sternberg-like cells were present. Reactive or negative slides performed best with a polymorphous population; poor performers were those with a predominant lymphocyte population mistaken for a hematopoietic neoplasm. CONCLUSION: Close attention to classic cytologic criteria and careful examination of slides may enhance the educational experience of participants and the performance characteristics of body cavity fluid specimens in the CAP NGC program. Lessons from bad actors in the CAP NGC program may increase awareness of potential diagnostic problems in daily practice or help identify areas for laboratory quality improvement.

Adenocarcinoma↗

Continuous monitoring of stat and routine outlier turnaround times: two College of American Pathologists Q-Tracks monitors in 291 hospitals.

CONTEXT: The laboratory test turnaround times (TATs) that exceed the expectations of clinicians who order those tests, the so-called outlier test reporting rates, may be responsible for perceptions of inadequate laboratory service. OBJECTIVE: To monitor outlier test reporting rates for emergency department stat potassium results and routine inpatient morning blood tests. DESIGN: In 2 different monitors, each conducted for 2 years, laboratory personnel in institutions enrolled in the College of American Pathologists (CAP) Q-Tracks program tracked the percentages of emergency department stat potassium results and/or the percentages of morning rounds routine test results that were reported later than self-imposed reporting deadlines. SETTING: A total of 291 hospitals participating in 2 CAP Q-Tracks monitors. RESULTS: Participants monitored 225,140 stat emergency department potassium TATs, of which 33,402 (14.8%) were outliers, and 1,055040 routine morning test reporting times, of which 123,554 (11.7%) were outliers. For both monitors, there was a significant (P <.05) downward trend in the outlier rates as the number of quarters in which participants submitted data increased. CONCLUSION: Outlier reporting rates for emergency department stat potassium and routine morning test results decreased during the 2-year period of continuous monitoring. The CAP Q-Tracks program provides an effective vehicle by which providers of laboratory services may improve the timeliness with which they deliver the results of laboratory tests.

Clinical Laboratory Techniques↗

Comparative analytical costs of central laboratory glucose and bedside glucose testing: a College of American Pathologists Q-Probes study.

CONTEXT: One of the major attributes of laboratory testing is cost. Although fully automated central laboratory glucose testing and semiautomated bedside glucose testing (BGT) are performed at most institutions, rigorous determinations of interinstitutional comparative costs have not been performed. OBJECTIVES: To compare interinstitutional analytical costs of central laboratory glucose testing and BGT and to provide suggestions for improvement. DESIGN: Participants completed a demographic form about their institutional glucose monitoring practices. They also collected information about the costs of central laboratory glucose testing, BGT at a high-volume testing site, and BGT at a low-volume testing site, including specified cost variables for labor, reagents, and instruments. PARTICIPANTS: A total of 445 institutions enrolled in the College of American Pathologists Q-Probes program. MAIN OUTCOME MEASURE: Median cost per glucose test at 3 testing sites. RESULTS: The median (10th-90th percentile range) costs per glucose test were 1.18 dollars (5.59 dollars-0.36 dollars), 1.96 dollars (9.51 dollars-0.77 dollars), and 4.66 dollars (27.54 dollars-1.02 dollars) for central laboratory, high-volume BGT sites, and low-volume BGT sites, respectively. The largest percentages of the cost per test were for labor (59.3%, 72.7%, and 85.8%), followed by supplies (27.2%, 27.3%, and 13.4%) and equipment (2.1%, 0.0%, and 0.0%) for the 3 sites, respectively. The median number of patient specimens per month at the high-volume BGT sites was 625 compared to 30 at the low-volume BGT sites. Most participants did not include labor, instrument maintenance, competency assessment, or oversight in their BGT estimated costs until required to do so for the study. CONCLUSIONS: Analytical costs per glucose test were lower for central laboratory glucose testing than for BGT, which, in turn, was highly variable and dependent on volume. Data that would be used for financial justification for BGT were widely aberrant and in need of improvement.

Blood Glucose↗

Measuring the significance of field validation in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology: how good are the experts?

CONTEXT: Expert opinion is often used as a gold standard for gynecologic cytology in the evaluation of new technologies, in the legal setting, and in the validation of cases for use in educational programs and proficiency testing. However, the reliability of expert opinion alone in selecting slides of a specific cytodiagnosis that can be reproducibly and reliably identified by subsequent reviewers has not been determined. OBJECTIVE: To assess the ability of expert opinion to select slides that are validated in subsequent reviews. DESIGN: In the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology, each case in every cytodiagnostic category is accepted for circulation only after review by 3 expert cytopathologists. The percentage of these cases that could not be reliably and reproducibly identified by program participants for each cytodiagnostic category ("failed field validation") was determined during the duration of the program from 1989 to 2004. RESULTS: More than 10,000 conventional smears and ThinPrep cases were selected by the expert panel for circulation. Of these selected slides, 19% of conventional smears and 15% of ThinPrep specimens failed field validation. Compared with the overall slide performance, significantly higher percentages (P < .001) of conventional smears with reference diagnoses of unsatisfactory (51.7%), repair (58%), or low-grade intraepithelial lesion (31.8%) and of ThinPrep specimens with reference diagnoses of unsatisfactory (54.5%) and repair (76.9%) failed field validation. In contrast, significantly lower percentages of conventional smears with reference diagnoses of squamous cell carcinoma (4.5%), high-grade squamous intraepithelial lesion (9%), Trichomonas vaginalis infection (11.7%), or herpes (9.9%) and of ThinPrep specimens with reference diagnoses of adenocarcinoma (5.1%), herpes (2.1%), and fungal organism consistent with Candida (8.4%) failed field validation (P < .001 for all). CONCLUSIONS: Between 15% and 19% of gynecologic cytologic cases that have been selected by expert cytopathologists as good examples of cytodiagnostic abnormalities fail field validation. The proportion of cases failing field validation varies with cytodiagnostic category, but it occurs in all cytodiagnostic entities.

Clinical Competence↗

Distinguishing small cell carcinoma from non-small cell carcinoma of the lung: correlating cytologic features and performance in the College of American Pathologists Non-Gynecologic Cytology Program.

CONTEXT: The cytologic features of small cell carcinoma of the lung are well described. Nevertheless, some small cell carcinomas may be difficult to reproducibly distinguish from non-small cell carcinomas, and this distinction carries significant clinical importance. OBJECTIVE: To correlate the cytologic features of individual cases of small cell carcinoma of the lung in fine-needle aspiration specimens from the College of American Pathologists Non-Gynecologic Peer Comparison Cytology Program with the frequency of misclassification as non- small cell carcinoma. DESIGN: We reviewed 1185 interpretations of 23 different cases of small cell carcinoma in lung fine-needle aspiration specimens and correlated the cytologic features noted in these cases with performance in the program. RESULTS: Cases were divided into those that were frequently misclassified as non-small cell carcinoma (at least 10% of the responses, 11 cases) and those that were infrequently misclassified as non-small cell carcinoma (<5% of all responses, 12 cases). All cases had areas on the slides with classic features of small cell carcinoma. However, 10 of 11 cases that were frequently misclassified as non-small cell carcinoma had cells with either increased cytoplasm (4 cases), cytoplasmic globules (so-called paranuclear blue bodies) (3 cases), or apparent intracytoplasmic lumina (3 cases). These features were not identified in cases that were infrequently misclassified (P = .005). In addition, cases more frequently misclassified as non-small cell carcinoma tended to show better overall cellular and group preservation. CONCLUSIONS: Frequent misclassification of small cell carcinoma as non-small cell carcinoma in lung fine-needle aspiration specimens in this program correlates strongly with the presence of cytoplasmic features that may suggest non-small cell carcinoma or with the presence of paranuclear blue bodies. Misclassification in this program may reflect a variety of factors, including the variation in the cytologic features of individual cases, but also the lack of wide recognition that some features of non-small cell carcinoma may also be noted in well-preserved cases of small cell carcinoma.

Biopsy, Fine-Needle↗

Fine-needle aspirates of adenocarcinoma/metastatic carcinoma that resemble hepatocellular carcinoma: correlating cytologic features and performance in the College of American Pathologists Nongynecologic Cytology Program.

CONTEXT: The cytologic features of adenocarcinoma/ metastatic carcinoma in liver fine-needle aspirates are well described. We review the cytologic findings from 16 aspirates of adenocarcinoma/metastatic carcinoma that were frequently misclassified as hepatocellular carcinomas and compare them with 17 cases that were rarely misclassified. OBJECTIVE: To compare the cytologic features of adenocarcinoma/metastatic carcinoma in fine-needle aspiration specimens of the liver that were frequently misclassified as hepatocellular carcinoma with those of aspirates that were rarely misclassified. DESIGN: We reviewed a total of 1712 interpretations from 33 different cases of adenocarcinoma/metastatic carcinoma tumor in liver fine-needle aspiration specimens in the College of American Pathologists Nongynecologic Cytology Program and correlated the cytologic features with performance in the program. RESULTS: Overall, cases that were frequently misclassified as hepatocellular carcinoma were misclassified on average 26% of the time (range, 13%-54%), while infrequently misclassified cases were interpreted as hepatocellular carcinoma on average 0.7% of the time (range, 0%-3%). The difference was statistically significant (P < .001). On review, cases that were frequently misclassified most often had moderate amounts of granular cytoplasm (16/16 cases) and round nuclei with even chromatin (13/16 cases). Trabeculae (3/16 cases), bare nuclei (2/16 cases), and endothelial wrapping (1/16 cases) were also occasionally present. In contrast, cases that were rarely misclassified were more likely to have areas with cells showing scant cytoplasm that were crowded and overlapped or molded (13/17 cases) and contained dark hyperchromatic chromatin (13/17 cases) compared to cases that were frequently misclassified (P < .001 and P = .002, respectively). Trabeculae (2/17) and bare nuclei (2/17 cases) were also rarely present. CONCLUSION: Cases of adenocarcinoma/metastatic carcinoma with moderate amounts of granular cytoplasm and round nuclei with even chromatin are frequently misclassified as hepatocellular carcinoma. Recognition of this problem, attention to cytologic criteria, and frequent use of immunohistochemical studies and core biopsy may help avoid this pitfall.

Adenocarcinoma↗

Cytologic features of low-grade squamous intraepithelial lesion in thinprep papanicolaou test slides and conventional smears: comparison of cases that performed poorly with those that performed well in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

CONTEXT: Both conventional and ThinPrep Papanicolaou smears with high-grade squamous intraepithelial lesions that are frequently missed are known to have relatively few abnormal cells. Whether this is also true of cases of low-grade squamous intraepithelial lesion is not known. OBJECTIVE: To compare the cytologic features of cases of low-grade squamous intraepithelial lesion that perform poorly with the features of cases that perform well. DESIGN: The cytologic features of 10 ThinPrep Pap Test and conventional smear cases of low-grade squamous intraepithelial lesion that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 46 ThinPrep Pap Test and conventional smear cases that performed extremely well. The numbers of abnormal cells were categorized into less than 50, 51 to 100, 101 to 250, 251 to 500, and more than 500. RESULTS: The median number of abnormal cells for cases that performed poorly was less than 50, whereas the median number of abnormal cells for cases that performed well was between 101 and 250. Overall, cases that performed poorly were significantly more likely to have less than 50, less than 100, and less than 250 abnormal cells than cases that performed well (P < .001, P < .001, and P = .009, respectively). A minority of cases performed well even with very few abnormal cells and groups. The same findings were present when conventional smears and ThinPrep specimens were analyzed separately. CONCLUSIONS: ThinPrep Pap Test cases and conventional smears with a diagnosis of low-grade squamous intraepithelial lesion that perform poorly in this program have significantly fewer abnormal cells than those that perform well. The median number of abnormal cells in cases that performed well is lower than that of comparable high-grade cases in the program.

Carcinoma, Squamous Cell↗

Distinguishing carcinoid tumor of the mediastinum from thymoma: correlating cytologic features and performance in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytopathology.

CONTEXT: The cytologic features of carcinoid tumor in mediastinal fine-needle aspiration are well described. Nevertheless, this tumor may be difficult to distinguish from thymoma in this site. OBJECTIVE: We sought to correlate the cytologic features of carcinoid tumor of the mediastinum in the College of American Pathologists Interlaboratory Comparison Program in Nongynecologic Cytopathology with the frequency of misclassification as thymoma. DESIGN: We reviewed 446 interpretations from 18 different cases of carcinoid tumor in mediastinum and correlated the cytologic features with performance. RESULTS: Cases were more frequently classified as thymoma (158 responses, 35%) than as carcinoid tumor (126 responses, 28%). The best-performing case was classified as carcinoid tumor only 56% of the time. Three cytologic patterns were identified. Four cases consisted of isolated round cells with salt-and-pepper chromatin. Four cases consisted of isolated spindle and round cells with salt-and-pepper chromatin. The remaining 10 cases consisted of cohesive fragments of crowded cells with finely granular chromatin showing numerous pyknotic cells mimicking lymphocytes. Prominent vasculature patterns were not a feature of any of the cases. There was no correlation between any pattern and the rate of classification as carcinoid tumor or thymoma (P > .05). CONCLUSIONS: Carcinoid tumor of the mediastinum is frequently misclassified as thymoma in this program. Although some cytologic patterns resemble thymoma, the lack of correlation of these patterns with performance suggests that at least part of the reason for misclassification may be failure to consider the correct diagnosis or a lack of familiarity with discriminating cytologic criteria.

Biopsy, Fine-Needle↗

Leukemia/lymphoma in cerebrospinal fluid: distinguishing between cases that performed well and poorly in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology.

CONTEXT: Although the cytologic features of leukemia/lymphoma in cerebrospinal fluid specimens are well known, the correlation of these features with the ability of cytologists to identify this tumor have not been well studied. OBJECTIVE: To identify the morphologic features of leukemia/lymphoma in cerebrospinal fluid that are associated with good performance and poor performance in an educational interlaboratory comparison program; and to identify the morphologic features associated with how well a slide performs with regard to its reference diagnosis. DESIGN: The performance of 147 cases of leukemia/lymphoma in the College of American Pathologists Interlaboratory Comparison Program in Non-gynecologic Cytology was analyzed. The cytologic features of a subset of 31 cases composed of relatively equal numbers of Romanowsky-stained and Papanicolaou-stained specimens were further evaluated, and those that performed poorly (n = 12) were compared with those that performed extremely well (n = 19). RESULTS: For all cases of leukemia/lymphoma in the program, the rate of misclassification as benign for cases with Papanicolaou stain was significantly higher than for those with Romanowsky stain (9.5% vs 2.6%, P < .001). Compared with cases that performed well, slides that performed poorly were more likely to have less than 200 abnormal cells (42% vs 5%, P = .02). The size of the tumor cells and preservation were not significant. CONCLUSION: Cases of specimens of leukemia/lymphoma in cerebrospinal fluid are more likely to be misdiagnosed as benign if they are Papanicolaou-stained or have 200 abnormal cells.

Cytodiagnosis↗