Reporting and Establishment of Reference Intervals for Antiphospholipid Antibody Immunoassays: A Survey of Participants in the College of American Pathologists Proficiency Testing Program.

CONTEXT.­: Misdiagnosis of antiphospholipid syndrome can occur owing to the wide diversity of antiphospholipid (aPL) assays and a lack of international calibrators and harmonized reference intervals. OBJECTIVE.­: To assess laboratory practices regarding reporting and establishing reference intervals for immunoglobulin (Ig) G/IgM anti-cardiolipin (aCL) and anti-beta-2 glycoprotein I (anti-ß2GPI) assays. DESIGN.­: Supplemental questions related to reporting and establishing reference ranges for aPL assays were sent as part of the Antiphospholipid Antibody (ACL)-B 2019 College of American Pathologists (CAP) proficiency testing survey. The response rate and methods assessment details were determined, as well as qualitative and quantitative results for 3 test samples. RESULTS.­: The number of participants reporting results for IgG aCL (n = 489), IgM aCL (n = 476), IgG anti-ß2GPI (n = 354), and IgM anti-ß2GPI (n = 331) varied by antibody type. The enzyme-linked immunosorbent assay (ELISA) (up to 58.6%, 260 of 444) was the most used method; others included multiplex (from 18.9% to 23.9%), fluorescence enzyme immunoassay (14.4%-17.6%), and chemiluminescence immunoassay (6.5%-9.0%). More respondents reported quantitative than qualitative results and manufacturer cutoff ranges were used by 92.9% and 94.2% of respondents for aCL and anti-ß2GPI, respectively. Despite variation in the use of semiquantitative ranges, qualitative negative/positive reporting of the test samples achieved almost 100% consensus. Qualitative consensus was met in contrast to the wide range of quantitative results obtained for each analyte across different kits. CONCLUSIONS.­: ELISA remains the most used method for detecting aPL antibodies with most laboratories reporting quantitative results based on manufacturers' suggested reference ranges. The categorization of quantitative results as equivocal, weak positive, or positive for responders using kits from the same manufacturer was variable.

PCNEO, a New Proficiency Testing Program for Flow Cytometric Analysis of Plasma Cell Neoplasms From the College of American Pathologists Diagnostic Immunology and Flow Cytometry Committee.

CONTEXT.­: In 2018 the College of American Pathologists Diagnostic Immunology and Flow Cytometry Committee designed and implemented a new plasma cell neoplasia flow cytometry proficiency testing program-PCNEO-to allow clinical flow cytometry laboratories to monitor and assess their performance compared with a peer group. OBJECTIVE.­: To report the results from the first 4 years of the PCNEO program. DESIGN.­: Program participants were sent 2 sets of challenges per year, each including 1 wet challenge and 2 dry challenges, with associated clinical and laboratory findings. The wet challenges were composed of myeloma cell line specimens (with or without dilution in preserved whole blood) for flow cytometric analysis. The dry (paper) challenges were composed of clinical case summaries and images of flow cytometric test results from various flow cytometry laboratories of committee members. RESULTS.­: A total of 116 to 145 laboratories from 17 countries enrolled in the proficiency testing program. For the wet challenges, almost all participants (97%-100%; cumulative, 98.2%) correctly identified the presence of neoplastic plasma cell populations based on flow cytometric analysis of undiluted myeloma cell lines. Slightly fewer participants (89.0%-97.4%; cumulative, 95.2%) correctly identified the presence of neoplastic plasma cell populations based on flow cytometric analysis of diluted myeloma cell lines (10% or 50% dilutions into peripheral blood) intended to better represent a typical clinical sample. There was generally agreement among 80% or more of participants for positive or negative staining for CD38, CD138, CD19, CD20, and surface and cytoplasmic κ and λ light chains. Similarly, 84% to 100% of participants were able to correctly identify the presence of neoplastic plasma cell populations in paper challenges, including the presence of small, neoplastic plasma cell populations (0.01%-5.0% clonal plasma cells), or the presence of nonneoplastic plasma cell populations (correctly identified by 91%-96% of participants). CONCLUSIONS.­: Participant performance in the new proficiency testing program was excellent overall, with the vast majority of participants able to perform flow cytometric analysis and identify neoplastic plasma cell populations, and to identify small plasma cell clones or expanded populations of reactive plasma cells in dry challenge flow cytometry results. This program will allow laboratories to verify the accuracy of their testing program and test interpretations for the assessment of patients suspected of having a plasma cell neoplasm.

Interlaboratory Agreement of Anti-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Serologic Assays in the Expedited College of American Pathologists Proficiency Testing Program.

CONTEXT.­: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a recently emerged, currently pandemic virus, and the etiologic agent of coronavirus disease 2019 (COVID-19). Clinical testing for antibodies to SARS-CoV-2 has rapidly become widespread, but data regarding the interlaboratory performance of these serologic assays are limited. OBJECTIVE.­: To describe the development and initial results of the College of American Pathologists (CAP) SARS-CoV-2 Serology Survey. DESIGN.­: Members from the CAP Microbiology and Diagnostic Immunology and Flow Cytometry Committees formed a working group to support development of a new proficiency testing survey for anti-SARS-CoV-2 antibody assays. Supplemental questions in the survey assessed the state of SARS-CoV-2 serologic testing among participating laboratories as of July 2020. Results were analyzed for agreement by immunoglobulin (Ig) isotype tested, assay manufacturer, and methodology. RESULTS.­: A total of 4125 qualitative results were received from 1110 laboratories participating in the first survey. Qualitative agreement for assays measuring anti-SARS-CoV-2 total antibodies or IgG was greater than 90% for all 3 samples in the survey. Qualitative agreement for IgM and IgA for the negative sample was greater than 95%, but lacked consensus for the other 2 samples. CONCLUSIONS.­: These initial data suggest overall excellent agreement and comparable performance for most qualitative anti-SARS-CoV-2 IgG and total antibody assays across all participating clinical laboratories, regardless of specific target antigen or assay methodology.

Participation in the College of American Pathologists Laboratory Accreditation Program Decreases Variability in B-Lymphoblastic Leukemia and Plasma Cell Myeloma Flow Cytometric Minimal Residual Disease Testing: A Follow-up Survey.

CONTEXT.­: Minimal residual disease (MRD) testing by flow cytometry is ubiquitous in hematolymphoid neoplasm monitoring, especially B-lymphoblastic leukemia (B-ALL), for which it provides predictive information and guides management. Major heterogeneity was identified in 2014. Subsequently, new Flow Cytometry Checklist items required documentation of the sensitivity determination method and required lower level of detection (LLOD) inclusion in final reports. This study assesses Laboratory Accreditation Program (LAP) participation and new checklist items' impact on flow cytometry MRD testing. OBJECTIVES.­: To survey flow cytometry laboratories about MRD testing for B-ALL and plasma cell myeloma. In particular, enumerate the laboratories performing MRD testing, the proportion performing assays with very low LLODs, and implementation of new checklist items. DESIGN.­: Supplemental questions were distributed in the 2017-A mailing to 548 flow cytometry laboratories subscribed to the College of American Pathologists FL3 Proficiency Testing Survey (Flow Cytometry-Immunophenotypic Characterization of Leukemia/Lymphoma). RESULTS.­: The percentage of laboratories performing MRD studies has significantly decreased since 2014. Wide ranges of LLOD and collection event numbers were reported for B-ALL and plasma cell myeloma. Most laboratories determine LLOD by using dilutional studies and include it in final reports; a higher proportion of LAP participants used these practices than nonparticipants. CONCLUSIONS.­: Several MRD testing aspects vary among laboratories receiving FL3 Proficiency Testing materials. After the survey in 2014, new checklist items were implemented. As compared to 2014, fewer laboratories are performing MRD studies. While LLOD remains heterogeneous, a high proportion of LAP subscribers follow the new checklist requirements and, overall, target LLOD recommendations from disease-specific working groups are met.

Long-Term Variability in Immunofluorescence Titer of Antibodies to Nuclear Antigens Observed in Clinical Laboratory Proficiency Testing Surveys.

CONTEXT.­: Presence of antibodies to nuclear antigens (ANAs) above a threshold titer is an important diagnostic feature of several autoimmune diseases, yet titers reported vary between laboratories. Proficiency survey results can help clarify factors contributing to the variability. OBJECTIVE.­: To determine the contribution of HEp-2 ANA kits from different manufacturers to the variation in titers, and assess whether the differences between kits are consistent over the long term. DESIGN.­: HEp-2 ANA titers reported by laboratories participating in the external quality assessment proficiency testing surveys conducted by the College of American Pathologists between 2008 and 2018 were analyzed. The ANA titers reported for each specimen were ranked according to the kits being used by testing laboratories, and the statistical significance of the differences was determined. RESULTS.­: The ANA titer results were strongly influenced by the HEp-2 ANA kit used (P < .001). During the 11 years studied, the rank order of the ANA titer for each kit relative to the other kits was remarkably consistent. The rank of ANA titer for individual ANA patterns observed for each kit was similar to the overall rank of that kit. CONCLUSIONS.­: Variability in ANA titers was strongly associated with the kits used, and the differences between kits were quite consistent during the 11 years studied. Because the variability is not random, it has the potential to be managed by harmonizing kits, which could lead to improved consistency in reporting ANA titers.

Antinuclear Antibodies Testing Method Variability: A Survey of Participants in the College of American Pathologists' Proficiency Testing Program.

OBJECTIVE: This study was conducted to determine the spectrum of laboratory practices in antinuclear antibody (ANA) test target, performance, and result reporting. METHODS: A questionnaire on ANA testing was distributed by the Diagnostic Immunology and Flow Cytometry Committee of the College of American Pathologists (CAP) to laboratories participating in the 2016 CAP ANA proficiency survey. RESULTS: Of 5847 survey kits distributed, 1206 (21%) responded. ANA screening method varied: 55% indirect immunofluorescence assay, 21% ELISA, 12% multibead immunoassay, and 18% other methods. The name of the test indicated the method used in only 32% of laboratories; only 39% stated the method used on the report. Of 644 laboratories, 80% used HEp-2 cell substrate, 18% HEp-2000 (HEp-2 cell line engineered to overexpress SSA antigen, Ro60), and 2% other. Slides were prepared manually (67%) or on an automated platform (33%) and examined by direct microscopy (84%) or images captured by an automated platform (16%). Only 50% reported a positive result at the customary 1:40 dilution. Titer was reported to endpoint routinely by 43%, only upon request by 23%, or never by 35%. Of the laboratories, 8% did not report dual patterns. Of those reporting multiple patterns, 23% did not report a titer with each pattern. CONCLUSION: ANA methodology and practice, and test naming and reporting varies significantly between laboratories. Lack of uniformity in testing and reporting practice and lack of transparency in communicating the testing method may misdirect clinicians in their management of patients.

Screening and Diagnosis of Monoclonal Gammopathies: An International Survey of Laboratory Practice.

CONTEXT: - Serum tests used for the screening and diagnosis of monoclonal gammopathies include serum protein electrophoresis (SPE; agarose gel or capillary zone), immunofixation (IFE) and immunosubtraction capillary electrophoresis, serum free light chains, quantitative immunoglobulins, and heavy/light-chain combinations. Urine protein electrophoresis and urine IFE may also be used to identify Bence-Jones proteinuria. OBJECTIVE: - To assess current laboratory practice for monoclonal gammopathy testing. DESIGN: - In April 2016, a voluntary questionnaire was distributed to 923 laboratories participating in a protein electrophoresis proficiency testing survey. RESULTS: - Seven hundred seventy-four laboratories from 38 countries and regions completed the questionnaire (83.9% response rate; 774 of 923). The majority of participants (68.6%; 520 of 758) used agarose gel electrophoresis as their SPE method, whereas 31.4% (238 of 758) used capillary zone electrophoresis. The most common test approaches used in screening were SPE with reflex to IFE/immunosubtraction capillary electrophoresis (39.3%; 299 of 760); SPE only (19.1%; 145 of 760); SPE and IFE or immunosubtraction capillary electrophoresis (13.9%; 106 of 760); and SPE with IFE, serum free light chain, and quantitative immunoglobulins (11.8%; 90 of 760). Only 39.8% (305 of 767) of laboratories offered panel testing for ordering convenience. Although SPE was used by most laboratories in diagnosing new cases of myeloma, when laboratories reported the primary test used to follow patients with monoclonal gammopathy, only 55.7% (403 of 724) chose SPE, with the next most common selections being IFE (18.9%; 137 of 724), serum free light chain (11.7%; 85 of 724), and immunosubtraction capillary electrophoresis (2.1%; 15 of 724). CONCLUSIONS: - Ordering and testing practices for the screening and diagnosis of monoclonal gammopathy vary widely across laboratories. Improving utilization management and report content, as well as recognition and development of laboratory-directed testing guidelines, may serve to enhance the clinical value of testing.

Professional Practice Evaluation for Pathologists: The Development, Life, and Death of the Evalumetrics Program.

CONTEXT: - In 2008, the Joint Commission (JC) implemented a standard mandating formal monitoring of physician professional performance as part of the process of granting and maintaining practice privileges. OBJECTIVE: - To create a pathology-specific management tool to aid pathologists in constructing a professional practice-monitoring program, thereby meeting the JC mandate. DESIGN: - A total of 105 College of American Pathologists (CAP)-defined metrics were created. Metrics were based on the job descriptions of pathologists' duties in the laboratory, and metric development was aided by experience from the Q-Probes and Q-Tracks programs. The program was offered in a Web-based format, allowing secure data entry, customization of metrics, and central data collection for future benchmarking. RESULTS: - The program was live for 3 years, with 347 pathologists subscribed from 61 practices (median, 4 per institution; range, 1-35). Subscribers used 93 of the CAP-defined metrics and created 109 custom metrics. The median number of CAP-defined metrics used per pathologist was 5 (range, 1-43), and the median custom-defined metrics per pathologist was 2 (range, 1-5). Most frequently, 1 to 3 metrics were monitored (42.7%), with 20% each following 4 to 6 metrics, 5 to 9 metrics, or greater than 10 metrics. Anatomic pathology metrics were used more commonly than clinical pathology metrics. Owing to low registration, the program was discontinued in 2016. CONCLUSIONS: - Through careful vetting of metrics it was possible to develop a pathologist-specific management tool to address the JC mandate. While this initial product failed, valuable metrics were developed and implementation knowledge was gained that may be used to address new regulatory requirements for emerging value-based payment systems.

Prevalence of Traditional and Reverse-Algorithm Syphilis Screening in Laboratory Practice: A Survey of Participants in the College of American Pathologists Syphilis Serology Proficiency Testing Program.

CONTEXT: -Syphilis serology screening in laboratory practice is evolving. Traditionally, the syphilis screening algorithm begins with a nontreponemal immunoassay, which is manually performed by a laboratory technologist. In contrast, the reverse algorithm begins with a treponemal immunoassay, which can be automated. The Centers for Disease Control and Prevention has recognized both approaches, but little is known about the current state of laboratory practice, which could impact test utilization and interpretation. OBJECTIVE: -To assess the current state of laboratory practice for syphilis serologic screening. DESIGN: -In August 2015, a voluntary questionnaire was sent to the 2360 laboratories that subscribe to the College of American Pathologists syphilis serology proficiency survey. RESULTS: -Of the laboratories surveyed, 98% (2316 of 2360) returned the questionnaire, and about 83% (1911 of 2316) responded to at least some questions. Twenty-eight percent (378 of 1364) reported revision of their syphilis screening algorithm within the past 2 years, and 9% (170 of 1905) of laboratories anticipated changing their screening algorithm in the coming year. Sixty-three percent (1205 of 1911) reported using the traditional algorithm, 16% (304 of 1911) reported using the reverse algorithm, and 2.5% (47 of 1911) reported using both algorithms, whereas 9% (169 of 1911) reported not performing a reflex confirmation test. Of those performing the reverse algorithm, 74% (282 of 380) implemented a new testing platform when introducing the new algorithm. CONCLUSION: -The majority of laboratories still perform the traditional algorithm, but a significant minority have implemented the reverse-screening algorithm. Although the nontreponemal immunologic response typically wanes after cure and becomes undetectable, treponemal immunoassays typically remain positive for life, and it is important for laboratorians and clinicians to consider these assay differences when implementing, using, and interpreting serologic syphilis screening algorithms.

Assessing Clinical Laboratory Quality: A College of American Pathologists Q-Probes Study of Prothrombin Time INR Structures, Processes, and Outcomes in 98 Laboratories.

CONTEXT: The anticoagulant warfarin has been identified as the second most frequent drug responsible for serious, disabling, and fatal adverse drug events in the United States, and its effect on blood coagulation is monitored by the laboratory test called international normalized ratio (INR). OBJECTIVE: To determine the presence of INR policies and procedures, INR practices, and completeness and timeliness of reporting critical INR results in participants' clinical laboratories. DESIGN: Participants reviewed their INR policies and procedure requirements, identified their practices by using a questionnaire, and studied completeness of documentation and timeliness of reporting critical value INR results for outpatients and emergency department patients. RESULTS: In 98 participating institutions, the 5 required policies and procedures were in place in 93% to 99% of clinical laboratories. Fifteen options for the allowable variations among duplicate results from different analyzers, 12 different timeliness goals for reporting critical values, and 18 unique critical value limits were used by participants. All required documentation elements were present in 94.8% of 192 reviewed INR validation reports. Critical value INR results were reported within the time frame established by the laboratory for 93.4% of 2604 results, but 1.0% of results were not reported. Although the median laboratories successfully communicated all critical results within their established time frames and had all the required validation elements based in their 2 most recent INR calculations, those participants at the lowest 10th percentile were successful in 80.0% and 85.7% of these requirements, respectively. CONCLUSIONS: Significant opportunities exist for adherence to INR procedural requirements and for practice patterns and timeliness goals for INR critical results' reporting.

Seven Q-Tracks monitors of laboratory quality drive general performance improvement: experience from the College of American Pathologists Q-Tracks program 1999-2011.

CONTEXT: Many production systems employ standardized statistical monitors that measure defect rates and cycle times, as indices of performance quality. Clinical laboratory testing, a system that produces test results, is amenable to such monitoring. OBJECTIVE: To demonstrate patterns in clinical laboratory testing defect rates and cycle time using 7 College of American Pathologists Q-Tracks program monitors. DESIGN: Subscribers measured monthly rates of outpatient order-entry errors, identification band defects, and specimen rejections; median troponin order-to-report cycle times and rates of STAT test receipt-to-report turnaround time outliers; and critical values reporting event defects, and corrected reports. From these submissions Q-Tracks program staff produced quarterly and annual reports. These charted each subscriber's performance relative to other participating laboratories and aggregate and subgroup performance over time, dividing participants into best and median performers and performers with the most room to improve. Each monitor's patterns of change present percentile distributions of subscribers' performance in relation to monitoring durations and numbers of participating subscribers. Changes over time in defect frequencies and the cycle duration quantify effects on performance of monitor participation. RESULTS: All monitors showed significant decreases in defect rates as the 7 monitors ran variously for 6, 6, 7, 11, 12, 13, and 13 years. The most striking decreases occurred among performers who initially had the most room to improve and among subscribers who participated the longest. All 7 monitors registered significant improvement. Participation effects improved between 0.85% and 5.1% per quarter of participation. CONCLUSIONS: Using statistical quality measures, collecting data monthly, and receiving reports quarterly and yearly, subscribers to a comparative monitoring program documented significant decreases in defect rates and shortening of a cycle time for 6 to 13 years in all 7 ongoing clinical laboratory quality monitors.

Twenty-five years of accomplishments of the College of American Pathologists Q-probes program for clinical pathology.

CONTEXT: During the past 25 years, the College of American Pathologists' (CAP) Q-Probes program has been available as a subscription program to teach laboratorians how to improve the quality of clinical laboratory services. OBJECTIVE: To determine the accomplishments of the CAP Q-Probes program. DESIGN: We reviewed Q-Probes participant information, study data and conclusions, author information, and program accomplishments. RESULTS: During this time 117 Q-Probes clinical pathology studies were conducted by 54 authors and coauthors, 42,899 laboratories enrolled from 24 countries, 98 peer-reviewed publications occurred and were cited more than 1600 times, and the studies were featured 59 times in CAP Today. The most frequent studies (19) focused on turnaround times for results or products at specific locations (emergency department, operating room, inpatients, outpatients), specific diseases (acute myocardial infarction, urinary tract), availability for specific events such as morning rounds or surgery, a specific result (positive blood cultures), and a method on how to use data for improvement (stat test outliers). Percentile ranking of study participants with better performance provided benchmarks for each study with attributes statistically defined that influenced improved performance. Other programs, such as an ongoing quality improvement program (Q-Tracks), a laboratory competency assessment program, a pathologist certification program, and an ongoing physician practice evaluation program (Evalumetrics), have been developed from Q-Probes studies. CONCLUSIONS: The CAP's Q-Probes program has made significant contributions to the medical literature and has developed a worldwide reputation for improving the quality of clinical pathology services worldwide.

Fifteen years' experience of a College of American Pathologists program for continuous monitoring and improvement.

CONTEXT: The Q-Tracks program, created in 1999, is a quality monitoring subscription service offered by the College of American Pathologists. OBJECTIVE: To establish benchmarks in quality metrics, monitor changes in performance over time, and identify practice characteristics associated with better performance. DESIGN: The Q-Tracks program provides ongoing study of multiple metrics offered in most laboratory disciplines. The design enables measuring the effects of process changes and comparisons with other participating laboratories. Each laboratory Q-Tracks monitor has a primary quality indicator and additional secondary indicators. RESULTS: To date, 19 Q-Tracks monitors have been offered, with 12 currently active monitors. Q-Tracks are primarily conducted in hospital-based laboratories in the United States, Canada, and 21 other countries. Common to most Q-Tracks monitors is a demonstration of performance improvement by subscribers with long-term participation. This finding was seen in preanalytic, turnaround time, and postanalytic measures. Q-Tracks monitors contribute to the overall demonstration and improvement of laboratory and hospital quality because they address core quality measures for the College of American Pathologists Laboratory Accreditation Program and multiple Joint Commission National Patient Safety Goals. CONCLUSIONS: The Q-Tracks program has established multiple benchmarks in most disciplines of the laboratory and has demonstrated significant performance improvement in benchmarks and individual laboratories over time.

Q-Probes studies in anatomic pathology: quality improvement through targeted benchmarking.

CONTEXT: The Q-Probes program is a peer-comparison quality assurance service offered by the College of American Pathologists that was created in 1989. OBJECTIVE: To establish national benchmarks around a specific quality metric at a specific point in time in anatomic pathology (AP). DESIGN: Q-Probes are based on a voluntary subscription for an individual study. Hospital-based laboratories in the United States, Canada, and 16 other countries have participated. Approximately one-third of all Q-Probes studies address AP metrics. Each Q-Probes study has a primary quality indicator and additional minor indicators. RESULTS: There have been 52 AP Q-Probes studies addressing process-, outcome-, and structure-related quality assurance issues. These Q-Probes studies often represented the first standardized national benchmark for specific metrics in the disciplines of cytopathology, surgical pathology, and autopsy pathology, and as such have been cited more than 1700 times in peer-reviewed literature. The AP Q-Probes studies that have been repeated over time demonstrate improvement in laboratory performance across an international spectrum. CONCLUSIONS: The Q-Probes program has produced important national benchmarks in AP, addressing preanalytic, analytic, and postanalytic factors in the disciplines of cytopathology, surgical pathology, and autopsy pathology. Q-Probes study data have been published, cited, and used in the creation of laboratory accreditation standards and other national guidelines.

Monitoring and ordering practices for human papillomavirus in cervical cytology: findings from the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference working group 5.

CONTEXT: The association of certain types of human papillomavirus with cervical carcinoma is well established. Human papillomavirus testing is now routinely used to screen for cervical carcinoma and precursor lesions of the cervix (cotesting and reflex testing) and these results are considered in patient triage and management. OBJECTIVE: To provide information about current laboratory practices in human papillomavirus testing and consensus best practice statements based on results from the College of American Pathologists' laboratory-based survey funded by the Centers for Disease Control and Prevention. DESIGN: The College of American Pathologists submitted a paper-based survey to 1245 laboratories in the United States. After review of the initial results, follow-up Web-based survey results, and a literature review by an expert working group, consensus best practice statements were constructed by working group members for presentation at a national consensus conference. These best practice statements were discussed and then voted upon by conference participants. RESULTS: A total of 525 laboratories responded to survey questions about human papillomavirus ordering and monitoring practices, whereas 546 responded to the overall survey. In most laboratories (87.6%), the high-risk human papillomavirus test is ordered as a reflex test by providers. A minority of laboratories (11.9%) routinely bundle low- and high-risk human papillomavirus tests. Most laboratories (84.4%) do not limit testing in patients with atypical squamous cells to women older than 20 years. More than half of laboratories (53.3%) monitor human papillomavirus positive rates in Papanicolaou tests with atypical squamous cells of undetermined significance. CONCLUSIONS: It is not appropriate for laboratories to offer low-risk human papillomavirus testing for any clinical circumstance in gynecologic cytology. Laboratories should not order human papillomavirus testing to resolve diagnostic discrepancies. It is a valuable broad measure of laboratory quality to monitor the human papillomavirus-positive rates in Papanicolaou tests with atypical squamous cells.