Roche RIA and Abbott EIA carcinoembryonic antigen assays compared

We have evaluated Roche Diagnostics' RIA-CEA and Abbott Diagnostics' EIA-CEA methods for precision, normal reference interval, concordance, and correlation of malignant disease with increase in carcinoembryonic antigen (CEA) in plasma. In examining concordance, we used data on 138 patients with primary carcinomas of the breast, colon, lung, or pancreas, each further classified by extent of dissemination. We find the two methods to be comparably precise. The respective upper reference limits of normal for the Roche and Abbott methods were determined to be 5.0 micrograms/L and 4.6 micrograms/L. The regression equation for a log transformation of the 177 data points is y = 0.966x + 0.03, where x = Roche and y = Abbott, with a correlation coefficient of 0.948. According to the criteria we used, the concordance was 78.7%. The largest discordance was observed in widely disseminated disease states and in cancers of the colon and pancreas. Paired data analysis of discordance indicated greater increases in apparent CEA by the Abbott method in most colon cancers with liver involvement; six of the eight discordant pancreatic cancers had higher Roche-CEA values. CEA heterogeneity and the role of the liver in CEA metabolism appear to contribute to the observed differences. We show why the two methods should not be used interchangeably, and that baseline values for CEA must be established for each method.     

Comparison of Abbott AxSYM and Roche Elecsys 2010 for measurement of BNP and NT-proBNP

BACKGROUND: B-type natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are small cardiac hormones released from the heart. They can be used as an important aid to diagnose congestive heart failure (CHF). METHODS: We compared the performances of the Abbott AxSYM and Roche Elecsys 2010 for the measurement of BNP and NT-proBNP. The first method uses a microparticle enzyme-linked immunoassay, whereas the other uses chemiluminescent immunometric assay. RESULTS: The CVs using pooled sera ranged from 3.7% to 12.7% for the AxSYM and 0.9% to 2.2% for the Elecsys 2010. The Passing and Bablok regression was Elecsys 2010 NT-proBNP=7.23xAxSYM BNP+2.53. The BNP in EDTA plasma was more stable than in serum. The immunoreactivity difference of NT-proBNP in serum or EDTA plasma was within 10% when stored at 4 degrees Celsius or 25 degrees Celsius for 72 h. Receiver operating characteristic (ROC) curves were different for both assays, and the areas under the curves were 0.704 and 0.841 for the AxSYM and Elecsys 2010 method, respectively. CONCLUSIONS: Both assays were not entirely specific for heart failure. The precision and stability for NT-proBNP was better than for BNP in serum. It is important to use method-appropriate reference ranges (or cutoff) for the BNP and NT-proBNP, respectively, in the assessment of CHF.     

罗氏e601型电化学发光分析仪测定癌胚抗原的方法学性能评价

目的通过对罗氏e601型电化学发光分析仪测定癌胚抗原的方法学性能评价,探讨临床免疫学定量检测的方法学性能验证评价方案和实验方法。方法按照CLSI推荐的方法测定癌胚抗原的精密度、正确度、线性范围和可报告范围、分析灵敏度（最低检测限）、生物参考区间的验证、携带污染率指标进行验证。结果癌胚抗原的方法学评价结果在厂家提供的范围之内,癌胚抗原的生物参考区间范围不受地区和人群等因素的影响。结论罗氏e601型电化学发光分析仪检测系统性能能满足临床要求,评价方案科学可靠,厂家提供的数据必须经验证后才能引用。     

Comparison of monoclonal and polyclonal enzyme immunoassays for carcinoembryonic antigen

A new commercially available CEA immunoassay, using monoclonal antibody, was evaluated for the purpose of routine clinical use. The between-day coefficient of variation was 5.2% at the 6.6 micrograms/l level and 4.1% at the 14.2 micrograms/l level. The results of analysis of sera from 260 patients were compared with the data from an established method with polyclonal antiserum. A good correlation between the two methods was found. When the patients were classified according to groups with known types of carcinomas no systematic differences between the monoclonal and polyclonal modes of assay were apparent. Relatively large differences in serum CEA levels did occur in individual patients necessitating a transition period in changing from one method to the other.     

Comparison of the Roche COBAS Amplicor Monitor, Roche COBAS Ampliprep/COBAS Taqman and Abbott RealTime Test assays for quantification of hepatitis C virus and HIV RNA.

BACKGROUND: We have evaluated the performance of two newly developed automated real-time PCR assays, the COBAS Ampliprep/COBAS TaqMan (CAP/CTM) and the Abbott RealTime tests, in the quantification of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) RNA. The widely used semi-automated COBAS Amplicor Monitor (CAM) assay served as the reference test. METHODS: Several specimens were analyzed, including 102 plasma samples from HCV patients and 109 from HIV patients and 10 samples from negative donors, as well as Quality Control in Molecular Diagnostics (QCMD) and National Institute for Biological Standards and Controls (NIBSC) proficiency program panels. RESULTS: Good correlation was observed among the three assays, with correlation coefficients (R2) of 0.8 (CAM-CAP/CTM), 0.89 (CAM-RealTime) and 0.91 (CAP/CTM-RealTime) for HCV and 0.83 (CAM-RealTime), 0.85 (CAM-CAP/CTM) and 0.89 (CAP/CTM-RealTime) for HIV. The overall concordance for negative/positive results was 100% for HCV and 98% for HIV. All assays were equally able to quantify HCV genotypes 1, 3, 5 and HIV group M (subtypes A-H) and N from QCMD and NIBSC panels. In terms of workflow, the RealTime assay requires more hands-on-time than the CAP/CTM assay. CONCLUSIONS: The results indicate that real-time PCR assays can improve the efficiency of end-point PCR tests by better covering viral dynamic ranges and providing higher throughput and automation.     

罗氏 Cobas e601与雅培 Architect i2000检测乙肝表面抗原的比较

目的：比较罗氏电化学发光检测仪Cobas e601与雅培化学发光微粒子免疫分析仪Architect i2000检测乙肝表面抗原的结果。方法选取在雅培 i2000检测仪上检测乙肝表面抗原结果为有反应性,且定量结果小于250 IU/mL 的标本,同时在罗氏 e601进行检测,分析比较检测结果间的差别,并进行直线相关和回归分析。结果共检测46份临床标本,剔除1份两台仪器上检测结果反应性不符的标本外,其余结果具有很好的相关性。其中雅培检测值为0．05～1．00 IU/mL 的15份,两者的直线回归方程为Y ＝17．49X ＋0．843,相关系数 r＝0．979;1．1～10．00 IU/mL 的15份,两者的直线回归方程为Y ＝15．72X ＋21．06,相关系数 r＝0．952;11～250 IU/mL 的15份,两者的直线回归方程为Y ＝29．17X -129,相关系数 r＝1．000。结论两种方法的检测结果具有很好的相关性,并可以通过公式进行相互换算。     

Comparison of whole plasma and perchloric acid-extracted plasma assays for carcinoembryonic antigen.

A direct, paired, comparison was made of two plasma radioimmunoassays for carcinoembryonic antigen (CEA), between a perchloric acid-extracted, ammonium sulphate precipitation method; and a whole-plasma, double-antibody method. For both assays the same preparations of standard CEA, 125I-labelled CEA, and anti-CEA serum were used. Plasma samples were taken from young healthy subjects (24), cancer-free hospital inpatients (44) and cancer-proven untreated patients (94). Within-batch and between-batch variation were both greater for the extracted-plasma method. Cancer discriminatory ability was assessed by probabilistic means. With cancer-free inpatients as the reference group, no difference between the assay methods was revealed. With young healthy subjects as the reference group the whole-plasma assay was superior.     

Comparison of different methods for measuring intra-abdominal pressure

OBJECTIVE: Intra-abdominal pressure (IAP) can be measured in different ways but is usually measured indirectly via the urinary bladder. The aim of the study was to: 1) compare urinary bladder pressure, femoral vein pressure, and inferior caval vein pressure with IAP at different levels of IAP; and 2) try to find an optimal amount of fluid to be instilled into the urinary bladder before measurement of the bladder pressure, and to compare changes in blood flow in the femoral vein with that in the caval vein at different pressure levels. DESIGN: Experimental study. SETTING: Animal research laboratory. SUBJECTS: Eight domestic swine of both sexes, weighing 30.6+/-2.9 kg (mean+/-SD). INTERVENTIONS: Catheters connected to pressure transducers were placed into the urinary bladder, the inferior caval vein, the femoral vein, and the superior caval vein. Transit time flow probes were placed around the inferior caval vein and the femoral vein. After a stabilizing period, the abdominal pressure was increased stepwise by instillation of Ringer's solution into the abdomen and then decreased. Thereafter, we instilled fluid into the bladder at an IAP of 8 mmHg and at 20 mmHg and measured the amount of fluid needed to elevate the intra-vesical pressure by 2 mmHg. RESULTS: The pressures recorded in the urinary bladder, the inferior caval vein, and the femoral vein reflected the pressure in the abdominal cavity very well. The fluid volume needed to increase the bladder pressure by 2 mmHg was significantly lower at 20 mmHg IAP than at 8 mmHg. Blood flow in the femoral vein and the inferior caval vein showed a similar pattern and decreased when the intra-abdominal pressure increased. CONCLUSIONS: In our porcine model, and increasing the IAP by means of instillation of Ringer's solution, a reliable estimation of the IAP was obtained by measuring the pressure in the urinary bladder, the femoral vein or the inferior caval vein. The IAP estimated indirectly as the urinary bladder pressure is affected by the amount of fluid in the bladder, which should not exceed 10-15 ml. The decrease in femoral vein blood flow reflects the changes in inferior caval vein flow during increased IAP.     

四种血糖测定方法的比较

目的了解四种血糖测定方法结果的差异及影响因素。方法分别用己糖激酶法（HK）、氧化酶法（GOD—POD）法和手工比色法测定53例患者血清葡萄糖浓度,同时用血糖监测仪测定患者毛细血管血葡萄糖浓度,然后对四组测定结果进行配对资料t检验处理及相关性分析。结果血糖正常时,HK法比GOD—POD法结果平均高0．13mmol／L（2．5％）,比手工比色法结果平均高0．49mmol／L（9．4％）,比血糖监测仪结果平均高0．30mmol／L（5．7％）,分别对HK法与GOD-POD法、GOD-POD法与手工比色法、HK法与血糖监测仪进行相关分析,相关系数1分别为0．99、0．94和0．68;高血糖时,HK法比GOD-POD法结果平均高0．20mmol／L（1．7％）,比手工比色法结果平均高1．84mmol／L（15．7％）,比血糖监测仪结果平均高1．5mmol／L（12．9％）,其相关系数吖分别为0．99、0．95和0．85。结论血糖正常时,HK法与GOD-POD法、手工比色法、血糖监测仪所测结果均有显著性差异,P值分别为〈0．01、〈0．01及〈0．05;高血糖时,HK法与GOD-POD法、手工比色法及血糖监测仪所测结果均有显著性差异,P值均〈0．01。相关性分析表明,HK法与GOD—POD法呈高度直线正相关,GOD-POD法与手工比色法相关性良好,而HK法与血糖监测仪相关性较差。     

Comparison of the Abbott IMx and a high-performance liquid chromatography method for measuring total plasma homocysteine.

The determination of the total concentration of plasma homocysteine is of interest in a variety of clinical circumstances, especially, in the evaluation of the risk of cardiovascular disease. However, most of the methods available to date, many of them chromatographic, are not well suited for the majority of clinical laboratories. Several automated methods are now or will be, shortly, commercially available. We have compared one of them, the fluorescence polarization immunoassay (FPIA) adapted to the IMx analyzer (Abbott Laboratories), with the high-performance liquid chromatography (HPLC) method with fluorescent detection currently used in our laboratory. The results show that the FPIA-IMx method is less imprecise and slightly more sensitive than the HPLC. The comparison of 67 clinical plasma specimens indicated that there is a proportional error disagreement between FPIA-IMx and HPLC (FPIA=1.19 HPLC + 0.92; confidence region for slope and y-intercept were, respectively, from 1.06 to 1.31 and from -0.06 to 2.32). The nature of this error is not explained by the experiments performed to study the inaccuracy of both methods, which included the investigation of dilution parallelism, analytical recovery and cross-reactivity. The different results of homocysteine concentration obtained with FPIA-IMx and HPLC must be taken into account when a change of methodology is under consideration.     

两种定量检测甲胎蛋白与癌胚抗原的方法比较

目的 对两种不同方法检测甲胎蛋白(AFP)与癌胚抗原(CEA)的重复性及检测结果的差异进行方法学对比和偏倚评估,探讨不同分析方法检测结果是否具有可比性及偏倚是否在允许范围内.方法 以可溯源的罗氏电化学发光法检测结果为比较方法,以时间分辨法检测结果为实验方法.结果 经F检验,两种仪器检测甲胎蛋白与癌胚抗原的差异无统计学意...     

三种方法测定血浆纤维蛋白原的结果比对

目的对克劳斯（vonClauss）法、免疫透射比浊法、凝血酶原时间（PT）演算法（PT—Der法）测定纤维蛋白原的结果进行评价并探讨其影响因素。方法用以上三种方法分别测定40例一般患者（Ⅰ组）、20例心脑血管病患者（Ⅱ组）、20例纤维蛋白原含量减少患者（Ⅲ组）的纤维蛋白原（Fib）,并对高、中、低值Fib分别作批内、批间精密度及黄疸、溶血、脂血分析,结果用SPSS10．0软件进行统计学处理。结果在重复性实验中,vonClauss法精密度最高,免疫透射比浊法精密度良好。PT—Der法精密度高值较差,中、低值良好。Ⅰ组Fib差异无统计学意义;Ⅱ组差异有统计学意义;Ⅲ组PT—Der法Fib值差异有统计学意义,免疫透射比浊法结果差异无统计学意义。严重脂血PT-Der法有显著性差异。结论vonClauss法测定Fib精密度高,与免疫透射比浊法均不受黄疸、脂血、溶血标本的影响。PT—Der法、免疫透射比浊法对高、低值Fib测定有不同程度的差异,可用于手术前常规检查或健康人体检筛查。对高、低值标本最好采用vonClauss法。     

Comparison of three methods for measuring central venous pressure

We used a digital display value, a recorded pressure curve, and manometric measurements to determine CVP in 35 ICU patients who had either a central venous line or a pulmonary artery catheter. CVP was measured by each method up to five times per patient, for a total of 107 data sets. Display values compared well to those from the recorded pressure curve. Manometric measurements, however, poorly matched electronically determined values. Factors influencing these results are discussed.     

3种C反应蛋白检测方法的比较

目的：比较3种检测 C 反应蛋白方法的检测结果。方法收集该院100例就诊患者,分别采用3种不同的 C 反应蛋白检测方法分析血液中 C 反应蛋白浓度。结果相关性分析表明,免疫比浊法和免疫层析法检测结果的相关性较高（r ＝0．9920）。方差分析发现,采用免疫比浊法检测的 C 反应蛋白浓度正常者中,个体间 C 反应蛋白浓度间差异有统计学意义（P ＜0．05）,而 C 反应蛋白异常者中,个体间差异不显著（P ＞0．05）,所有受试对象个体间 C 反应蛋白浓度差异也具有统计学意义（P ＜0．05）。结论C 反应蛋白检测对于诊断炎症有重要意义。     

Comparison of three noninvasive methods for measuring scoliosis.

The premise behind most noninvasive techniques for the measurement of scoliotic conditions of the spine is that the lateral distortion of the spine relates directly to transverse rib cage deformity within the transverse plane. The focus of this study was to examine this assumption by comparing different noninvasive methods for the assessment of scoliotic curves. The three techniques examined were (1) use of the Scoliometer (SCOL), (2) use of the back-contour device (BCD), and (3) use of moiré topographic imaging (MTI). Fourteen subjects (10 female, 4 male) with idiopathic adolescent scoliosis were measured. Posterior-anterior radiographs were obtained for the clinical assessment of all subjects and were subsequently used to determine Cobb angles. Significant correlations between axial trunk rotation and Cobb-angle measurements were observed in the thoracic region (MTI, r = .80, df = 10, P less than .005; BCD, r = .70, df = 10, P less than .025; SCOL, r = .59, df = 10, P less than .025) but were not found within the lumbar region (MTI, r = .42; BCD, r = .17; SCOL, r = .20). Factors other than trunk deformity, such as the posture assumed by the subject during measurement, may have influenced axial trunk rotation. Hence, the techniques appear to provide valid estimations of lateral curvature of the spine in the thoracic region of the trunk but not the lumbar region. The results suggest that the measurement techniques cannot be used interchangeably in clinical recording.