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To implement a pilot proficiency testing (PT) program in Accra, Ghana, using locally produced PT materials and to explore the relationship between laboratory test costs and laboratory quality in Accra, Ghana. Remnant serum samples from a local laboratory were pooled, aliquoted, and distributed to a convenience sample of 23 laboratories in Accra, Ghana, 2 of which had International Organization for Standardization (ISO) accreditation. One of the ISO-accredited laboratories was designated as the reference/target, and the range for passing was based on international criteria. Test cost, test results, and testing instruments used were compiled. Of the 23 laboratories, 18 submitted results. Total testing costs ranged from 80 to 312 Ghanaian cedi (GH₵) (7-26 USD). Overall accuracy (pass rate) was calculated per laboratory and per analyte. The mean laboratory accuracy was 61% (15%-92%). The pass rate for individual analytes ranged from 18% to 94% (mean, 72%). There was no correlation between test cost and pass rate. The pass rates of clinical laboratories in Accra, Ghana, varied from 15% to 92%, and there was no relationship to test cost. A PT program to objectively evaluate each laboratory's performance is needed. Making the PT material locally, as in this study, is a financially sustainable approach.

This article introduces a dynamic framework for reporting blood alcohol concentration (BAC) by integrating measurement uncertainty and interlaboratory variation. This approach is considered necessary to ensure more consistent decision-making rules when analytical results are used in a legal context. Although these rules have been developed within the Italian context, they are adaptable to other countries as well. Included in the framework are critical challenges stemming from variability in laboratory performance and method uncertainty. Data were collected through a national interlaboratory proficiency program involving up to 50 laboratories since 2017. Robust statistical methods were applied to determine consensus values and combined uncertainties. Laboratories meeting inclusion criteria were classified into four performance tiers (Q1-Q4) based on the quartiles of the guard band (GB) distribution, derived from their own uncertainty values. GB values were used to set standardized decision limits, ensuring that the maximum false positive risk remains within 5 % across all laboratories. Results highlight significant performance discrepancies, with GB values varying widely and leading to fragmented decision limits. By clustering laboratories into quartile groups, the framework reduces fragmentation and harmonizes assessments while at the same time maintaining a transparent, performance-based classification. Additionally, targeted training programs and periodic recalibration of uncertainty and GB values promote continuous improvement and enable laboratories to advance to higher tiers as their performance improves. This approach enhances overall reliability, accuracy, and fairness of BAC assessments, and provides a scientifically rigorous approach to uniform reporting results from forensic laboratories. [Display omitted] •Most nations set statutory BAC limits above which driving is an offence.•Quality assurance is vital when lab results are used in legal contexts.•Proposed model uses interlab data and uncertainty to set reliable decision rules.•Guard band quartiles tier labs ensuring ≤ 5 % BAC false positive rate.•Model transferable to other countries and drugs important in forensic toxicology.

Ensuring the reliability, standardization, and international comparability of antimicrobial resistance (AMR) surveillance data critically depends on the implementation of robust quality assurance frameworks. South Korea established the Korea Global Antimicrobial Resistance Surveillance System (Kor-GLASS), supported by a centralized quality control center (QCC). As Kor-GLASS transitioned from Phase II to Phase III, new bacterial species and antimicrobial agents were incorporated, underscoring the need to evaluate whether quality assurance performance could be sustained during system expansion. We analyzed interlaboratory proficiency testing (IPT) and external quality assessment (EQA) outcomes generated by the QCC between 2020 and 2024, covering Phases II and III of Kor-GLASS. Clinical isolates were collected at participating hospitals and transferred to organism-specialized analysis centers for standardized antimicrobial susceptibility testing (AST), while the QCC independently oversees data quality through IPT and EQA. IPT was conducted by comparing AST results between analysis centers and the QCC using subsets of routine clinical isolates, with acceptance criteria defined as categorical agreement (CA) ≥90% and major error rates <3%. EQA involved quarterly distribution of pre-characterized strains to participating centers. Additional evaluations addressed the performance of newly introduced ceftazidime-avibactam susceptibility testing and interlaboratory validation for spp. Across the study period, overall CA consistently exceeded 97% in IPT, and no EQA failures observed among participating centers. While major errors during Phase II were primarily attributable to AST reading and near-breakpoint discrepancies, their frequency markedly decreased in Phase III following targeted corrective actions and educational interventions. Susceptibility testing for ceftazidime-avibactam showed high concordance between centers, with rare discrepancies limited to near-breakpoint measurements. Interlaboratory validation confirmed acceptable performance for AST of spp., supporting its formal inclusion in Phase III. These findings demonstrate that a centralized, QCC-led quality assurance framework can maintain stable and reliable AMR surveillance performance during periods of system expansion. Beyond routine oversight, coordinated quality assurance activities function as an evidence-based evaluation of how standardized laboratory data are generated and validated, reinforcing their essential role in sustaining the credibility and future development of AMR surveillance systems.

Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies. These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.

Comprehensive genomic profiling (CGP) is increasingly used as a clinical laboratory test and being applied to cancer treatment; however, standardization and external quality assessments (EQA) have not been fully developed. This study performed cost-effective EQA and proficiency tests (PT) for CGP testing among multiple institutions those belong to the EQA working group of Japan Association for Clinical Laboratory Science (JACLS). This study revealed that preanalytical processes, such as derived nucleic acids (NA) extraction from formalin fixed paraffine embedded (FFPE) samples, are critical. First, EQA with extracted DNA from cell lines showed a detection rate of 100% (9 out of 9) in KRAS (c.38G > A; p.G13D), PIK3CA (p.H1047R), and B-Raf proto-oncogene, serine/threonine kinase ( BRAF ) (c.1799 T > A; p.V600E) in cases of > 10% variant allele frequency (VAF). However, BRAF (c.1799 T > A; p.V600E) detection decreased to 67% (6 out of 9) for a VAF of 4.9%. Second, when DNA was extracted from FFPE samples, pathogenic variants and variants with companion diagnostic indications were detected in all 10 participating laboratories. Each variant had < 20% VAFs on average (8.1–19.1%) and wide variability among laboratories was observed (relative standard deviation, 13–60%). Nonetheless, BRAF (c.1798_1799delinsAA; p.V600K) of 8.1% VAF, EGFR (c.2235_2249del; p.E746_A750del) of 9.7% VAF, and EGFR (c.2254_2277del; p.S752_I759del) of 9.8% VAF were detected with 70% (7/10), 70% (7/10), and 60% (6/10) frequency, respectively. Therefore, 10% VAF in pre-analytic processing for DNA extraction from FFPE was critical for variant detection in CGP analysis. Further, incorrect results were reported in case independent variant calling of BRAF; c.1798_1799delinsAA (p.V600K) was mistakenly interpreted as c.1798G > A, and c.1799 T > A was on the other strand. In conclusion, the EQA/PT among 10 institutes with common samples revealed the importance of VAF in pre-analysis and helped us understand the significance of the pipeline and common pitfalls usually ignored by the internal quality control in a single institute.

Abstract Objectives To assess the implementation of proficiency testing in the northwest Ethiopian government comprehensive specialized hospital laboratories, with a focus on identifying and understanding the challenges encountered during their participation in the external quality assessment scheme. Methods A cross-sectional study was conducted among 3 comprehensive specialized hospitals in northwest Ethiopia, analyzing 41 documented laboratory test parameters from 2020 to 2022. In addition, face-to-face, in-depth interviews were carried out to identify the major challenges the participating institutions faced. Results The study covered a total of 41 tests across 9 cycles. Overall, proper implementation of proficiency testing was observed in 59.3% of the tests, with 61.8% maintaining consistent implementation status over 3 consecutive years. In addition, the overall performance of the laboratory was 54.3%, with a 68.7% participation rate. The predominantly identified challenges included the lack of participation, insufficient reagents and supplies, inadequacy of suitable proficiency testing materials, equipment malfunction and downtime, lack of management support, insufficient budget, and inadequate training and awareness. Conclusions The results of this study highlight the ineffective implementation of proficiency testing. Contributing factors include personnel issues, equipment and supplies challenges, managerial shortcomings, difficulties with proficiency testing providers, budgetary constraints, and a lack of training and motivation.

Background In 2022, our team launched the pioneering national proficiency testing (PT) scheme for the pathological diagnosis of breast cancer, rapidly establishing its credibility throughout China. Aiming to continuously monitor and improve the proficiency of Chinese pathologists in breast pathology, the second round of the PT scheme was initiated in 2023, which will expand the number of participating institutions, and will conduct a nationwide investigation into the interpretation of HER2 0, 1+, and 2+/FISH- categories in China. Methods The methodology employed in the current round of PT scheme closely mirrors that of the preceding cycle in 2022, which is designed and implemented according to the “Conformity assessment—General requirements for proficiency testing”(GB/T27043—2012/ISO/IEC 17043:2010). More importantly, we utilized a statistics-based method to generate assigned values to enhance their robustness and credibility. Results The final PT results, published on the website of the National Quality Control Center for Cancer ( http://117.133.40.88:3927 ), showed that all participants passed the testing. However, a few institutions demonstrated systemic biases in scoring HER2 0, 1+, and 2+/FISH- with accuracy levels below 59%, considered unsatisfactory. Especially, the concordance rate for HER2 0 cases was only 78.1%, indicating challenges in distinguishing HER2 0 from low HER2 expression. Meanwhile, areas for histologic type and grade interpretation improvement were also noted. Conclusions Our PT scheme demonstrated high proficiency in diagnosing breast cancer in China. But it also identified systemic biases in scoring HER2 0, 1+, and 2+/FISH- at some institutions. More importantly, our study highlighted challenges in the evaluation at the extreme lower end of the HER2 staining spectrum, a crucial area for further research. Meanwhile, it also revealed the need for improvements in interpreting histologic types and grades. These findings strengthened the importance of robust quality assurance mechanisms, like the nationwide PT scheme conducted in this study, to maintain high diagnostic standards and identify areas requiring further training and enhancement.

Abstract Background Proficiency testing (PT) should identify systematic errors, which are likely to recur. The Clinical Laboratory Improvement Amendments of 1988 (CLIA) acceptance limits (ALs) include 3 standard deviations (3SD) and concentration limits. We investigated the ability of PT to detect systematic error, especially as affected by the different AL types. Methods We removed any ungradable, duplicate, and irregular scores from CLIA laboratory PT data from 2008 to 2018. We calculated the overall miss rate, unsatisfactory event rate, i.e., score <80 (4 of 5 correct), and event rates for score 100 to 0. We used paired t-tests and the Wilcoxon signed-rank test to compare miss rates and unsatisfactory event rates between short- and long-term PT participants. We used the binomial distribution to estimate the expected event scores under the assumption that all misses were independent (random). We compared observed event scores with their expected values as a ratio. Results Forty thousand five hundred ninety-six laboratories produced 15 140 128 event scores for 75 analytes. The distribution of event scores was skewed toward multiple event misses (score 0–60) compared to the predicted distribution. Miss rates and unsatisfactory rates were significantly higher for short-term laboratories. Plotting the log ratio of observed vs expected rates for event scores showed that the degree of systematic effect was substantial. The magnitude of the effect was less for 3SD ALs. Conclusions In an event, PT misses are often dependent. All ALs detected systematic error. Expressing systematic error using PT data could help to identify and remediate analytical issues.

The results of a 7-year proficiency study involving Italian laboratories measuring blood alcohol concentration (BAC) are reported. Two blood samples spiked with known amounts of ethanol were sent for analysis twice per year to approximately 50 laboratories across Italy. The blood samples were prepared according to ISO standards, which included optimized transport and storage conditions to ensure ethanol stability. Participants completed an online questionnaire detailing their analytical results along with other analytical details, including the use of GC-FID or GC-MS, storage temperature, time between sample delivery and analysis, reference materials, replicate determinations, and volume of blood aliquot. The participants also confirmed whether or not they were accredited and what the measurement uncertainty was for determination of BAC. The results from analysis of 1171 blood samples (after elimination of outliers) were evaluated by calculating z-scores using robust statistical methods. The inter-laboratory standard deviation (SD) increased with blood alcohol concentration (r = 0.94, p < 0.001). Notably, a significant reduction in robust SD was observed between 2017 and 2023 (p = 0.01). The use of matrix-matched certified reference materials gave more accurate results with mean z-scores closer to zero. The choice of analytical method, storage conditions, time delays, and laboratory accreditation did not significantly influence z-scores. This study revealed that regular participation in inter-laboratory proficiency programs did contribute to improving analytical performance. The choice of certified reference material was the principal determinant of the accuracy of the results. [Display omitted] •Results from a 7-year laboratory proficiency survey in Italy are reported.•Twice annually ∼50 labs analyzed two blood samples spiked with ethanol.•Ethanol concentrations in 1171 blood samples were evaluated using robust statistics.•Inter-lab variance increased with ethanol concentration and decreased over time.•Matrix-matched with certified reference standards was key to improving accuracy.

Aim Pathologists are currently supposed to be aware of both domestic and international guidelines for breast cancer diagnosis, but it is unclear how successfully these guidelines have been integrated into routine clinical practice in China. Thus, this national proficiency testing (PT) scheme for breast pathology was set up to conduct a baseline assessment of the diagnostic capability of pathologists in China. Methods This national PT plan is designed and implemented according to the “Conformity assessment—General requirements for proficiency testing” (GB/T27043—2012/ISO/IEC 17043:2010). Five cases of breast cancer with six key items, including histologic type, grade, ER, PR, HER2, and Ki67, were selected for testing among 96 participants. The final PT results were published on the website of the National Quality Control Center for Cancer ( http://117.133.40.88:3927/cn/col22/362 ). Results Our study demonstrated that the median PT score was 89.5 (54–100). Two institutions with scores < 67 were deemed unacceptable. The accuracy of histologic type, ER, PR, HER2, and Ki67 was satisfactory (all > 86%). However, the histologic grade showed low accuracy (74.0%). The unacceptable results mainly included incorrect evaluation of histologic grade (36.7%), inaccurate evaluation of ER/PR/HER2/Ki67 (28.2%), incorrect identification of C-AD as IBC-NST (15.7%), inappropriate use of 1+/2+/3+ rather than staining percentage for ER/PR (6.1%), misclassification of ER/PR < 1% weak expression as positive staining (1.4%), and no evaluation of histologic grade in ILC, MC, and IMC (5.8%). Conclusions our nationwide PT program exhibited a satisfactory baseline assessment of the diagnostic capability of pathologists in China. More importantly, we identify some areas for further improvement.