Microbiology of the food chain - Specific requirements and guidance for proficiency testing by interlaboratory comparison

2019 ◽  
Author(s):  
K. Berk Sönmez ◽  
T. Oytun Kılınç ◽  
İ. Ahmet Yüksel ◽  
Sinem Ön Aktan

The competences of the test and calibration laboratories are provided by two complementary methods. The first of these methods is the on-site audit carried out by the administrative and technical committee established by TURKAK (Turkish Accreditation Institution) according to the requirements of TS EN ISO / IEC 17025 [1]. The other technique is interlaboratory comparison and proficiency testing to evaluate laboratory performance and ensure the quality of results. Investing in the right equipment, training personnel, defining methods, documenting, calculating uncertainty, even performing internal verifications do not guarantee reliability or accuracy. It cannot answer the question of whether we can produce the same results as the same testers in the world. It is necessary to prove that the laboratory can actually produce accurate results externally by going through comparison tests with other national/international laboratories.


2005 ◽  
Vol 129 (8) ◽  
pp. 984-989
Author(s):  
Ira A. Shulman ◽  
Lieta M. Maffei ◽  
Katharine A. Downes

Abstract Context.—Pretransfusion testing of whole blood and red blood cell recipients is regulated by the federal government under the authority of the Clinical Laboratory Improvement Amendments of 1988. Regulated tests include determination of ABO group, Rh D type, antibody detection, antibody identification, and crossmatching. A wide variety of methods and reagents are available for these regulated tests. During 2001–2004, the College of American Pathologists (CAP) Interlaboratory Comparison Program (Proficiency Testing) J-Survey collected data from more than 4000 laboratories regarding their pretransfusion testing practices. Those data are presented in this report. Objective.—To assess current testing practices for ABO grouping, Rh D typing, antibody detection, and crossmatching in North America. Design.—Data collected for the CAP Interlaboratory Comparison Program (Proficiency Testing) J-Survey were analyzed for trends in laboratory testing practice during 2001– 2004. The data were grouped for analysis by peer group (testing method used) for ABO grouping, Rh D typing, antibody detection, and crossmatching and then analyzed. Setting, Patients, or Other Participants.—Subscribers to the CAP Interlaboratory Comparison Program Transfusion Medicine J-Series. Results.—The most common testing schemes used in North America during 2001–2004 are as follows: ABO grouping (most laboratories perform tube testing: 97.6% in 2000 and 91.1% in 2004); Rh D typing (most laboratories perform tube testing: 97.7% in 2001 and 91.1% in 2004); antibody detection (most laboratories perform tube testing: 69.7% in 2001 and 55% in 2004, most frequently with the low ionic strength solution anti-human globulin [AHG] method, 48.3% in 2001 and 39.9% in 2004; as of 2004 slightly more laboratories use the gel AHG method [42%] than the low ionic strength solution AHG tube method); crossmatching for alloimmunized patients (most laboratories perform tube testing using a low ionic strength solution AHG method; 55.8% in 2001 and 47.6% in 2004); and crossmatching for nonalloimmunized patients (tube testing using an immediate spin method; 42% in 2001 and 40.4% in 2004). Conclusions.—Most North American laboratories currently favor tube methods when performing ABO grouping, Rh typing, antibody screening, and crossmatching. However, there has been a significant increase in the use of gel-based methods in recent years, especially for antibody detection and crossmatching. Data collection and data analysis of CAP Interlaboratory Comparison Program Survey results allow for assessment of laboratory proficiency and provide insights into current North American practice trends in pretransfusion compatibility testing.


2006 ◽  
Vol 130 (8) ◽  
pp. 1114-1118 ◽  
Author(s):  
Nancy A. Young ◽  
Ann T. Moriarty ◽  
Molly K. Walsh ◽  
Edward Wang ◽  
David C. Wilbur

Abstract Context.—Current regulatory proficiency testing scoring results in an automatic failure for identifying high-grade squamous intraepithelial lesion (HSIL) as negative. Objective.—The College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology data from January 2004 to April 2005 were analyzed to estimate the percentage of failure based on negative responses for HSIL and validation criteria. Design.—More than 15 000 participants received field-validated and educational slide sets for conventional, ThinPrep, and SurePath modules. Educational sets fulfilled the validation criteria of the Center for Medicare and Medicaid Services, which required the consensus diagnosis of biopsy-proven HSIL (not field-validated) after review by 3 pathologists. The College of American Pathologists field validation required at least 20 responses to the HSIL+ series, with 70% matched to HSIL+ (standard error ≤ 0.05). Minimum regulatory proficiency testing failure estimates were based on incorrect negative responses for the reference category of HSIL. Results.—For both cytotechnologists and pathologists, there was a statistically significant higher failure rate for slides that were not field-validated versus those that were field-validated. In conventional modules, 5.3% of the slides that were not field-validated were called negative, versus 1.2% of the field-validated slides. In all liquid-based preparations, 4.0% of the non–field-validated versus 2.2% field-validated slides were called negative. Pathologists would have failed more often than cytotechnologists for the slides that were not field-validated, whereas there was no statistical difference in failure performance with field-validated slides. Conclusions.—Failures were significantly greater with the slides that were not field-validated for both conventional and liquid-based preparations (ThinPrep only) and have implications for both regulatory proficiency testing and expert legal review. Poor performance of pathologists relative to that of cytotechnologists may reflect a lack of prescreening of slides or scope of practice issues.


2006 ◽  
Vol 130 (8) ◽  
pp. 1119-1122 ◽  
Author(s):  
Andrew A. Renshaw ◽  
Molly K. Walsh ◽  
Barbara Blond ◽  
Ann T. Moriarty ◽  
Dina R. Mody ◽  
...  

Abstract Context.—Field validation of slides used in gynecologic cytology proficiency testing has surfaced as an important issue. Although the precision of diagnoses in peer-reviewed educational programs has been examined, the robustness of the validation criteria for specific types of interpretations used in proficiency testing has not been previously studied. Objective.—To evaluate the robustness of validation criteria for slides entering an educational slide program. Design.—We reviewed the results of the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology and compared the robustness of validation criteria for different reference diagnoses, using a total of 16 948 circulating slides. Results.—Validation criteria could be divided into 2 significantly different groups. The criteria for herpes, Trichomonas, squamous cell carcinoma, and adenocarcinoma were significantly more robust than the diagnoses of unsatisfactory; negative for intraepithelial lesion and malignancy, not otherwise specified; low-grade squamous intraepithelial lesion; and high-grade squamous intraepithelial lesion (P < .001). Conclusions.—The validation criteria used in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology show 2 different levels of robustness or redundancy. These results have implications for the design of fair proficiency tests. Proficiency testing can be designed with the necessary number of reviews needed for slide validation.


2013 ◽  
Vol 137 (8) ◽  
pp. 1043-1046
Author(s):  
Lydia Pleotis Howell ◽  
Teresa M. Darragh ◽  
Rhona J. Souers ◽  
Nicole Thomas ◽  
Ann T. Moriarty

Context.—The College of American Pathologists' Interlaboratory Comparison Program in Gynecologic Cytology has seen an increase in enrollment in liquid-based Papanicolaou test challenges with a decrease for conventional Papanicolaou tests. Trichomonas vaginalis can be difficult to identify in all preparation types. Objectives.—To evaluate 20 years of participant results from the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology for Trichomonas to ascertain whether performance has changed because of the introduction of liquid-based Papanicolaou and proficiency testing. Design.—Concordance rates for the target diagnosis of Trichomonas vaginalis were evaluated for 167 956 participant responses (1990–2010). A nonlinear mixed model was fit with participant type, preparation type, and a 2-level program year (1990–2005 and 2006–2010) reflecting before and after proficiency testing began. A repeated-measures component allowed modeling of the slide-specific performance to ensure that the overall results were not based on the performance of a few slides. Results.—Cytotechnologists had higher concordance with the target diagnosis than did pathologists (89.8% [72 992 of 81 319] versus 83.4% [72 271 of 86 637], P < .001) and better performance for each preparation type (P = .003). Concordance initially dropped after the introduction of proficiency testing (P < .001) for conventional and liquid-based (SurePath) preparations by both participant types, followed by quick, parallel improvement. Conclusions.—Performance is high in the detection of Trichomonas vaginalis in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology. Liquid-based Papanicolaou and proficiency testing minimally affected participant performance. Cytotechnologists performed better over time and across preparation types than did pathologists, although pathologists showed performance results parallel to that of the cytotechnologists. Awareness of the performance differences by pathologists and cytotechnologists, as well as their difference in proficiency among liquid-based techniques, may help ensure accurate results in clinical practice.


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