Evaluation of the UniCel(TM) DxI 800 Immunoassay Analyzer in Measuring Five Tumor Markers

PURPOSE: Tumor marker concentrations in a given specimen measured by different analyzers vary according to assay methods, epitopes for antibodies used, and reagent specificities. Although great effort in quality assessment has been instituted, discrepancies among results from different analyzers are still present. We evaluated the assay performance of the UniCel(TM) DxI 800 automated analyzer in measuring the alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 125, CA 15-3 and CA 19-9 tumor markers. MATERIALS AND METHODS: The linearity and precision performance of the five tumor marker assays were evaluated, and concentrations of the respective markers as measured by DxI were compared to those measured by other conventional analyzers (ADVIA Centaur(TM) and Vitros(TM) ECi) using 200 specimens collected from 100 healthy persons and 100 patients with respective cancers. RESULTS: The linear fits for all five tumor markers were statistically acceptable (F=4648 for AFP, F=15846 for CEA, F=6445 for CA 125, F=2285 for CA 15-3, F=7459 for CA 19-9; p<0.0001 for all). The imprecision of each tumor marker assay was less than 5% coefficient of variation, except for low and high concentrations of AFP. The results from UniCel(TM) DxI 800 were highly correlated with those from other analyzers. CONCLUSION: Our results demonstrate that UniCel(TM) DxI 800 has good linearity and precision performance for the tumor markers assayed in this study. However, there were discrepancies between assaying methods. Efforts to standardize tumor marker assays should be undertaken, and the redetermination of cut-off levels is necessary when developing methods of analyzing tumor markers.

ADIPOQ Gene Variants Associated with Susceptibility to Obesity and Low Serum Adiponectin Levels in Healthy Koreans / 한국역학회지

OBJECTIVES: This study aimed to measure the association between the adiponectin, C1Q and collagen domain-containing (ADIPOQ) gene variants and obesity in Koreans. METHODS: Three single nucleotide polymorphisms located in the ADIPOQ gene were genotyped in a population-based cross-sectional study of 986 healthy Koreans. Three different case-control groups (i.e. G1, G2, and G3) were defined according to body mass index (BMI) and serum adiponectin levels. Allelic and genotypic associations of this gene with obesity were measured using multivariate logistic regression analyses in each group. RESULTS: The G allele of -11377C>G, a polymorphism located in the promoter region of the ADIPOQ gene (odds ratio (OR), 1.48; 95% confidence interval, 1.13-1.94) and most haplotypes including this allele significantly increased the risk for obesity. However, the OR decreased from 3.98 (G1 group) to 2.90 (G2 group) and 2.30 (G3 group) when a less strict definition of obesity was used. Most haplotypes, including this allele, significantly increased the risk of obesity. The statistical evidence from the GG genotype of -11377C>G (OR, 3.98) and the GT/GT diplotype composed of -11377G>C and +45T>G (OR, 5.20) confirmed the contribution of the G allele toward a predisposition for obesity. CONCLUSION: These results suggest the contribution of the ADIPOQ gene toward susceptibility to obesity in healthy Koreans. The high-risk genotypes and haplotypes identified here may provide more information for identifying individuals who are at risk of obesity.

Annual Report on External Quality Assessment in Immunoassay in Korea (2009) / 임상검사와정도관리

Two trials with 15 test items of external quality assessment survey were performed in 2009. The test items were constituted three immunoassay categories, i.e., tumor markers, thyroid hormones and immunoproteins (IgG, IgM, IgA, C3 and C4). Fifteen test items commonly used in clinical laboratories and performed by immunoassay method were surveyed as scheduled. The number of participated laboratory of external quality assessment for Immunoassay Subcommittee were 494 institutions in the first trial survey and 519 institutions in the second survey. All of the fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (Liquimmune(R), Liquid Assayed Immunoassay Control, Microgenics Co, USA) were used for the two trials in 2009 survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 494 and 519 laboratories and the response rate were 97.6% and 98.3% in 2009. 2. Chemiluminiscence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories for detecting tumor markers and hormones. 3. Stability tests of home-made control materials were performed and confirmed the CV values were in acceptable ranges. 4. Workshops titled "National health examination for tumors" and "Standardization and harmonization of laboratory tests" were held on September 4, 2009 and December 16, 2009 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control, and Immunoserology Subcommittee, respectively. The quality of the participating laboratories seems to be continuously improved. And, this year, new sixty eight laboratories were participated to our Immunoassay Subcommittee.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2008) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2008. The first and the second trials assessed by three test categories, i.e., tumor markers, thyroid hormones and immunoproteins (IgG, IgM, IgA, C3 and C4). Fifteen test items using immunoassay method were surveyed as scheduled. The number of participated laboratory of external quality assessment for Immunoassay Subcommittee were 437 institutions in the first trial survey and 476 institutions in the second survey.Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (Liquimmune(R), Liquid Assayed Immunoassay Control, Microgenics Co, USA) were used. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 437 and 476 laboratories and the response rate were 94.6% and 98.7% in 2008. 2. Chemiluminiscence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories for detecting tumor markers and hormones. 3. Some analyzers of a few test items showed variations of the test results of the same control material probably due to personal factors of the institution. 4. Workshops titled "Quality control of Immunoassay" and " Quality control of tumor markers" were held on September 5, 2008 and December 3, 2008 in cooperation with Annual Autumn Academic Conferences of Clinical laboratory and Quality Control and Immunoserology Subcommittee. The quality of the participating laboratories seems to be thought being continuously improved. And, this year, about 51 laboratories are newly participated to our Immunoassay Subcommittee.

The Current Status of HIV Serologic Testing in Korean Clinical Laboratories during the Year 2007 / 대한수혈학회지

BACKGROUND: HIV serologic testing is essential for blood donor screening, and the test results should be accurate. It is important that clinical laboratories perform quality control, quality management and standardization for obtaining accurate laboratory results. The Korean National Institute of Health, the Division of AIDS and the Center for Immunology and Pathology have all performed annual external quality surveillance assessment (EQS, EQA) with using a 5 sera panel for all the Korean HIV testing laboratories that have collaborated with the Quality Assurance Committee of the Korean Society of Laboratory Medicine since 2005. The results of HIV testing in the clinical laboratories during the year 2007 were analyzed. METHODS: The results for the clinical laboratories that participated in the HIV EQAS during 2007 were collected and analyzed. The HIV test results and questionnaire data were sent to the web site "http://hivqa.nih.go.kr". Three hundred thirty two results from 303 institutions in 2007 were analyzed. RESULTS: The most widely used HIV testing method was an automated chemiluminescent immunoassay, such as the Abbott AxSym and the Architect system or the Roche Elecsys. About 5% of erroneous results were reported among 332 results. The causes of error were mostly clerical errors and specimen errors. CONCLUSION: The current status for HIV testing in Korean clinical laboratories was that fully automated immunoassay analyzers were used along with manual POCT tests.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2007) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2007. The first and the second trials assessed by three test categories, tumor markers, thyroid hormones and immunoproteins(IgG, IgM, IgA, C3 and C4). All of fifteen test items using immunoassay method were surveyed. The response rates of external quality assessment for Immunoassay Subcommittee were 98.3%in first trial and 98.8% in second trial in 2007. Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (LyphoCheck, BioRad, USA) were used for external survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 400 laboratories and the response rates were 95.4% and 98.8% in 2007. 2. Recently chemiluminescence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories. 3. Still some test items show big variations of the test results of the same control material according to reagents and autoanalyzers. 4. A workshop for "Quality control practices of Immunoassay" was held on September 7th, 2007 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control. The quality of the participating laboratories seems to be continuously improved. And, this year, many laboratories are newly participated to Immunoassay Subcommittee. A new surveillance system for the individual laboratory according to its performance by method and analyzer is on scheduling for special performance-based QC.

Annual Report on External Quality Assessment of Immunoassay Subcommittee in Korean Clinical Laboratory Survey (2007) / 임상검사와정도관리

Two trials of external quality assessment were performed in 2007. The first and the second trials assessed by three test categories, tumor markers, thyroid hormones and immunoproteins(IgG, IgM, IgA, C3 and C4). All of fifteen test items using immunoassay method were surveyed. The response rates of external quality assessment for Immunoassay Subcommittee were 98.3%in first trial and 98.8% in second trial in 2007. Fourteen control materials consisted of 12 home-made pooled sera and 2 commercial control sera (LyphoCheck, BioRad, USA) were used for external survey. The results are summarized as follows. 1. Laboratories participating in external quality control program of immunoassay were 400 laboratories and the response rates were 95.4% and 98.8% in 2007. 2. Recently chemiluminescence immunoassay autoanalyzers were most commonly used for immunoassay testing in the clinical laboratories. 3. Still some test items show big variations of the test results of the same control material according to reagents and autoanalyzers. 4. A workshop for "Quality control practices of Immunoassay" was held on September 7th, 2007 in cooperation with Annual Autumn Academic Conferences of Clinical Laboratory and Quality Control. The quality of the participating laboratories seems to be continuously improved. And, this year, many laboratories are newly participated to Immunoassay Subcommittee. A new surveillance system for the individual laboratory according to its performance by method and analyzer is on scheduling for special performance-based QC.

Development of ELISA-kit of Quantitative Analysis for Adiponectin and Their Correlation with Cardiovascular Risk Factors / 한국역학회지

PURPOSES: To develop a rapid, sensitive, qualitative ELISA-kit for serum adiponectin and examine correlation with adiponectin and cardiovascular risk factors. METHODS: On the base of monoclonal antibodies against adiponectin, apply indirect ELISA to study the performance parameter of the kit. The correlation was examined between adiponectin and cardiovascular risk factors including waist circumference, body mass index, triglyceride, and HDL cholesterol. RESULTS: The limited concentration of detection of the ELISA-kit was 1ug/ml. Linearity with R&D system and AdipoGen with this ELISA-kit was acceptable: the linear equation with R&D system was y=1.0116x + 0.4629 (R2=0.97) and linear equation with AdipoGen was y=0.9562x + 1.1961 (R2=0.93), respectively. The average recovery rate of the ELISA-kit ranged 92 to 104%. The correlation coefficient of waist circumference with adiponectin was -0.2276 (p<0.0001) among men and -0.2328 (p<0.0001) among women. CONCLUSION: This ELISA-kit was quick, sensitive, and stable and can be used to determine adiponectin in serum.

The Association Between Adiponectin and Diabetes in the Korean Population / 한국역학회지

BACKGROUND: As indicators of obesity, waist circumference (WC), body mass index (BMI), and adiponectin are well known risk factor for diabetes mellitus. The objectives of this study were to measure the independent association between these obesity indicators and diabetes and to examine the combined effect of these indicators on diabetes in a Korean population. METHODS: The WC, BMI, and serum adiponectin were measured in 6,505 healthy Koreans and were classified into tertile groups for men and women. The independent and combined associations of the obesity indicators with diabetes were measured using logistic regression analyses. Diabetes was defined as fasting serum glucose greater than 126 mg/dL or taking medication. RESULTS: Levels of adiponectin were inversely associated with BMI and WC and directly associated with age and high density lipoprotein cholesterol (HDL) cholesterol (P <0.001). After adjusting for age, WC, and other lifestyle factors, low levels of adiponectin were associated with an increased prevalence of diabetes. Further adjustment for HDL cholesterol and triglyceride attenuated this association in both men and women. The best cut-off value of adiponectin in terms of identifying the presence of diabetes was 5.5 /ml with a sensitivity and specificity of 46.7% and 63.9% for men and 9.5 /ml with a sensitivity and specificity of 68.2% and 55.2 for women. CONCLUSIONS: These results suggest that adiponectin was associated with diabetes. The association was independent of WC and was partly modified by HDL and triglyceride. There were no effect modifications of adiponectin with WC on diabetes.

MSX1 Polymorphism Associated with Risk of Oral Cleft in Korea: Evidence from Case-Parent Trio and Case-Control Studies

Orofacial clefts, including cleft lip with or without palate (CL/P) and cleft palate (CP), are one of the most common congenital malformations in Asian populations, where the rate of incidence is higher than in European or other racial groups. A number of candidate genes have been identified for orofacial clefts, although no single candidate has been consistently identified in all studies. We performed case-parent trio and case- control studies on 6 single nucleotide polymorphisms (SNPs) in the MSX1 gene using a sample of 52 CL/P and CP probands from Korea. In the case-control study, the allele frequencies of 6 MSX1 SNPs were compared between 52 oral cleft cases and 96 unmatched controls. For the case-parent trio study, single-marker and haplotype-based tests of transmission disequilibrium using allelic and genotypic tests revealed significant evidence of linkage in the presence of disequilibrium for 1170 G/A of exon 2. With the GG genotype as a reference group among GG, GA, and AA genotypes at 1170G/A, the disease risk decreased with the presence of the A allele (AA genotype: OR=0.26, 95% CI=0.10-0.99). These results are consistent with evidence from other studies in the US and Chile and confirm the importance of the MSX1 genotype in determining the risk of CL/P and CP in Koreans.