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.

Performance Characteristics of the UniCel DxI 800 Immunoassay for the Maternal Serum Quadruple Test, Including Median Values for Each Week of Gestation, in Korean Women / 대한진단검사의학회지

BACKGROUND: Maternal serum prenatal quadruple screening includes testing for alpha-fetoprotein (AFP), human chorionic gonadotrophin (hCG), unconjugated estriol (uE3), and dimeric inhibin A (DIA). We evaluated quadruple screening using an automated platform and looked for any ethnic differences in the median values of each marker. METHODS: We measured the concentrations of each quadruple test analyte using the UniCel DxI 800 system (Beckman Coulter, USA) in 788 Korean mid-trimester maternal serum samples and calculated their median values using Benetech software (Benetech, Canada). We also compared the results with those obtained using the Immulite 2000 assay (Siemens Healthcare Diagnostics, USA) or ELISA (DSL, USA) in 442 samples. RESULTS: We obtained mid-trimester median values for each marker. The following are the comparative results for each test using the Immulite 2000 assay or ELISA (x) and the UniCel DxI 800 immunoassay (y): AFP, y=1.10x+0.01, r=0.925; uE3, y=0.28x+0.24, r=0.885; hCG, y=1.22x-3047.8, r=0.944; and DIA, y=0.86x+15.31, r=0.833. Assay results for each of the four markers showed good correlations. However, significant biases necessitated new median calculations of prenatal risk estimates in all four tests. CONCLUSIONS: We established gestational age-specific second-trimester median values for four markers in Korean samples using the UniCel DxI 800 immunoassay system. Despite significant bias, there were good correlations between the results obtained using the UniCel DxI 800 immunoassay and those obtained using the Immulite 2000 assay.

Variabilidade interensaios de dislipidemias em pacientes hipertensos / Inter-assays variability of dislipidemias in hypertensive patients

INTRODUÇÃO E OBJETIVOS: Ensaios de diferentes procedências para avaliação das dislipidemia podem resultar em variações significativas nos resultados obtidos e consequente conduta inadequada pelo clínico. O estudo objetivou comparar resultados laboratoriais de colesterol total (CT), triglicérides (TG), colesterol da lipoproteína de alta densidade (HDL-C), colesterol da lipoproteína de baixa densidade (LDL-C), apolipoproteína A-1 (Apo A-1), apolipoproteína B (Apo B) e lipoproteína (a) (Lp[a]) e índices lipídicos (não-HDL-C, CT/HDL-C, LDL-C/HDL-C, TG/HDL-C e Apo B/HDL-C) de pacientes hipertensos e/ou diabéticos diagnosticados. MÉTODOS: Foram utilizados conjuntos reativos, e os respectivos analisadores Gold Analisa, Dia Sys (CCX - Abbott), Dade Behring (Nefelômetro BN 100) e Roche (COBAS Integra 400), para verificar a reprodutibilidade dos resultados obtidos. Participaram 99 pacientes (36 do sexo masculino e 63 do feminino). Comparando os resultados, verificamos que: todas as médias obtidas dos constituintes lipídicos apresentaram diferença significativa; número semelhante de pacientes apresentou níveis séricos elevados de CT, TG, Lp(a) e Apo A-1. O HDL-C, o LDL-C e a Apo B apresentaram discordância, assim como os índices de CT/LDL-C, LDL-C/HDL-C e TG/HDL-C. Para não-HDL-C e ApoB/HDL, houve semelhança no número de pacientes com valores não recomendados. Em consequência da diferença, em relação ao LDL-C, a decisão da conduta terapêutica poderá ser inadequada, enquanto o não-HDL-C, além de evidenciar partículas aterogênicas, apresentou número de hipertensos com valores séricos não referendados semelhantes, independente da metodologia e do equipamento utilizado. CONCLUSÃO: No grupo de hipertensos analisados, o não-HDL-C se caracterizou um importante fator de correção interensaios de parâmetros lipídicos. E sua associação à relação Apo B/HDL-C pode ser um fator adicional em relação às condutas hipolipemiantes a serem adotadas.

INTRODUCTION AND OBJECTIVES: Different assays to evaluate dyslipidemia may show significant variations in the obtained results and a consequent inappropriate clinical approach may be adopted. This study aimed to compare the results of total cholesterol (CT), triglycerides (TG), HDL-C, Apo A1, Apo B, lipoprotein (a) and lipidic indexes (not-HDL-C, CT/HDL-C, LDL-C/HDL-C, TG/HDL-C and Apo B/HDL-C) of hypertensive and/or diabetic patients. METHODS: The following reactive kits and respective analyzers were applied to verify the reproducibility of results: Gold Analisa, DiaSys (CCX-ABBOTT), Dade Behring (Nephelometer BN 100) and Roche (COBAS Integra 400). Ninety nine patients (36 male and 63 female gender) were investigated. Comparing the results, we observed that all mean numbers of lipid constituents showed a significant difference. A similar number of patients had high CT, TG, Lp (a) and Apo A-1 serum levels. There was also disagreement in HDL-C, LDL-C, ApoB, CT/LDL-C, LDL-C/HDL-C and TG/HDL-C indexes. For not-HDL-C and ApoB/HDL, there was similarity in the number of patients with not recommended values. As a consequence of this difference, the choice of therapeutic approach may be inappropriate as to LDL-C levels, whereas Not-HDL-C not only showed atherogenic particles but also a number of hypertensive patients with similar not recommended serum values, regardless of the methodology and the equipment used. CONCLUSION: In the analyzed group of hypertensive patients, not-HDL-C was an important inter assay correction factor of lipidic parameters. The association with Apo B/HDL-C relation may be an additional factor as to the choice of hypolipemiant treatments.

Current Status of Serum Allergen Tests in Korea / 대한진단검사의학회지

BACKGROUND: Due to the westernization of living environments in Korea, a number of allergy patients are greatly increasing. External quality control assessments are difficult for allergy tests due to the lack of reference methods. We surveyed the current status of allergy tests performed in medical laboratories in Korea to prepare for an external quality control assessment in the near future. METHODS: We conducted a survey on internal and external quality control trials, calibrations and its intervals, medical staffs, analyzers in use, an average number of tests per months, and report formats. RESULTS: Among the 85 laboratories surveyed, 61 were doing allergy tests including 6 reference laboratories. There were two different types of analyzers (1) qualitative or semi-quantitative and (2) quantitative. These analyzers use either chemiluminescent or immunoblot method. Fifty-five laboratories were using 'qualitative or semi-quantitative' analyzers as a screening test and 31 laboratories were using quantitative analyzers. Most of the laboratories were only doing an internal quality control assessment included in the test kits. Excepting a few laboratories, calibrations were not done. About 34 laboratories reported numerical values with interpretative reports prepared by laboratory medical doctors. CONCLUSIONS: The necessity of external quality control assessment has become an issue for improving the quality of allergy tests. But due to the lack of standardization, it is difficult to carry out external quality control assessments. By grouping the laboratories in terms of the type of analyzers, we could overcome the problem of analyzer variations and launch an external quality control assessment program in the near future.

Evaluation of rapid kits for detection of HIV, HBsAg and HCV infections.

Diagnostic kits (J. Mitra Co. Ltd) for rapid detection of HIV, HBsAg & HCV were evaluated against respective enzyme immunoassay (Ortho Diagnostics). All rapid kits were 100% specific for HIV, HBsAg & HCV. Sensitivity for HIV, HCV & HBsAg was 80%, 87.5% & 93.4% respectively.