In this study, we evaluated the performance of a recently developed immunoassay analyser, the VISTA 500 (Siemens, Germany). Precision, linearity, and comparison studies were performed according to the Clinical and Laboratory Standards Institute guidelines. The test items evaluated included IgG, IgA, IgM, C3, C4, ceruloplasmin, prealbumin, transferrin, haptoglobin, rheumatoid factor, anti-streptolysin O, and cystatin C. Commercial control materials (BioRad Laboratories, USA), commercial linearity validation materials (Maine Standards, USA), and patient samples were used for the evaluation. For the correlation study, analysis with a BN-II nephelometer (Siemens) was used as a comparative method. Total coefficients of variation of analytes were found to be between 1.9% and 5.5%. Results of the linearity evaluation were also acceptable for the range tested. Correlations with comparative methods were acceptable. The VISTA 500 analyser showed satisfactory analytical performance with respect to precision, linearity, and comparison. We conclude that the VISTA 500 is likely a good candidate as an immunology analyser.
Allergy and Immunology ; Ceruloplasmin ; Cystatin C ; Evaluation Studies as Topic ; Haptoglobins ; Humans ; Immunoassay ; Immunoglobulin A ; Immunoglobulin G ; Immunoglobulin M ; Prealbumin ; Rheumatoid Factor ; Statistics as Topic ; Transferrin

BACKGROUND: External quality assessment (EQA) uses a standard deviation index (SDI), based on a peer group, to evaluate laboratory performance. However, evaluations using peer group SDIs often have limited applicability, because they are not statistically valid unless the number of institutions in the same peer group is large. The present study proposes a statistical model for simultaneously evaluating the performance of all participating institutions, as well as the performance of instruments on the market. METHODS: By assuming that proficiency test results were affected by the manufacturer, the instrument, and the institution, the effects of those factors were estimated using a linear mixed model. We used these effect estimates to calculate manufacturer, instrument, and institution SDIs. Using simulation, we evaluated the false positive rates and efficiencies of the proposed linear mixed model. RESULTS: Simulations showed that the linear mixed model empirical type I error rates preserved the nominal significance level. This model was also more statistically efficient than the peer group SDI. Rates of unacceptability were lower when using institution SDI than they were when using peer group SDI. Additional outliers that could not be evaluated using the current system were detected by the institution SDI statistic. The instrument SDI statistic detected outliers among different instrument groups. CONCLUSIONS: Institution and instrument SDIs are robust and efficient tools for EQA, and they can replace the currently used system of peer group SDI.
Laboratory Proficiency Testing ; Models, Statistical ; Peer Group

The Diagnostic Genetics Subcommittee of Korean Association of External Quality Assessment Service conducted two trials in 2015 based on cytogenetics and molecular genetics surveys. A total of 43 laboratories participated in the chromosome surveys, 31 laboratories participated in the fluorescence in situ hybridization surveys, and 133 laboratories participated in the molecular genetics surveys. All except one laboratory showed acceptable results in the cytogenetics surveys. The molecular genetics surveys included the following tests: Mycobacterium tuberculosis detection, hepatitis B and C virus detection and quantification, human papilloma virus genotyping, gene rearrangement tests for leukaemias and lymphomas, genetic tests for JAK2, FMS-like tyrosine kinase 3, nucleophosmin, cancer-associated genes (KRAS, EGFR, KIT, and BRAF), hereditary breast and ovarian cancer genes (BRCA1 and BRCA2), Li-Fraumeni syndrome (TP53), Wilson disease (ATP7B), achondroplasia (FGFR3), hearing loss and deafness (GJB2 ), multiple endocrine neoplasia 2 (RET), Huntington disease, spinocerebellar ataxia, spinal and bulbar muscular atrophy, mitochondrial encephalopathy with lactic acidosis and stroke like episodes, myoclonic epilepsy ragged red fibre, Leber hereditary optic neuropathy, Prader-Willi/Angelman syndrome, Duchenne muscular dystrophy, spinal muscular atrophy, fragile X syndrome (FMR1), apolipoprotein E genotyping, methylenetetrahydrofolate reductase genotyping, ABO genotyping, cytochrome P450 2C9 genotyping, cytochrome P450 2C19 genotyping, and DNA sequencing analysis. The molecular genetics surveys showed excellent results for most of the participants. The external quality assessment program for genetics analysis in 2015 proved to be helpful for continuous education and the evaluation of quality improvement.
Achondroplasia ; Acidosis, Lactic ; Apolipoproteins ; Breast ; Cytochrome P-450 Enzyme System ; Cytogenetics ; Deafness ; Education ; Epilepsies, Myoclonic ; Fluorescence ; fms-Like Tyrosine Kinase 3 ; Fragile X Syndrome ; Gene Rearrangement ; Genetics* ; Hearing Loss ; Hepatitis B ; Hepatolenticular Degeneration ; Humans ; Huntington Disease ; In Situ Hybridization ; Korea* ; Li-Fraumeni Syndrome ; Lymphoma ; Methylenetetrahydrofolate Reductase (NADPH2) ; Molecular Biology ; Multiple Endocrine Neoplasia ; Muscular Atrophy, Spinal ; Muscular Disorders, Atrophic ; Muscular Dystrophy, Duchenne ; Mycobacterium tuberculosis ; Optic Atrophy, Hereditary, Leber ; Ovarian Neoplasms ; Papilloma ; Quality Improvement ; Sequence Analysis, DNA ; Spinocerebellar Ataxias ; Stroke

As an annual function of the Therapeutic Drug Monitoring Subcommittee of Korean Association of External Quality Assessment Service (K-EQAS), we organised two trials for an external quality assessment of therapeutic drug monitoring (TDM) and testing for drugs of abuse (DOA) in 2015. For the TDM assessment, we sent low- and high-level control materials from various clinical institutions, and for the DOA testing, we sent positive and negative control materials. The number of participating laboratories was 105 for the TDM trial and 106 for the DOA test. The average number of drug items provided was 5.6 per institution. The most commonly tested substances, in descending order, were: valproic acid, digoxin, vancomycin, tacrolimus, and carbamazepine. The mean inter-laboratory coefficients of variation for low- and high-level TDM control materials were 7.3% and 7.4%, respectively. The most widely used TDM analysers were the Architect i System (Abbott Diagnostics, USA), followed by the Cobas Integra (Roche Diagnostics, Switzerland) and the Cobas c501 analyser (Roche Diagnostics). The number of participating laboratories for the DOA analysis was 16% higher that than of our 2014 study. In 98.6% of cases, our analysis confirmed the reliabilityviability of the tests at participating DOA laboratories in both trials. In the external quality assessment of TDM by the TDM subcommittee of K-EQAS in 2015, the overall performance of TDM testing was found to be similar to that reported in previous years, and inter-laboratory precision was higher than that of 2014. Continuous improvement in the quality of TDM testing through participation in a proficiency-testing program will remain necessary in the future.
Carbamazepine ; Digoxin ; Drug Monitoring* ; Korea* ; Laboratory Proficiency Testing ; Street Drugs* ; Tacrolimus ; Valproic Acid ; Vancomycin

During 2015, the Diagnostic Hematology Subcommittee of Korean Association of External Quality Assessment Service performed laboratory proficiency testing for blood cell count, cell morphology, and coagulation tests. Four trials for blood cell count and cell morphology tests each and two trials for coagulation tests were performed. The trials for blood cell counts had a reply rate of 97.2% among 1,352 laboratories, compared to 99.0% among 503 laboratories for cell morphology and 98.6% among 574 laboratories for coagulation tests. The homogeneity of the external quality materials was stable (<3%), and the use of instruments and reagents was similar to that observed during the previous year. The coefficients of variation (CVs) for white blood cell counts, red blood cell counts, platelet counts, hemoglobin tests, and hematocrit tests were 4.13%, 1.89%, 1.92%, 5.02%, and 8.10%, respectively. For cell morphology tests, concordant rates were >80% for most of the participating laboratories. The CVs for the coagulation tests varied according to the specific instruments or reagents that were used. An educational workshop was held in November to provide hands-on experience in diagnostic hematology. During 2015, the number of participating laboratories increased, while the performance of hematology tests was similar to that observed in the previous year.
Blood Cell Count ; Education ; Erythrocyte Count ; Hematocrit ; Hematology* ; Indicators and Reagents ; Korea* ; Laboratory Proficiency Testing ; Leukocyte Count ; Partial Thromboplastin Time ; Platelet Count ; Prothrombin Time

BACKGROUND: Detection of antiphospholipid antibodies (aPL) can be considered problematic due to assay variability and reagent sensitivity, high false-positive and false-negative rates, and lack of assay standardization. Therefore, utilizing an automated system can improve reproducibility and reduce interlaboratory variation. Here, we evaluated the analytical performance of the new automated ACL AcuStar chemiluminescence assay (Instrumentation Laboratory, USA). This was compared to the results of a panel analyzed with the QUANTA Lite ELISA (INOVA Diagnostics Inc., USA). METHODS: We evaluated the inter-assay precision, linearity, and carry-over between the two methods, ACL and ELISA. A reference range study for each of the anticardiolipin (aCL) and anti-beta2 glycoprotein-I (abeta2GPI) IgG and IgM antibodies were performed using 135 healthy patient samples, which served as controls. We then compared the accuracy among the AcuStar and ELISA systems via four aPL tests. For this comparison, 69 patient samples suspected of an autoimmune disorder were used as the experimental panel. RESULTS: The AcuStar analyzer showed excellent precision, linearity, and carry-over for all four assays. The calculated cutoff values were 20.3 U/mL for aCL IgG, 20.3 U/mL for aCL IgM, 26.3 U/mL for abeta2GPI IgG, and 11.9 U/mL for abeta2GPI IgM. The consensus between AcuStar and ELISA results were generally comparable. Total agreement varied between 82.6% and 95.7%, and kappa values showed moderate to good agreement. CONCLUSIONS: Our study demonstrates that the new AcuStar chemiluminescence assay showed better performance. This automated system leads to improved reproducibility and reduces interlaboratory variability.
Antibodies ; Antibodies, Anticardiolipin ; Antibodies, Antiphospholipid* ; Antiphospholipid Syndrome ; Automation ; Consensus ; Enzyme-Linked Immunosorbent Assay ; Humans ; Immunoglobulin G ; Immunoglobulin M ; Luminescence* ; Reference Values

As Immunoserology Subcommittee of the Korean Association of External Quality Assessment Service, we organized two trials on the external quality assessment of viral markers and serological tests for syphilis (STS) in 2014. For this purpose, we delivered three kinds of pooled sera specimens for external proficiency testing to 1,060 and 1,064 institutions for the first and second trials, respectively. Pooled sera were checked for their homogeneity and stability by using more than three other methods between the day of their manufacture and 3 days after despatching. The numbers of participating laboratories were 1,053 (99.3%) and 1,046 (99.3%) in the first and second trials, respectively. The most commonly tested items were hepatitis B surface antigen, followed by antibody to hepatitis B surface antigen, anti-human immunodeficiency virus, anti-hepatitis C virus, STS, and anti-hepatitis B core. The most frequently used methods for detecting viral markers were the chemiluminescence immunoassay (CLIA) and the electrochemiluminescence immunoassay, which generated few false positive results. In contrast, false negative results were frequently found through the immunochromatography assay, the use of which for detecting viral markers has been steadily increasing in recent years. Furthermore, the use of turbidoimmunoassay and CLIA, which are new tests recently introduced for the measurement of non-treponemal and treponemal antibodies, is also increasing.
Antibodies ; Biomarkers* ; Hepatitis B ; Hepatitis B Surface Antigens ; Hepatitis C ; HIV ; Immunoassay ; Immunochromatography ; Korea* ; Laboratory Proficiency Testing ; Luminescence ; Serologic Tests* ; Syphilis*

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.
Alkaline Phosphatase ; Bilirubin ; Blood Urea Nitrogen ; Calcium ; Carbon Dioxide ; Chemistry ; Chemistry, Clinical* ; Cholesterol ; Cholesterol, HDL ; Cholesterol, LDL ; Clinical Chemistry Tests ; Creatinine ; Glucose ; Hydrogen-Ion Concentration ; Korea* ; L-Lactate Dehydrogenase ; Laboratory Proficiency Testing ; Oxygen ; Partial Pressure ; Peer Group ; Phosphorus ; Potassium ; Research Report ; Sodium ; Transferases ; Triglycerides ; Uric Acid

BACKGROUND: For the efficient management of clinical pathology laboratory, not only the economic side but also the quality of test should be considered. Therefore, the authors investigated the status of laboratory in the management point including the status of technical personnel by survey and tried to find out the fundamental status of work environment, laboratory automation, computerization, and to evaluate the efficiency of management of clinical pathology laboratories in Korea. METHOD: The questionnaires included those for investigating laboratory management status, qualities of laboratory personnels, workloads, test items and numbers of tests performed annually. It contained 22 items with 32 detailed sub-questionnaires for laboratory personnel survey, and 9 items with 106 detailed sub-questionnaires for facilities. We sent those three times to 400 laboratories that were participating in the National External Quality Assessment Scheme in Korea and analysed the answers by descriptive statistics, ANOVA, t-test and correlation analysis. RESULTS: The replies were from 96 laboratories and 326 technical personnels. Among the 96 laboratories, there were 71 full time employed clinical pathologists. The annually performed number of tests were increased with the increased the size of laboratory, that was classified by number of personnels. As the laboratory size was increased, part time personnels, cases of test per technical personnel, automation and computerization, satisfaction for their work (58,2%) were increased but decreased satisfaction of salaries. CONCLUSIONS: We surveyed the present employee status of laboratory personnels and status of laboratory and offered fundamental data of clinical laboratory management in Korea.
Automation ; Automation, Laboratory ; Humans ; Korea* ; Laboratory Personnel ; Pathology, Clinical ; Surveys and Questionnaires ; Salaries and Fringe Benefits

BACKGROUND: The occurrence of extended-spectrum beta-lactamases (ESBLs) in enterobacteria that possess inducible Bush group 1 chromosomal beta-lactamases is being increasingly reported worldwide. The current National Committee for Clinical Laboratory Standards documents do not indicate the tests that should be used for the detection of ESBLs in Enterobacteriaceae except Klebsiella spp. and Escherichia coli. We determined the occurrence and detection of ESBL-producing Enterobacteriaceae isolates. METHODS: One hundred fifty-six consecutive, non-repeated isolates of Citrobacter freundii, Enterobacter spp., Proteus spp., and Serratia marcescens were collected. These isolates were performed broth microdilution antimicrobial susceptibility test, Vitek ESBL detection test, and double disk synergy (DDS) test. All the DDS-positive strains were tested PCR amplification of the blaTEM and blaSHV alleles. RESULTS: S. marcescens (27.3%) was the most frequently isolated ESBL producers followed by E. cloacae (23.8%), E. aerogenes (18.2%), C. freundii (13.3%), and P. mirabilis (8.3%). Among the total of 30 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 26 (86.7%) strains. The genotypes of ESBLs were predominently SHV type (10 isolates) followed by others (8 isolates), SHV and TEM (7 isolates), and TEM type (5 isolates). CONCLUSIONS: Our findings indicate that 19.2% of all Enterobacteriaceae except E. coli and Klebsiella spp. tested produced ESBLs. The Vitek ESBL detection test seems to be a useful test to identify ESBL-producing strains of C. freundii, Enterobacter spp., Proteus spp., and S. marcescens isolates.
Alleles ; beta-Lactamases ; Citrobacter freundii* ; Citrobacter* ; Cloaca ; Enterobacter* ; Enterobacteriaceae ; Escherichia coli ; Genotype ; Klebsiella ; Mirabilis ; Polymerase Chain Reaction ; Proteus* ; Serratia marcescens* ; Serratia*