Proficiency Testing Schemes Research Articles

Pilot Round of Proficiency Testing Scheme for Determination of Main Quality Characteristics of Oil Cake

The new scheme of proficiency testing of laboratories for determination of main quality characteristics of oil cake was developed. In pilot round was determined such quality characteristics as moisture content (I), mass fraction of fat (II) and mass fraction of crude protein (III). The control sample was prepared from the sample of rapeseed oil cake. It was determined that control sample was sufficiently stable and homogeneous. In the round participated 22 laboratories, which used different test methods. The results were processed by the method described in ISO 13528. Based on these calculations as assigned value for characteristics I and III was chosen robust mean value and for characteristic II - mode of results. As standard deviation of proficiency testing for characteristic I was chosen robust standard deviation and for characteristics II and III was chosen value which is predicted by equation of Horwitz-Thompson. It was determined, that for characteristics I and III different test methods gives equivalent results, so some unsatisfactory results of laboratories can be attributed to laboratory bias. For characteristic II clustering of results according to measurement method in observed. It was established, that outdated standard GOST 13496.15-97 gives higher mass fraction of fat compared to other test methods.

Development and trial of a dried tube specimen (DTS) proficiency testing panel for dual HIV/syphilis rapid diagnostic tests

To develop and trial a dried tube specimen (DTS) panel for proficiency testing of dual HIV/syphilis rapid diagnostic tests (RDTs) at clinical sites. DTS panels were prepared using plasma samples with known HIV and syphilis results, to give varying reactivity for syphilis and HIV test lines on RDTs. Laboratory DTS panels were stable for a minimum 4-week period at ambient temperatures with no inter-reader variability of results. Field testing of panels with Standard Diagnostics Bioline HIV/Syphilis duo showed 100% correlation with laboratory results, and excellent mean pair agreement between the two clinical sites (k=1.0). With Chembio Dual Path Platform HIV-Syphilis, there were two false negative results for HIV and syphilis, respectively, at one site; and good mean pair agreement between the two sites (k=0.9). It is feasible and practicable to incorporate DTS panels into a field proficiency testing scheme for dual HIV/syphilis RDTs.

Results from a blind comparison of chloride measurements by accredited laboratories and the implications for enforcing increasingly stringent HCl emission limits in EU legislation

ABSTRACT We report results from a blind comparison of six analytical laboratories ISO/IEC 17025 accredited for the implementation of the analytical element of EN 1911, which involves the quantification of chloride in deionized water collected from HCl emitting industrial processes regulated under the EU’s Industrial Emissions Directive (IED). Both “synthetic” (sodium chloride dissolved in deionized water) and “real” (extracted and collected from a stack simulator facility) samples were prepared across ranges which were equivalent to concentrations in the stack of 0–10 mg·m−3 and 0–60 mg·m−3, respectively. Laboratory measurements of the real samples showed significantly poorer performance than the synthetic, implying that the use of synthetic samples in national proficiency testing schemes may be leading to an overly optimistic view of the uncertainties that can routinely be achieved in measurements of real industrial processes. In addition, at the applicable emission limits (10 mg·m−3 and 3 mg·m−3) and measurement ranges (0–15 mg·m−3 and 0–4.5 mg·m−3) under the IED and more recent BAT Conclusions legislation it was found that of the real samples 22 out of 102 (21.6%) and 28 out of 51 (54.9%), respectively, of the measurements would not comply with the overall uncertainty that at least one national regulator considers as necessary for EN 1911 to be an “effective tool” for the calibration of automated measuring systems (AMSs – process plant operator analyzers providing continuous monitoring of emissions). Hence, it is proposed that at the next revision of EN 1911 the standard should be revised to give the same degree of consideration to the analytical element of the method as the sampling element. Key analytical laboratory uncertainty sources should be identified, numerical uncertainty requirements should be placed on key analytical uncertainty sources, and there should be an overall uncertainty requirement for the analytical element. Implications: The deviations observed between laboratories ISO/IEC 17025 accredited for chloride analysis bring into question the ability of the current version of EN 1911 (the CEN Standard Reference Method for monitoring HCl industrial emissions) to meet the uncertainty requirements associated with emission limits under both the EU’s Industrial Emissions Directive and the increasingly stringent industrial sub-sectors BAT Conclusions legislation. It is proposed that at the next revision of EN 1911 that uncertainty guidance and requirements for the analytical element are added if this measurement method is to continue to be mandated across Europe for ensuring emissions data meet legislative quality requirements.

Metrological Traceability and Uncertainty, and Proficiency Testing Scheme in Clinical Laboratory Testings

Metrological Traceability and Uncertainty, and Proficiency Testing Scheme in Clinical Laboratory Testings

UV-Vis Spectroscopic Characterization of Nanomaterials in Aqueous Media

The physicochemical characterization of nanomaterials (NMs) is often an analytical challenge, due to their small size (at least one dimension in the nanoscale, i.e. 1–100 nm), dynamic nature, and diverse properties. At the same time, reliable and repeatable characterization is paramount to ensure safety and quality in the manufacturing of NM-bearing products. There are several methods available to monitor and achieve reliable measurement of nanoscale-related properties, one example of which is Ultraviolet-Visible Spectroscopy (UV-Vis). This is a well-established, simple, and inexpensive technique that provides non-invasive and fast real-time screening evaluation of NM size, concentration, and aggregation state. Such features make UV-Vis an ideal methodology to assess the proficiency testing schemes (PTS) of a validated standard operating procedure (SOP) intended to evaluate the performance and reproducibility of a characterization method. In this paper, the PTS of six partner laboratories from the H2020 project ACEnano were assessed through an interlaboratory comparison (ILC). Standard gold (Au) colloid suspensions of different sizes (ranging 5–100 nm) were characterized by UV-Vis at the different institutions to develop an implementable and robust protocol for NM size characterization.

UV-Vis Spectroscopic Characterization of Nanomaterials in Aqueous Media.

The physicochemical characterization of nanomaterials (NMs) is often an analytical challenge, due to their small size (at least one dimension in the nanoscale, i.e. 1-100 nm), dynamic nature, and diverse properties. At the same time, reliable and repeatable characterization is paramount to ensure safety and quality in the manufacturing of NM-bearing products. There are several methods available to monitor and achieve reliable measurement of nanoscale-related properties, one example of which is Ultraviolet-Visible Spectroscopy (UV-Vis). This is a well-established, simple, and inexpensive technique that provides non-invasive and fast real-time screening evaluation of NM size, concentration, and aggregation state. Such features make UV-Vis an ideal methodology to assess the proficiency testing schemes (PTS) of a validated standard operating procedure (SOP) intended to evaluate the performance and reproducibility of a characterization method. In this paper, the PTS of six partner laboratories from the H2020 project ACEnano were assessed through an interlaboratory comparison (ILC). Standard gold (Au) colloid suspensions of different sizes (ranging 5-100 nm) were characterized by UV-Vis at the different institutions to develop an implementable and robust protocol for NM size characterization.

Proficiency testing scheme based on ISO/IEC 17043 in Indonesia: Strategy in complying the technical requirements for the proficiency testing providers

Proficiency testing (PT) is conducted by accredited providers to assure the validity of measurements conducted by laboratories. ISO/IEC 17043 is the international standard used to assess the competency of PT providers. It consists of five clauses; scope, normative references, term and definitions, technical requirements, and management requirements. Compliance with the ISO/IEC 17043 has been challenging for PT providers especially for the new PT providers tried to gain accreditation for ISO/IEC 17043. The challenges and benefits for the PT providers on implementing ISO/IEC 17043, especially the technical requirements, are discussed with particular emphasis on the homogeneity and stability testing, statistical design, packaging and distribution of PT samples. This discussion is expected giving enlightenment for the new PT providers in complying with the ISO/IEC 17043.

Overview of Analyses of Purified Pharmaceutical water through Proficiency-testing Schemes Results

Overview of Analyses of Purified Pharmaceutical water through Proficiency-testing Schemes Results

Ensuring the reliability of brominated flame retardant data on food and feed occurrence through harmonised analytical criteria and proficiency testing

The volume of occurrence data on food and animal feed contaminants such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDDs) is slowly increasing as more laboratories develop analytical capability. This data allows an evaluation of current background levels in different countries and regions and is also useful for estimating the health risk through dietary exposure and as evidence for the formulation of future control strategies. Existing data varies in the number of analytes reported and the quality measures applied. In order to ensure reliability and comparability, guidance on analytical criteria such as precision and trueness, limits of quantitation, recovery, positive identification, etc. is provided. These parameters are based on several years of collective experience and allow validation and regular quality control of analysis of individual PBDE congeners and HBCDD stereoisomers. The criteria-based approach also allows laboratories the flexibility to use different analytical methodologies and techniques for generating data. The effectiveness of this approach has been demonstrated by a successful proficiency testing scheme that has been used for a number of years and has attracted an increasing number of participants. The majority of participating laboratories (>80%) have been able to demonstrate performance within the 95% confidence interval (│z-score│≤ 2) and a further 10% of laboratories demonstrated performance with a z-score of (2 <│z-score│< 3). The combined support of these guidance criteria backed by successful proficiency testing will ensure the reliability and comparability of results, in particular, to refine risk assessments and to help the formulation of regulatory policy.

Considerations for future environmental DNA accreditation and proficiency testing schemes

AbstractEnvironmental DNA (eDNA) monitoring has revolutionized the way biodiversity is surveyed and has been proposed as a reliable method to inform management decisions. Recognition of eDNA techniques as reliable tools to inform management and biosecurity require stringent standards to assess sample quality and reliability of results. Laboratories can have their workflows assessed and certified through accreditation and be involved in proficiency testing schemes provided to test the accuracy and precision of molecular methods. Currently, there is only one eDNA‐based proficiency testing scheme designed to test competency of laboratories in amplifying eDNA from the Great Crested Newt, Triturus cristatus (Laurenti, 1768) in water samples. This test, however, is a closed scheme currently run by invitation only to laboratories in the United Kingdom. Given the paucity of eDNA‐based proficiency schemes to ensure high‐quality services, this commentary discusses how future proficiency testing schemes could be designed to assess eDNA sample quality and reliability on detection results for environmental management and biosecurity applications. We discuss the use of tissue‐derived and synthetic oligonucleotides as reference materials, the need for proficiency testing schemes to assess the capacity of analytical facilities to determine sample quality as well as accurately detecting trace eDNA in blind samples and discuss the context in which fit for purpose eDNA testing schemes could be designed. To complement the future development of eDNA proficiency testing schemes, we provide firsthand accounts and lessons learned while developing the current Great Crested Newt eDNA proficiency scheme. Lastly, we highlight current limitations in standardizing rapidly improving eDNA‐based techniques and discuss disadvantages to accreditation and standardization from an Australian‐centered perspective as a means to promote an active debate on the topic of future eDNA accreditation and proficiency testing.

Elimination of SARS-CoV-2 along wastewater and sludge treatment processes

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is shed in the feces of infected people. As a consequence, genomic RNA of the virus can be detected in wastewater. Although the presence of viral RNA does not inform on the infectivity of the virus, this presence of genetic material raised the question of the effectiveness of treatment processes in reducing the virus in wastewater and sludge. In this work, treatment lines of 16 wastewater treatment plants were monitored to evaluate the removal of SARS-CoV-2 RNA in raw, processed waters and sludge, from March to May 2020. Viral RNA copies were enumerated using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) in 5 different laboratories. These laboratories participated in proficiency testing scheme and their results demonstrated the reliability and comparability of the results obtained for each one. SARS-CoV-2 RNA was found in 50.5% of the 101 influent wastewater samples characterized. Positive results were detected more frequently in those regions with a COVID-19 incidence higher than 100 cases per 100,000 inhabitants. Wastewater treatment plants (WWTPs) significantly reduced the occurrence of virus RNA along the water treatment lines. Secondary treatment effluents showed an occurrence of SARS-CoV-2 RNA in 23.3% of the samples and no positive results were found after MBR and chlorination. Non-treated sludge (from primary and secondary treatments) presented a higher occurrence of SARS-CoV-2 RNA than the corresponding water samples, demonstrating the affinity of virus particles for solids. Furthermore, SARS-CoV-2 RNA was detected in treated sludge after thickening and anaerobic digestion, whereas viral RNA was completely eliminated from sludge only when thermal hydrolysis was applied. Finally, co-analysis of SARS-CoV-2 and F-specific RNA bacteriophages was done in the same water and sludge samples in order to investigate the potential use of these bacteriophages as indicators of SARS-CoV-2 fate and reduction along the wastewater treatment.

On normal and log-normal models imposed on results from proficiency tests for genetically modified organisms (GMO).

This work forms a background to the recent discussion about normal and log-normal distributions in the results of proficiency tests for GMO analysis. In order to clear up some common confusions, the paper first covers some basic principles, viz., a comparison of normally and log-normally distributed samples of results at various precisions, and a background to the determination of assigned values and scoring in proficiency tests. Then follows brief discussions on the identification of outliers and the use of 'tests for normality'. In conclusion, there is a broad outline of the steps that may assist a proficiency testing scheme in deciding on a suitable model of dispersion.

Detection of hepatitis C virus and parvovirus B19 in human plasma pools by nucleic-acid amplification techniques – Trends in results of EDQM proficiency testing studies from 2004 to 2018

The European Directorate for the Quality of Medicines & HealthCare (EDQM) has run proficiency testing schemes on the detection of viral contaminants in human plasma pools by nucleic-acid amplification techniques since 1999 for hepatitis C virus and since 2004 for parvovirus B19. A retrospective analysis was performed to assess their impact and identify trends and progress in the results obtained by participating laboratories over a 15-year span, from 2004 to 2018. The results demonstrate that overall performance improved over that time, especially among the regular participants. Participation in these proficiency testing schemes is therefore recommended for all interested control laboratories. This analysis also shows that hepatitis C virus detection now seems well established compared to that of parvovirus B19, which still appears more challenging.

Implementation of GeneXpert MTB/Rif proficiency testing program: A Case of the Uganda national tuberculosis reference laboratory/supranational reference laboratory.

Following the WHO's endorsement of GeneXpert MTB/RIF assay for tuberculosis diagnosis in 2010, Uganda's ministry of health introduced the assay in its laboratory network in 2012. However, assessing the quality of the result produced from this technique is one of its major implementation challenges. To bridge this gap, the National tuberculosis reference laboratory (NTRL) introduced the GeneXpert MTB/RIF proficiency testing (PT) Scheme in 2015. A descriptive cross-sectional study on the GeneXpert PT scheme in Uganda was conducted between 2015 and 2018. Sets of panels each comprising four 1ml cryovial liquid samples were sent out to enrolled participants at preset testing periods. The laboratories' testing accuracies were assessed by comparing their reported results to the expected and participants' consensus results. Percentage scores were assigned and feedback reports were sent back to laboratories. Follow up of sites with unsatisfactory results was done through "on and off-site support". Concurrently, standardization of standard operating procedures (SOPs) and practices to the requirements of the International Organization for Standardization (ISO) 17043:2010 was pursued. Participants gradually increased during the program from 56 in the pilot study to 148 in Round 4 (2018). Continual participation of a particular laboratory yielded an odd of 2.5 [95% confidence interval (CI), 1.22 to 4.34] times greater for achieving a score of above 80% with each new round it participated. The "on and off-site" support supervision documented improved performance of failing laboratories. Records of GeneXpert MTB/RIF PT were used to achieve accreditation to ISO 17043:2010 in 2018. Continued participation in GeneXpert MTB/RIF PT improves testing accuracy of laboratories. Effective implementation of this scheme requires competent human resources, facility and equipment, functional quality management system, and adherence to ISO 17043:2010.

EQA/PT scheme to improve the equivalence of enzymatic results between mutual recognition laboratories in Beijing.

BackgroundTo utilize the external quality assessment (EQA)/proficiency testing (PT) scheme to evaluate the equivalence of different clinical enzymatic measuring systems in Beijing.MethodsThe Beijing Center for Clinical Laboratory (BCCL) distributed three investigation samples to mutual recognition clinical laboratories in Beijing including alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ‐glutamyltransferase (GGT), creatine kinase (CK), and lactate dehydrogenase (LDH). These samples were derived from serum pools with values assigned by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) enzymatic reference measurement procedures (RMPs). Each laboratory performed duplicate tests of the samples. Then, the samples at level 1 were used to recalibrate individual measuring systems for repeating the tests. BCCL collected data for evaluation of their analytical quality.ResultsBefore recalibration, the biases of ALT and AST tests were not traceable to the IFCC RMPs, and the bias pass rates of GGT, CK, and LDH tests were only 51.2%, 55.7%, and 48.6% respectively. After recalibration, the pass rates of ALT, AST, GGT, CK, and LDH increased to 95.1%, 82.9%, 95.1%, 97.1%, and 70.0% respectively. The EQA/PT also showed that after recalibration, more than 95% of laboratories met the optimum level specifications of the biological variation for ALT, AST, GGT, and CK tests and the desirable for LDH tests.ConclusionThe enzymatic tests in Beijing need to be further standardized by category 1 or 2 EQA/PT scheme for mutual recognition between clinical laboratories. The criteria of biological variation are more relevant for determining the equivalence of clinical enzymatic tests.

The mycotoxin proficiency testing schemes organized by Turkish National Food Reference Laboratory between the years 2013 and 2020

The Turkish National Food Reference Laboratory has been organizing mycotoxin proficiency tests since 2013. Matrices were mainly selected from the products that Turkey produces and exports most. Therefore, control of mycotoxin contamination in these products intended for domestic consumption and for export to the European Union (EU) and other countries have a special importance. Laboratory controls are one of the important steps in this control. As an external quality control tool, proficiency tests provide the quality assurance of the laboratory test results. For performance evaluation, standard deviation for proficiency assessment is used to calculate z-scores. According to ISO 13528:2015, the standard deviation for proficiency assessment can be determined by experience with previous rounds of proficiency test. As a result of this study, a fit-for-purpose relative standard deviation of 17 % obtained from reevaluation of the previous proficiency tests can be used to calculate standard deviation for proficiency assessment for performance evaluation.

Concordance with established tests and reproducibility of results obtained with a new single antigen chip array for HLA antibody detection (HISTO SPOT® HLA AB)

The purpose of this study was to analyze performance of a new single antigen chip array system (HISTO SPOT® HLA AB) developed for HLA antibody detection and compare with results obtained using single antigen Luminex-based systems and serum samples from the Eurotransplant external proficiency testing scheme. Results were analysed from 11 independent Eurotransplant laboratories using HISTO SPOT® HLA AB utilising the Eurotransplant external proficiency testing (EPT) sera and these were compared to published results from 67 labs using the Luminex-based technologies. In addition, QC results from different batches of the test were analysed. Generally, concordance of results with the results from the Luminex technique was good. With the Luminex tests more consensus results and more questionable results were found than with the HISTO SPOT® HLA AB test. Within the HISTO SPOT® HLA AB testing group we found a discrepancy rate from the consensus of 2.9% for the EPT sera which is far below the 25% allowed to pass the quality test and only slightly higher than for the Luminex single antigen tests with 1.2%. The average global coefficient of variation (CV) of the mean signal (raw data) for the HISTO SPOT® HLA AB test was 13% which is lower than the values reported for Luminex tests in the literature. The average global CV for the signal/background ratio was higher with 28%. In the present study, the mean signal is the best parameter to compare results between labs and the new HISTO SPOT® HLA AB test is at least as good in terms of signal reproducibility as the Luminex tests. In conclusion, the HISTO SPOT® HLA AB test is a good alternative to be used in addition or instead of the Luminex tests in clinical labs.

Simultaneous quantification of cyclosporin, tacrolimus, sirolimus and everolimus in whole blood by UHPLC-MS/MS for therapeutic drug monitoring.

The aim of this study was to develop and validate a UHPLC-MS/MS assay to quantify cyclosporin (CYC), tacrolimus (TAC), sirolimus (SIR) and everolimus (EVE) in human whole blood for therapeutic drug monitoring. Analytes were extracted from 50 μL human whole blood by protein precipitation. The separation of the drugs was performed on an Acquity UPLC BEH C18 column. Analytes were eluted with a mobile phase consisting of 2 mM ammonium acetate with 0.1% formic acid (v/v) in deionised water and 2 mM ammonium acetate with 0.1% formic acid (v/v) in methanol at a flow rate of 300 μL/min in gradient elution. The method performance was evaluated by analysing patient blood samples and/or external quality control samples [proficiency testing (PT) scheme]. The method was linear from 23.75 to 1094.0, 1.3 to 42.4, 1.3 to 47.0 and 1.2-41.6 μg/mL for CYC, TAC, SIR and EVE, respectively. The within- and between-assay reproducibility results were ˂ 11%. Results from PT and patient sample quantification were comparable to those obtained previously by an in-house validated method using protein precipitation and liquid-liquid extraction. This method showed good analytical performance for quantifying CYC, TAC, SIR and EVE in whole blood over their respective calibration ranges.

Implementation of Precaptured Videos of Thyroid Fine-Needle Aspiration Cytology Specimens for External Quality Control Purposes

Objective: The objective of this study was examine the feasibility of developing a proficiency testing scheme for cytology labs wishing to be accredited according to ISO 15189:2012, by using videos captured by static telecytological applications. Methods: The current study was carried out on 252 adequate specimens of 157 patients, retrospectively selected from the department’s registry. In all cases, surgical excision followed the initial cytological diagnosis. Three diagnostic categories of cytological reports were used. All cases were confirmed by histological diagnosis of surgical specimens. One representative video from each case was transferred via file transfer protocol to password-protected accounts for remote review by 3 independent cytopathologists. In addition to diagnosis, reviewers commented on overall digital video quality. Contributor’s and reviewer’s diagnoses were collected, recorded and statistically evaluated. Results: Statistical evaluation of cytological diagnoses detected no significant difference in diagnostic accuracy between the diagnoses proffered on the basis of precaptured videos and conventional slides. The overall interobserver agreement was ranging from substantial to almost perfect. Conclusions: Videos production by static telecytology applications can be used as an alternative method for cytological diagnosis validation. It is a prompt and valid method for quality assessment and proficiency testing and can be integrated into daily workflow. Pre-captured videos can improve significantly small cytology departments’ quality indices. Precaptured videos can also be used for teleconsultation and second opinion purposes and improve the performance of the already existing static telecytology stations.

The FIRMS Network’s PT scheme: What can be learned about inter-laboratory performance?

Demonstrating comparability of isotope-delta values between different laboratories by participation in inter-laboratory exercises (ILEs) is a vital component of method validation. Since its inception, the Forensic Isotope Ratio Mass Spectrometry (FIRMS) Network has provided non-accredited ILEs to its members. Provision of an accredited proficiency testing (PT) scheme to ISO/IEC 17043:2010 was not possible until the administration of the scheme was outsourced to an accredited PT provider—in this case LGC Standards. LGC’s FIRMS PT scheme has been operating since 2013 and in 2015 it was included in their scope of accreditation to ISO/IEC 17043:2010 and it remains the only such accredited PT for stable isotopic analyses.Each round of the PT scheme contains two materials that are of interest to forensic scientists. Participants report up to four isotope delta values for each material and the results of the PT scheme are interpreted using z- or z′-scores calculated using a standard deviation of performance assessment (SDPA) that was initially derived from the submitted data, but now have fixed values.This paper presents and discusses results for the FIRMS PT scheme, including inter-laboratory comparability over time not just for individual laboratories but also for particular matrices that have been analysed in multiple rounds. The FIRMS PT scheme has also distributed the same physical material as earlier FIRMS ILEs providing a longer-term view. A number of interesting findings are presented highlighting the value of PT participation together with a discussion of the status of forensic bio-element stable isotope ratio analysis in the light of these outcomes.