External quality assessment (EQA) of Neisseria gonorrhoeae antimicrobial susceptibility testing in primary laboratories in Germany.

BACKGROUND: Worldwide, an increase in antimicrobial resistance (AMR) of Neisseria gonorrhoeae has been observed. Until now, no protocol for an external quality assessment (EQA) has been available for Germany. The German gonococcal resistance network (GORENET) performed an EQA of primary laboratories in Germany in order to assess quality of antibiotic susceptibility testing, to gain information about laboratory procedures and to assess the impact of these procedures on test results. METHODS: Laboratories assessed drug susceptibility to cefixime, ceftriaxone, azithromycin, penicillin and ciprofloxacin for five N. gonorrhoeae strains, using their standard laboratory protocols. Minimal inhibitory concentrations (MICs) were compared to World Health Organisation (WHO) consensus results (or, if not available, reference laboratory results), while deviation by +/- one doubling dilution was accepted. Data on laboratory procedures were collected via a standardised questionnaire. Generalized linear models and conditional inference trees (CTREE) were used to assess relationships between laboratory procedures and testing outcomes. RESULTS: Twenty-one primary laboratories participated in the EQA in June 2018. 96% of ciprofloxacin MICs were reported within accepted deviations, as well as 88% for cefixime, 85% for ceftriaxone, 79% for penicillin and 70% for azithromycin. The use of interpretation standards and general laboratory procedures like agar base, incubation settings or the use of control strains strongly differed between laboratories. In statistical analysis, incubation time of cultures < 24 h was associated with correct measurements. Additionally, a 5% CO2 concentration was associated with correct results regarding azithromycin compared to 3%. CTREE analysis showed that incubation time, humidity and CO2 concentration had the greatest influence on the average deviation from consensus results. CONCLUSIONS: In conclusion, we report the development of a protocol for N. gonorrhoeae antimicrobial susceptibility testing in Germany. While testing results were in accordance with the expected consensus results in 70-96%, depending on the antibiotic agent, laboratory methodology was heterogeneous and may significantly affect the testing quality. We therefore recommend the development of a standard operating procedure (SOP) for N. gonorrhoeae susceptibility testing in Germany.

[Analytical and clinical guidelines on neonatal bilirubinemia]. / Recommandations analytiques et cliniques pour l'utilisation de la bilirubinémie en néonatalogie.

The SFBC-CNBH-CNRHP "Neonatal bilirubin" working group performed a biological and clinical study on bilirubin use in neonates for reliable diagnosis and appropriate management of neonatal jaundice. A brief report of a national survey on analytical and biological practices in France is shown. The guidelines of the French Society of Neonatology (SFN) founded the decision of phototherapy set up upon an accurate lab measurement of total serum bilirubin. An abacus is proposed with defined thresholds, as a function of neonate lifetime in hours. However, several studies evidenced poor comparability of results obtained with the different available methods. This situation is partly due to the lack of reference materials, especially for high bilirubin concentrations. Clinical consequences might be observed. We present in this paper the results of a national harmonization study to progress on this issue. Beyond the analytical aspects, the clinical consequences of harmonization defects were investigated. Finally, guidelines for clinical laboratories are proposed, to be locally adapted.

[Proficiency Testing Schemes for Food Nutrition Analysis in Japan (2017-2018)].

This paper deals with proficiency testing schemes for food nutrition analysis in Japan. In schemes in 2017 and 2018, 65 and 73 organizations participated, respectively, and more than 70% of the participants were public organizations responsible for a nutrition-labeling compliance test. The food matrices were pork and chicken sausages, and analytes were protein, fat, ash, moisture, carbohydrate, energy, sodium, salt equivalent, calcium (2018 only), and iron (2018 only). The organizations reporting inadequate laboratory values in one or more nutrients for mandatory declaration (energy, protein, fat, carbohydrate, or salt equivalent) were 11 and 15% of all organizations and 9 and 13% of public organizations in the 2017 and 2018 schemes, respectively. The approximate relative standard deviations for proficiency assessment (RSDr) were as follows: protein, 2%; fat, 3%; ash, 2%; moisture, 0.5%; carbohydrate, 9%; energy, 1%; sodium (salt equivalent), 4%; calcium, 7%; and iron, 7%. Notably, the large RSDr value for carbohydrate may cause inconsistency among laboratories in compliance tests for foods containing several grams or less of carbohydrate per 100 grams.

Antifungal susceptibility testing practices in mycology laboratories in France, 2018.

A survey of mycology laboratories for antifungal susceptibility testing (AFST) was undertaken in France in 2018, to better understand the difference in practices between the participating centers and to identify the difficulties they may encounter as well as eventual gaps with published standards and guidelines. The survey captured information from 45 mycology laboratories in France on how they perform AFST (number of strains tested, preferred method, technical and quality aspects, interpretation of the MIC values, reading and interpretation difficulties). Results indicated that 86% of respondents used Etest as AFST method, with a combination of one to seven antifungal agents tested. Most of the participating laboratories used similar technical parameters to perform their AFST method and a large majority used, as recommended, internal and external quality assessments. Almost all the participating mycology laboratories (98%) reported difficulties to interpret the MIC values, especially when no clinical breakpoints are available. The survey highlighted that the current AFST practices in France need homogenization, particularly for MIC reading and interpretation.

Alanine Aminotransferase Results Differ by Analyzer Manufacturer in a National Integrated Health Setting, 2012-2017.

CONTEXT.­: Disease guidelines specify universal alanine aminotransferase (ALT) thresholds for clinical decision-making, yet the effect of variability among ALT analyzers remains unclear. OBJECTIVE.­: To compare ALT results from different analyzers from 2012-2017. DESIGN.­: Veterans Health Administration (VHA) laboratories perform external ALT proficiency testing using standardized College of American Pathologists (CAP) samples in analyzers by 5 manufacturers. In this operational analysis, we evaluated 22 950 ALT values from 80 independent CAP samples tested at 223 laboratories. Using mixed effects modeling, we estimated the association between analyzer manufacturer and CAP outcome, adjusting for manufacturer, facility, and calendar year. We performed subgroup analyses on CAP samples with overall means near clinical guideline-specified thresholds, including less than 50 U/L (n = 10) and less than 35 U/L (n = 5). RESULTS.­: The VHA used Abbott Laboratories (n = 3175; 14%), Beckman Coulter Diagnostics (n = 8723; 38%), Roche Diagnostics (n = 2595; 11%), Siemens Healthineers USA (n = 5713; 25%), and Vitros/Ortho Clinical Diagnostics (n = 2744; 12%) analyzers. The CAP samples (n = 80 samples, n = 22 950 tests) covered a wide range of mean ALT values (21-268 U/L). The average difference in mean ALT value per sample between the highest-reading and lowest-reading manufacturers was 15.4 U/L (SD = 1.8) for the 10 samples with mean ALT less than 50 U/L, and it was 10.4 U/L (SD = 3.6) overall (n = 80). In linear mixed effects modeling, we found statistically significant differences in ALT values between the different manufacturers in each year. CONCLUSIONS.­: We found statistically and clinically meaningful differences between analyzers across the ALT spectrum in each year, including at ALT levels lower than 50 U/L and lower than 35 U/L. Universal ALT thresholds should be avoided as a trigger for clinical action until differences between analyzers can be resolved.

[Discussion on evaluation mode of proficiency testing for heavy metal and harmful element detection in medicines].

This study aims to explore the evaluation model for the proficiency testing of heavy metal and harmful element residues in pharmaceuticals,and to provide reference for the proficiency testing program and proficiency testing result in the field of residue analysis. The proficiency test result of cadmium determination in honeysuckle as an example. The algorithm A,NIQR,and Horwitz function are used to calculate the assigned value and the standard deviation. Z was obtained at the same time. If | Z | ≤2,the result is satisfactory. If 2< | Z | <3,the result is questionable. If | Z | ≥3,the result is unsatisfactory. In addition,the median value is the assigned value,and deviation(D%) is used. If D% is not more than 16%,the result is satisfactory; if D% is more than 16%,the result is unsatisfactory. After analysis,in the results of questionable or dissatisfied laboratories calculated by algorithm A and NIQR,the deviation error of some data is within the scope of the standard. In the results of the satisfactory laboratory evaluated by the Horwitz function,some data deviation errors far exceed the standard range. The evaluation result of the D% meets the requirements. According to heavy metal and harmful element trace analysis methods,this study is the first to apply D% to the evaluation of the detection ability of heavy metals and harmful elements in pharmaceuticals. This method makes the evaluation result more reasonable,and has important reference significance for the evaluation of other proficiency test results.

Discussion on evaluation mode of proficiency testing for heavy metal and harmful element detection in medicines / 中国中药杂志

This study aims to explore the evaluation model for the proficiency testing of heavy metal and harmful element residues in pharmaceuticals,and to provide reference for the proficiency testing program and proficiency testing result in the field of residue analysis. The proficiency test result of cadmium determination in honeysuckle as an example. The algorithm A,NIQR,and Horwitz function are used to calculate the assigned value and the standard deviation. Z was obtained at the same time. If | Z | ≤2,the result is satisfactory. If 2< | Z | <3,the result is questionable. If | Z | ≥3,the result is unsatisfactory. In addition,the median value is the assigned value,and deviation(D%) is used. If D% is not more than 16%,the result is satisfactory; if D% is more than 16%,the result is unsatisfactory. After analysis,in the results of questionable or dissatisfied laboratories calculated by algorithm A and NIQR,the deviation error of some data is within the scope of the standard. In the results of the satisfactory laboratory evaluated by the Horwitz function,some data deviation errors far exceed the standard range. The evaluation result of the D% meets the requirements. According to heavy metal and harmful element trace analysis methods,this study is the first to apply D% to the evaluation of the detection ability of heavy metals and harmful elements in pharmaceuticals. This method makes the evaluation result more reasonable,and has important reference significance for the evaluation of other proficiency test results.

Integrated point-of-care testing (POCT) of HIV, syphilis, malaria and anaemia in antenatal clinics in western Kenya: A longitudinal implementation study.

BACKGROUND: In sub-Saharan Africa, HIV, syphilis, malaria and anaemia are leading preventable causes of adverse pregnancy outcomes. In Kenya, policy states women should be tested for all four conditions (malaria only if febrile) at first antenatal care (ANC) visit. In practice, while HIV screening is conducted, coverage of screening for the others is suboptimal and early pregnancy management of illnesses is compromised. This is particularly evident at rural dispensaries that lack laboratories and have parallel programmes for HIV, reproductive health and malaria, resulting in fractured and inadequate care for women. METHODS: A longitudinal eight-month implementation study integrating point-of-care diagnostic tests for the four conditions into routine ANC was conducted in seven purposively selected dispensaries in western Kenya. Testing proficiency of healthcare workers was observed at initial training and at three monthly intervals thereafter. Adoption of testing was compared using ANC register data 8.5 months before and eight months during the intervention. Fidelity to clinical management guidelines was determined by client exit interviews with success defined as ≥90% adherence. FINDINGS: For first ANC visits at baseline (n = 529), testing rates were unavailable for malaria, low for syphilis (4.3%) and anaemia (27.8%), and near universal for HIV (99%). During intervention, over 95% of first attendees (n = 586) completed four tests and of those tested positive, 70.6% received penicillin or erythromycin for syphilis, 65.5% and 48.3% received cotrimoxazole and antiretrovirals respectively for HIV, and 76.4% received artemether/lumefantrine, quinine or dihydroartemisinin-piperaquine correctly for malaria. Iron and folic supplements were given to nearly 90% of women but often at incorrect doses. CONCLUSIONS: Integrating point-of-care testing into ANC at dispensaries with established HIV testing programmes resulted in a significant increase in testing rates, without disturbing HIV testing rates. While more cases were detected and treated, treatment fidelity still requires strengthening and an integrated monitoring and evaluation system needs to be established.

Using Sigma Quality Control to Verify and Monitor Performance in a Multi-Instrument, Multisite Integrated Health Care Network.

The authors developed a system-wide integrated network of instrumentation and Sigma-based quality control for fundamental chemistry, coagulation, and hematology analysis. The authors have based selection of Westgard rules for run management on a straightforward, Sigma-driven selection process. The network includes multiple hospitals and large regional clinic laboratories. Most hospitals have multiple instruments; overall there are at least four distinct instrument models active from each manufacturer. The authors have measured and monitored Sigma values in this network for more than five years, to verify and validate performance and to provide ongoing justification for rules selection and rules changes when necessary.

High Throughput Analytical Techniques for the Determination and Confirmation of Residues of 653 Multiclass Pesticides and Chemical Pollutants in Tea by GC/MS, GC/MS/MS, and LC/MS/MS: Collaborative Study, First Action 2014.09.

Thirty laboratories from fom North and South America, Europe, and Asia participated in this AOAC collaborative study (15 from China; five from Germany; two each from Italy and the United States; and one each from the Republic of Korea, Canada, Spain, Japan, Belgium, and India). Participants represented government regulatory, commercial testing, university, research institute, and private laboratories. The single-laboratory validated (SLV) tea method was evaluated in the collaborative study to determine the recovery and reproducibility of the method under multilaboratory conditions. Since there were no restrictions regarding the type of analytical instrumentation to use for the analyses, laboratories used a combination of equipment that included GC/MS, GC/MS/MS, and LC/MS/MS instruments from 22 different manufacturers, 21 brands of GC and LC columns, 13 different GC temperature programming profiles, 11 LC gradient elution programs, and six different vendor manufactured SPE cartridges. Even though all the analytical performance parameters for all the 653 compounds had been determined in the SLV study, guidance was obtained from an expert review panel of the AOAC Method-Centric Committee on Pesticide Residues to conduct the multilaboratory collaborative study based on 20 selected compounds that can be analyzed by GC/MS and 20 compounds that can be analyzed by LC/MS/MS. Altogether, 560 samples covering the 40 selected pesticides were analyzed in the study. These samples included green tea and oolong tea samples fortified typically at the European Union maximum residue limit for regulatory guidance and compliance, aged tea samples incurred with 20 pesticides, and green tea and oolong tea samples incurred with five pesticides. The analysis of the 560 samples generated a total of 82 459 test results by the 30 participating laboratories. One laboratory failed to meet the proficiency requirements in the precollaborative study. Therefore, its data submitted for the collaborative study were excluded from further analysis and interpretation. The results presented are therefore the 6638 analytical results obtained from the 29 remaining laboratories, which included 1977 results generated by GC/MS, 1704 results by GC/MS/MS, and 2957 results by LC/MS/MS. It was determined after application of the Grubbs and Dixon tests for outliers to the data sets that there were 65 outlier results from the 1977 GC/MS results (3.3%), 65 outlier results from the 1704 GC/MS/MS results (3.8%), and 57 outlier results out of 2957 LC/MS/MS results (1.9%), representing 0.98, 0.98, and 0.86%, respectively, of the 6638 results generated in the study. Analysis with the AOAC statistical software package also confirmed that the method is rugged, and average recovery, average concentration, RSDr, RSDR, and HorRat values all meet recovery and reproducibility criteria for use in multiple laboratories. The Study Director is recommending this method for adoption as an AOAC First Action Official MethodSM.

Annual Report on the External Quality Assessment Scheme for Clinical Chemistry in Korea (2014)

The Clinical Chemistry subcommittee of The Korean Association of External Quality Assessment Service conducted external quality assessments in 2014. This included general chemistry and blood gas measurements as part of a scheme of six trials, comprising of three samples each. All control materials were sent at the same time. The overall response rates were 93.4% for general chemistry and 90.0% for blood gas. The parameters tested included sodium, potassium, chloride, blood urea nitrogen, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, total cholesterol, triglyceride, AST, ALT, alkaline phosphatase, lactate dehydrogenase, gamma glutamyl transferase, HDL cholesterol, and LDL cholesterol for general chemistry and pH, partial pressure of carbon dioxide, and partial pressure of oxygen for blood gas assessment. Two types of reports were generated, namely, a method summary report including mean, standard deviation, and coefficient of variation, for each test method, as well as a result summary report of each participating laboratory, including mean, standard deviation, number of peer groups, and standard deviation index and variance index scores of each laboratory. The overall quality performance in 2014 was similar to that of previous years and as compared to results from 2013, the inter-laboratory variation was lower. The requisite continual improvement in the quality of clinical chemistry testing can be achieved through participation in similar proficiency testing programs.

Evaluation of a biphasic media assay for pyrazinamide drug susceptibility testing of Mycobacterium tuberculosis.

OBJECTIVES: Pyrazinamide is a key first-line tuberculosis drug. Reliable drug susceptibility testing (DST) data are of clinical importance, but in vitro testing is challenging since the activity of pyrazinamide is pH sensitive. The BACTEC MGIT 960 is considered the principal reference technique, but Wayne's test is an alternative, although it may be difficult to interpret. A further alternative is the use of a biphasic media assay (BMA). The objective of this work was to evaluate the BMA against the MGIT method and with screening of pncA gene mutations. METHODS: Twenty strains were inoculated in tubes containing 2 mL of Löwenstein-Jensen (LJ) medium and 2 mL of semi-solid Kirchner medium with a critical concentration of 66 mg/L pyrazinamide at a pH of 5.2 or 5.5, incubated for 2 weeks and visually read. The results obtained were compared with MGIT 960 and DNA sequencing. RESULTS: Results were obtained in duplicate for 19 strains. One strain failed to grow on two occasions and only one result was available. Reproducibility was 95%. Eleven of the 19 strains were susceptible to pyrazinamide, whereas 7 were resistant. One strain was susceptible initially and pyrazinamide resistant on repeat testing. At pH 5.5, two strains reported as susceptible at pH 5.2 gave resistant results. CONCLUSIONS: The BMA might serve as a reliable low-cost DST alternative for pyrazinamide, particularly in laboratories using locally made solid media for DST. Its major drawback is the time to result. A reliable and affordable test method for the detection of pyrazinamide resistance is needed, especially in settings where multidrug-resistant tuberculosis is increasing. Proficiency testing should be routinely introduced wherever pyrazinamide DST is performed.

Combining the quick, easy, cheap, effective, rugged and safe approach and clean-up by immunoaffinity column for the analysis of 15 mycotoxins by isotope dilution liquid chromatography tandem mass spectrometry.

Optimization and validation of a multi-mycotoxin method by LC-MS/MS is presented. The method covers the EU-regulated mycotoxins (aflatoxins, fumonisins, ochratoxin A, deoxynivalenol, zearalenone, T-2 and HT-2), as well as nivalenol and 3- and 15-acetyldeoxynivalenol for analysis of cereals, cocoa, oil, spices, infant formula, coffee and nuts. The proposed procedure combines two clean-up strategies: First, a generic preparation suitable for all mycotoxins based on the QuEChERS (for quick, easy, cheap, effective, rugged and safe) protocol. Second, a specific clean-up devoted to aflatoxins and ochratoxin A using immunoaffinity column (IAC) clean-up. Positive identification of mycotoxins in matrix was conducted according to the confirmation criteria defined in EU Commission Decision 2002/657/EC while quantification was performed by isotopic dilution using (13)C-labeled mycotoxins as internal standards. Limits of quantification were at or below the maximum levels set in the EC/1886/2006 document for all mycotoxin/matrix combinations under regulation. In particular, the inclusion of an IAC step allowed achieving LOQs as low as 0.05 and 0.25µg/kg in cereals for aflatoxins and ochratoxin A, respectively. Other performance parameters like linearity [(r)(2)>0.99], recovery [71-118%], precision [(RSDr and RSDiR)<33%], and trueness [78-117%] were all compliant with the analytical requirements stipulated in the CEN/TR/16059 document. Method ruggedness was proved by a verification process conducted by another laboratory.

Annual Report on the External Quality Assessment Scheme in Clinical Chemistry in Korea (2013) / 임상검사와정도관리

The Clinical Chemistry subcommittee of the Korean Association for Quality Assurance for Clinical Laboratory conducted external quality assessments in 2013. This included general chemistry and blood gas measurements as part of a scheme of six trials, comprising of three samples each. All control materials were sent at the same time. The overall response rates were 90.8% for general chemistry and 88.0% for blood gas. The parameters tested included sodium, potassium, chloride, blood urea nitrogen, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, total cholesterol, triglyceride, AST, ALT, alkaline phosphatase, lactate dehydrogenase, and gamma glutamyl transferase for general chemistry and pH, pCO2, and pO2 for blood gas assessment. Two types of reports were generated, namely, method summary reports including mean, standard deviation, and coefficient of variation, according to the test method as well as result summary reports of each participating laboratory, including mean, standard deviation and number of peer groups, and standard deviation index and variance index score of each laboratory. The overall quality performance in 2013 was similar to that of previous years, and as compared to results from 2012, the inter-laboratory variation had decreased. The requisite continual improvement in quality of clinical chemistry testing can be achieved through participation in similar proficiency testing programs.

Annual Report on the External Quality Assessment Scheme in Clinical Chemistry in Korea (2013) / 임상검사와정도관리

The Clinical Chemistry subcommittee of the Korean Association for Quality Assurance for Clinical Laboratory conducted external quality assessments in 2013. This included general chemistry and blood gas measurements as part of a scheme of six trials, comprising of three samples each. All control materials were sent at the same time. The overall response rates were 90.8% for general chemistry and 88.0% for blood gas. The parameters tested included sodium, potassium, chloride, blood urea nitrogen, glucose, calcium, phosphorus, uric acid, creatinine, bilirubin, total protein, albumin, total cholesterol, triglyceride, AST, ALT, alkaline phosphatase, lactate dehydrogenase, and gamma glutamyl transferase for general chemistry and pH, pCO2, and pO2 for blood gas assessment. Two types of reports were generated, namely, method summary reports including mean, standard deviation, and coefficient of variation, according to the test method as well as result summary reports of each participating laboratory, including mean, standard deviation and number of peer groups, and standard deviation index and variance index score of each laboratory. The overall quality performance in 2013 was similar to that of previous years, and as compared to results from 2012, the inter-laboratory variation had decreased. The requisite continual improvement in quality of clinical chemistry testing can be achieved through participation in similar proficiency testing programs.

Comet assay in reconstructed 3D human epidermal skin models--investigation of intra- and inter-laboratory reproducibility with coded chemicals.

Reconstructed 3D human epidermal skin models are being used increasingly for safety testing of chemicals. Based on EpiDerm™ tissues, an assay was developed in which the tissues were topically exposed to test chemicals for 3h followed by cell isolation and assessment of DNA damage using the comet assay. Inter-laboratory reproducibility of the 3D skin comet assay was initially demonstrated using two model genotoxic carcinogens, methyl methane sulfonate (MMS) and 4-nitroquinoline-n-oxide, and the results showed good concordance among three different laboratories and with in vivo data. In Phase 2 of the project, intra- and inter-laboratory reproducibility was investigated with five coded compounds with different genotoxicity liability tested at three different laboratories. For the genotoxic carcinogens MMS and N-ethyl-N-nitrosourea, all laboratories reported a dose-related and statistically significant increase (P < 0.05) in DNA damage in every experiment. For the genotoxic carcinogen, 2,4-diaminotoluene, the overall result from all laboratories showed a smaller, but significant genotoxic response (P < 0.05). For cyclohexanone (CHN) (non-genotoxic in vitro and in vivo, and non-carcinogenic), an increase compared to the solvent control acetone was observed only in one laboratory. However, the response was not dose related and CHN was judged negative overall, as was p-nitrophenol (p-NP) (genotoxic in vitro but not in vivo and non-carcinogenic), which was the only compound showing clear cytotoxic effects. For p-NP, significant DNA damage generally occurred only at doses that were substantially cytotoxic (>30% cell loss), and the overall response was comparable in all laboratories despite some differences in doses tested. The results of the collaborative study for the coded compounds were generally reproducible among the laboratories involved and intra-laboratory reproducibility was also good. These data indicate that the comet assay in EpiDerm™ skin models is a promising model for the safety assessment of compounds with a dermal route of exposure.

Proficiency of drug susceptibility testing of Mycobacterium tuberculosis against pyrazinamide: the Swedish experience.

BACKGROUND: Pyrazinamide (PZA) is a key drug in the treatment of tuberculosis (TB), including multidrug-resistant TB. Drug susceptibility testing (DST) of Mycobacterium tuberculosis against PZA is not included in the World Health Organization's yearly proficiency testing. There is an increasing need to establish quality control of PZA DST. OBJECTIVE: To evaluate the performance of PZA DST and to introduce a quality assurance system for the test in Sweden. METHOD: Panels with PZA-susceptible and -resistant isolates were used in three rounds of proficiency testing in all five Swedish clinical TB laboratories and our reference laboratory. All laboratories used the MGIT 960 system. Minimum inhibitory concentrations (MICs) were determined and the pncA gene was sequenced to further characterise the 52 panel strains. RESULTS: Good agreement was seen between the phenotypic PZA DST and pncA sequence data, and MIC determination confirmed high levels of resistance. However, in contrast to other drugs, for which correct proficiency test results were observed, specificity problems occurred for PZA DST in some laboratories. CONCLUSIONS: In Sweden, using panel testing, differences were seen in the proficiency of TB laboratories in correctly identifying PZA susceptibility. Improved results were noted in the third round; PZA has therefore been included in yearly proficiency testing.

First proficiency testing of second-line anti-tuberculosis drug susceptibility testing in 12 provinces of China.

OBJECTIVE: To evaluate the performance of drug susceptibility testing (DST) against the main second-line (SL) anti-tuberculosis drugs in tuberculosis (TB) laboratories in China. METHOD: The supranational TB reference laboratory issued 30 Mycobacterium tuberculosis isolates to the participating laboratories. Each participating laboratory performed DST against kanamycin (KM), amikacin (AMK), capreomycin (CPM) and ofloxacin (OFX) using the proportion method in Löwenstein-Jensen medium per World Health Organization recommendations. Reported results were checked and compared with the judicial results. RESULT: The main performance indicators for the four anti-tuberculosis drugs evaluated (KM, AMK, CPM, OFX) were as follows: accordance rates: 91.62%, 99.16%, 96.93% and 96.37%; reproducibility: 99.16%, 99.16%, 94.96% and 94.12%; specificity: 99.12%, 99.64%, 98.00% and 98.41%; sensitivity: 78.03%, 97.62%, 94.44% and 91.51%. The accordance rates and sensitivity values of the four drugs showed statistically significant differences, while specificities showed no significant differences. CONCLUSION: Eight (66.7%) participating laboratories met the set requirement criteria; however, DST in four (33.3%) laboratories requires greater attention. Of the four drugs tested, the results for KM were lower than those for the other drugs. External quality assessment can lead to effective evaluation of laboratory performance in SL DST.