Centaur Immunoassay Research Articles

Relation of Vitamin D Deficiency with Breast Cancer Staging in Patients from INMOL Cancer Hospital

Introduction: Vitamin D deficiency can be critical and is reported to be as one of the factors for development and progression of breast carcinoma.
 Aims & Objectives: To measure and compare 25(OH)D (calcidiol) levels in healthy females and in breast carcinoma patients in four different stages. Place and 
 duration of study: This cross sectional study and research was conducted in Shaikh Zayed Medical Complex in the Department of Biochemistry and Chemical Pathology from Jan 2018 to Jan 2019. The patients were selected from INMOL Cancer Hospital, Lahore.
 Material & Methods: The study was carried out on 39 healthy females (controls) and 156 newly diagnosed cases of carcinoma breast from stage I to IV, 39 patients of each stage. 25(OH)D was determined in blood samples of patients by ADVIA Centaur (XP) immunoassay system.
 Results: In this study the mean 25(OH)D level of healthy females with mean age of 41.7 ± 15.8 years, was 25.1 ± 5.5ng/ml. 25(OH) D level of breast cancer patients was found to be decreasing with stage progression. For the stage I the average 25(OH)D level was 12.31ng/ml, stage II was 9 ng/ml, stage III was 8.3 ng/ml and stage IV was 8.4 ng/ml.
 Conclusion: It was found that healthy group of females had higher values of serum vitamin D levels as compared to breast carcinoma patients. Low concentration of serum vitamin D may contribute to the progression of stage of breast carcinoma.

Accuracy of Two Progesterone Immunoassays for Monitoring In Vitro Fertilization.

Progesterone concentrations are routinely monitored during in vitro fertilization cycles. Immunoassay-based platforms are used most often in this setting because they are simple to use and amenable to same-day sample collection and result-reporting. However, immunoassay methods are subject to variation in specificity between different assay manufacturers. In this study, a set of unexpectedly high progesterone concentrations led to a method comparison between two in-house immunoassay platforms relative to the reference method. Progesterone was measured in 28 serum samples from women undergoing IVF cycles using the Siemens ADVIA Centaur Immunoassay system and the Abbott Architect i1000SR analyzer. A subset of these samples was selected for progesterone measurement by liquid chromatography-tandem mass spectrometry to define the accuracy of each immunoassay. The Siemens ADVIA Centaur immunoassay system overestimated progesterone concentrations by 19% and the Abbott Architect overestimated progesterone concentrations by 5%. The Abbott Architect progesterone immunoassay provides a more accurate measurement of serum progesterone than the Centaur immunoassay at concentrations relevant for monitoring in vitro fertilization populations.

36 Institutional Adherence to CDC Guidelines for Hepatitis C Virus Screening Reveals Added Utility of Confirmatory Molecular Testing

Current Centers for Disease Control and Prevention (CDC) recommendations for hepatitis C virus (HCV) screening include confirmation of reactive HCV antibody (HCVAB) results for all patients and confirmation of nonreactive results for patients who may have been exposed within the past six months. Our aim was to assess adherence to these recommendations at a 1,250-bed tertiary care hospital in the Midwestern United States. In cases for which confirmatory testing was performed, our secondary aim was to determine the accuracy of the HCVAB screen for the assessment of active HCV infection. We retrospectively identified consecutive HCVAB samples tested by the ADVIA Centaur Immunoassay System over a period of seven years (January 2010 to December 2016) and by the COBAS AmpliPrep/COBAS TaqMan HCV RNA viral load assay (HCVRNA) over the same time period. The HCVAB test results were recorded as well as the percentage of reactive and nonreactive results that received confirmatory testing within 30 days. When both tests were performed, we calculated the concordance rates. Using the HCVRNA as the gold standard, we calculated the positive predictive values (PPVs) and negative predictive values (NPVs) of the HCVAB for the detection of active HCV disease within the patient population receiving both tests within 30 days of each other and within the patient population receiving both tests within one day of each other. Over the seven-year period, 66,066 samples were tested for HCVAB; 61,976 (93.8%) were negative, and 4,090 (6.2%) were positive. Of the 4090 HCVAB samples with positive results, 3,607 HCVAB samples underwent HCVRNA testing within 30 days, suggesting 88.2% adherence to CDC guidance for confirmation of positive HCVAB results. Of the 61,976 negative HCVAB results, 1,888 (3.0%) received confirmatory HCVRNA testing within 30 days. Among the 5,495 HCVAB samples followed up by HCVRNA testing within 30 days, there were 892 false-positive (HCVAB-positive, HCVRNA-negative) and 171 false-negative (HCVAB-negative, HCVRNA-positive) results, leading to a HCVAB PPV/NPV of 75.3%/90.6%. When the analysis was limited to HCVAB/HCVRNA test pairs that were taken within 1 day of each other (n = 1,790), the PPV/NPV improved to 78.6%/96.0%. The adherence to CDC confirmatory recommendations for patients with positive HCVAB results is high (88.2%), and a large proportion of patients with negative HCVAB results do not receive additional testing (97.0%). A small but significant proportion of patients with negative HCVAB tests will have a positive viral load within 30 days and even within one day. Although repeat testing in our study was likely to occur primarily among high-risk patients, creating the potential for bias, these findings suggest that patients with ongoing risk factors for HCV should receive follow-up testing with HCVRNA quantification.

MP28-05 A COMBINATION OF NEW PROTEIN BIOMARKERS REDUCES UNNEEDED PROSTATE BIOPSIES AND IMPROVES THE DETECTION OF PROSTATE CANCER: FINDINGS OF A RECENT STUDY

You have accessJournal of UrologyProstate Cancer: Markers I1 Apr 2017MP28-05 A COMBINATION OF NEW PROTEIN BIOMARKERS REDUCES UNNEEDED PROSTATE BIOPSIES AND IMPROVES THE DETECTION OF PROSTATE CANCER: FINDINGS OF A RECENT STUDY Pierre Tennstedt, Thomas Steuber, Annalisa Macagno, Bruno Golding, Ralph Schiess, and Silke Gillessen Pierre TennstedtPierre Tennstedt More articles by this author , Thomas SteuberThomas Steuber More articles by this author , Annalisa MacagnoAnnalisa Macagno More articles by this author , Bruno GoldingBruno Golding More articles by this author , Ralph SchiessRalph Schiess More articles by this author , and Silke GillessenSilke Gillessen More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.818AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Increased prostate volume due to benign disease leads to many false-positive PSA results and consequently to negative prostate biopsies. Previous research indicated that cancer-related protein biomarkers discovered by a genetic-guided approach using a Pten knock-out mouse model could improve prostate cancer diagnosis. The objective of this study was to evaluate if the protein biomarkers are capable of distinguishing benign disease from prostate cancer in men with enlarged prostates. METHODS We conducted a retrospective study of men with a total PSA of 2.0-10 ng/ml, negative DRE and enlarged prostate volume (=35 ml). Serum samples were collected from men before undergoing prostate biopsy at the Martini-Klinik Hamburg, Germany. All samples were taken between 2011 and 2016 following written patient consent. Serum concentration of CTSD, ICAM1, THBS1, OLFM4, TIMP1, and HYOU1 was measured using immunoassays. In addition, total and free PSA were analyzed to calculate %fPSA using the ADVIA Centaur immunoassay system. RESULTS Of the 474 men included in this study, 236 men had a negative biopsy and 238 were diagnosed with prostate cancer. %fPSA discriminated among biopsy-positive and negative patients with an AUC = 0.650 (P <0.001; 95% CI = 0.600-0.699). Logistic regression analysis revealed that the combination of the two proteins CTSD and THBS1 yielded an AUC = 0.834 (P <0.001; 95% CI = 0.797-0.871); and when combined with %fPSA, it resulted in an even higher AUC = 0.845 (P <0.001; 95% CI = 0.810-0.880). At 90% sensitivity for prostate cancer, the specificity of the combination including CTSD, THBS1 and %fPSA was 60% indicating that 141 of 236 negative biopsies could have been avoided (see Figure 1). Independent training on samples collected before March 2013 and testing on the samples thereafter also resulted in a high AUC =0.872 (P <0.001; 95% CI = 0.826-0.918) showing reproducibility of the method. CONCLUSIONS In patients with elevated PSA, negative DRE and enlarged prostate, the method presented is significantly more accurate than %fPSA alone in determining the absence of prostate cancer. The implementation of the method in clinical practice has the potential to significantly lower the rate of prostate biopsies which are negative for cancer by more than 50%. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e339 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Pierre Tennstedt More articles by this author Thomas Steuber More articles by this author Annalisa Macagno More articles by this author Bruno Golding More articles by this author Ralph Schiess More articles by this author Silke Gillessen More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Short-term prognostic value of serum cardiac troponin I levels in neonates with perinatal asphyxia

Background Neonatal hypoxic–ischemic encephalopathy (HIE) is a neonatal brain injury caused by perinatal asphyxia and is a major cause of neonatal morbidity and mortality. Cardiac dysfunction forms a part of the clinical spectrum of multiorgan dysfunction in asphyxiated newborns. The more cardiac dysfunction the patients have, the more severe encephalopathy they would suffer. Cardiac troponin I (cTnI) is one of neonatal HIE-related biomarkers that can aid the diagnosis of perinatal asphyxia and anticipate the severity of associated myocardial dysfunction. Aim The current study was designed to assess the serum cTnI concentration and to evaluate its short-term prognostic value in newborns with HIE. Patients and methods The present study is a prospective observational study conducted on 100 full-term newborn infants in the period from May 2016 to May 2017. Enrolled newborns were divided into two groups: the case group (50 full-term newborn infants with evidence of perinatal asphyxia) and the control group (50 full-term newborn infants without evidence of perinatal asphyxia). Quantitative estimation of serum cTnI concentrations was done in all enrolled newborns within 12 h of birth using direct chemiluminometric technology performed on ADVIA Centaur Immunoassay System (TnI-Ultra). Serum levels of creatine kinase-MB (CK-MB) were also measured to assess its sensitivity and specificity as a marker of perinatal asphyxia. Additionally, echocardiography was done to exclude structural heart diseases. Left ventricular fractional shortening (LVFS) was also measured to assess cardiac involvement. Results Serum concentrations of cTnI were statistically significantly higher among the case group when compared with the control group. Additionally, serum levels of cTnI were found to increase with increasing severity of HIE. Serum levels of CK-MB were also statistically higher among the case group. However, pairwise statistical comparison of serum CK-MB concentrations in different stages of HIE revealed no statistical significant difference. No statistical significant difference was found between the two studied groups regarding LVFS. Moreover, LVFS did not differ significantly between the different stages of HIE. Among the different markers of myocardial dysfunction assessed in the current study, cTnI was found to be the most sensitive and specific predictor of poor short-term outcome in newborns with perinatal asphyxia. When comparing serum concentrations of cTnI and CK-MB in both surviving and nonsurviving newborns in the asphyxia group, it was found that serum concentrations of cTnI were statistically significantly lower in the group of survivors. In contrast, there was no statistical significant difference regarding serum concentrations of CK-MB between surviving and nonsurviving asphyxiated newborns. Conclusion Serum concentrations of cTnI were elevated in asphyxiated newborns with respect to healthy infants and increase with increasing severity of HIE. cTnI can also be used as an excellent early predictor of mortality in newborns with perinatal asphyxia.

SAT0374 Elevated Serum Homocysteine Levels in Gouty Patients were Related Not with Serum Uric Acid Levels but with Decreased Renal Function

BackgroundHyperhomocysteinemia, which is related with cardiovascular diseases and metabolic syndrome, is regarded as one of the important factors in endothelial cell damage processes. It is well known that gout is...

Thyroid-stimulating hormone and free thyroxine on the ADVIA Centaur immunoassay system: A multicenter assessment of analytical performance

ObjectivesWe assessed the analytical performance of the TSH and FT4 assays on ADVIA Centaur in a multicenter national evaluation. Design and methodsA precision study and a method comparison were performed. Reference values stated by the manufacturer were checked from 379 normal subjects. ResultsFor TSH and FT4, the intra-assay CVs were below 2.3 and 5.2%, respectively, and the inter-assay CVs below 4.4% and 7.2%, respectively. Therefore, the precision and reproducibility were acceptable. Bland–Altman bias plots revealed good correlation and agreement with Cobas assays. TSH and FT4 data yielded reference ranges of 0.64–3.24mIU/L and 10.5–18.9pmol/L, respectively. ConclusionThese assays demonstrate reliable characteristics. The reference ranges obtained can be used for interpretation of thyroid function.

Papel do HER2/NEU sérico como factor preditivo e de monitorização no cancro da mama sob terapêutica com trastuzumab.

In breast cancer, the Human Epidermal growth factor Receptor 2 (HER2) is associated with worst prognosis in all stages of the disease, and it is specifically targeted by a monoclonal antibody (trastuzumab). Nevertheless, the different response rates observed have increased the search for better predictive markers. Elevated levels of the extracellular domain of HER2/neu in the serum have been associated with the clinical outcome of breast cancer patients. The authors proposed to analyze serum HER2/neu in breast cancer patients, under treatment with trastuzumab, in monotherapy or associated with another systemic therapy, either in adjuvant or metastatic setting, in order to evaluate its role as prognostic, predictive and monitoring factor. From March 2007 to May 2008, 173 serum samples from 43 patients were analysed, corresponding to the beginning of the treatment of trastuzumab and 3/3 months afterwards. Serum HER2/neu levels were measured with ADVIA Centaur(®) immunoassay and levels > 15 ng/mL were defined as elevated, according to previous reports. Elevated baseline serum levels were found to be associated with a worst overall survival (p = 0,003). In the metastatic setting, baseline HER2/neu serum levels were not associated with response rate to trastuzumab. However, when we analyzed the variations in HER2/neu serum levels between the response evaluation date and the first measurement, we observed that patients whose serum levels declined showed significantly higher objective response compared with patients with stable or elevated serum values (p = 0,001). Moreover, monitoring early changes in serum levels (three months) could also predict the probability of response to trastuzumab-based treatment (p = 0,007). The use of this predictive potential could not only focus and tailor treatment individually but also adapt to economic needs.

Abstract P3-12-05: Genetic Variation in Prolactin and Prolactin Receptor, and Relationships with Serum Prolactin Levels and Breast Cancer Risk

Abstract Background: Studies support the hypothesis that high circulating levels of the hormone prolactin increase breast cancer risk. It remains unclear if genetic factors are associated with interindividual variation in circulating prolactin and subsequent breast cancer risk. We examined the relationship between single nucleotide polymorphisms (SNPs) in prolactin (PRL) and prolactin receptor (PRLR), serum prolactin levels and breast cancer risk in a population based case-control study. Methods: We genotyped 8 PRL and 20 PRLR tag SNPs in 1943 cases and 2229 controls (82% and 89% of enrolled, respectively). Cases were women 20-74 years old, diagnosed with in situ or invasive breast cancer between 2000 and 2003, and living in Warsaw or Lodz, Poland. Controls were cancer-free women selected from a population registry, matched to cases on age and city. Blood samples were provided at the study interview. Serum prolactin levels were measured in a subset of 773 controls using the Bayer Advia Centaur immunoassay. Odds ratios and 95% CIs for genotype-breast cancer associations were estimated using unconditional logistic regression, adjusting for age and city. Geometric mean prolactin levels and 95% confidence intervals (CI) were estimated using linear regression, adjusting for age, city, blood collection time, and day of menstrual cycle (premenopausal). Log-additive model Wald P-values were used to test for linear trends. Analyses were stratified by menopausal status, and all statistical tests were 2-sided (alpha=0.05). To account for multiple comparisons, P-values were adjusted using the Benjamini and Hochberg method. Results: Three PRLR SNPs were nominally associated with breast cancer: in premenopausal women, rs249537 (per-allele OR 1.39, 95% CI 1.07 - 1.82, P=0.0140); and in postmenopausal women, rs7718468 (per-allele OR 1.16, 95% CI 1.03 — 1.30, P=0.0137) and rs13436213 (per-allele OR 1.13 95% CI 1.01 — 1.26, P=0.0397). We examined serum prolactin levels by genotype for these three SNPs to determine whether the potential risk alleles were associated with increased circulating prolactin, but mean serum prolactin levels were similar by genotype in controls: rs249537 TT=3.83 ng/ml, CT=5.51 ng/ml, CC=5.50 ng/ml, P-trend=0.8381; rs7718468 CC=6.41 ng/ml, CT=6.86 ng/ml, TT=6.47 ng/ml, P-trend=0.5643; and rs13436213 AA=6.48 ng/ml, AG=6.52 ng/ml, GG=6.29 ng/ml, P-trend=0.4766. None of the nominal associations between PRLR genotypes and breast cancer risk were significant after adjusting for multiple comparisons (multiple comparison adjusted P-values: rs249537 P=0.4340; rs7718468 P=0.4340; rs13436213 P=0.8205). PRL SNPs were not associated with breast cancer risk in premenopausal or postmenopausal women. Discussion: Our data do not support an association between PRL or PRLR tag SNPs and breast cancer. Though some associations were nominally significant, these results may be due to random error and require further study. Furthermore, data do not support a relationship between riskassociated SNPs and differences in prolactin levels. Future research should focus on non-genetic factors that affect circulating prolactin levels. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-12-05.

Systemic chemokine levels in breast cancer patients and their relationship with circulating menstrual hormones

The chemokines Stromal Cell-Derived Factor-1alpha (SDF-1alpha/CXCL12) and Monocyte Chemotactic Protein-1 (MCP-1/CCL2) have been implicated in breast cancer progression. We recently reported elevated systemic MCP-1 in breast cancer patients. This study investigated circulating levels of SDF-1alpha in breast cancer patients, and addressed potential hormonal regulation of these two potent chemokines. SDF-1alpha levels were determined by ELISA in 114 breast cancer patients and 85 controls, and correlated with clinical data. Blood samples were collected from 36 healthy premenopausal volunteers weekly for four weeks to measure Luteinising Hormone (LH), Follicular Stimulating Hormone (FSH), Oestradiol and Progesterone using a Bayer ADVIA Centaur Immunoassay system, in parallel with SDF-1alpha and MCP-1. CXCL12 expression was determined using RQ-PCR in primary tumour stromal cells (n = 16) harvested at surgery. Plasma SDF-1alpha was significantly higher in breast cancer patients than age-matched controls and had a significant correlation with tumour grade and epithelial subtype. Investigation of menstrual variations of these chemokines revealed lower SDF-1alpha levels in the mid-luteal phase of the menstrual cycle and a significant positive correlation with circulating Oestradiol. MCP-1 levels showed no correlation with menstrual hormones. There was a trend towards increased CXCL12 expression in tumour compared to normal stromal cells. The elevated level of SDF-1alpha detected in breast cancer patients, and it's correlation with prognostic indicators, highlights the importance of this chemokine in disease progression. Elucidation of factors influencing chemokine secretion supports clarification of their role in tumourigenesis.

Detection of HBsAg mutants in a population with a low prevalence of hepatitis B virus infection

Two independent studies were conducted to evaluate performance of two HBsAg immunoassay products performed on the Abbott ARCHITECT and Bayer ADVIA Centaur immunoassay analyzers. One was a retrospective study of 484 stored samples and the second was a prospective study of 349 samples from random population. In the process of the evaluation, a number of discordant samples from HBsAg-positive patients were found which led to the discovery of a number of HBsAg mutants in the general Australian population. Following viral DNA sequencing, these were identified as HBsAg escape mutants. Whilst the existence of HBsAg mutants has been well documented in various regions of the world, this is surprising in an area of low endemicity and demonstrates the necessity of an HBsAg assay to detect mutants reliably in a diagnostic situation where HBsAg is used as the only marker to detect an HBV infection. These studies demonstrate the ability of the Abbott ARCHITECT and AxSYM HBsAg immunoassays to detect these HBsAg mutations which were not detected by the Bayer ADVIA Centaur.

Evaluation of Plasma Homocysteine Assay by ADVIA Centaur Analyzer

Hyperhomocysteinemia is a risk factor for the cardiovascular diseases that can be usually reversed with vitamin supplements. Quantitative analysis of homocysteine helps to identify patients who might get benefits from the intervention therapy. Recently, as the automated homocysteine assay (ADVIA Centaur, Bayer, USA) by direct chemiluminesence method has been developed, we evaluated the performance of the ADVIA Centaur immunoassay analyzer for homocysteine. The total plasma homocysteine concentrations were measured by ADVIA Centaur and by HPLC (HP1100 series with FLD, Hewlett Packard Co., Germany). To test the linearity, a dilution series was prepared. Between-run and total precision of the ADVIA Centaur assay were evaluated with Bio-Rad Homocysteine Controls for 10 days. The correlation was evaluated using 100 plasma samples from patients. NCCLS guidelines (EP5-A, EP6-P, and EP9-T) were followed to evaluate the ADVIA Centaur homocysteine assay. In the precision study, within-run and total run coefficients of variation (CV) of ADVIA Centaur assay were below 5%. The linearity was maintained well (R(2)=0.9978). The comparison study indicated a good correlation between the HPLC and ADVIA Centaur assay, and its correlation coefficient (R) was 0.9690. Since the ADVIA Centaur homocysteine immunoassay showed an excellent correlation with the HPLC method and is more convenient, automatic, and rapid than the HPLC method, it should be potentially beneficial in the clinical laboratories.

Young adult reference ranges for thyroid function tests on the Centaur immunoassay analyser

This study aims to establish reference ranges for thyroid tests in young Saudi adults using the Centaur immunoassay method. Physical examination is performed and thyroid function tests include thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3). These are performed on 291 young Saudi adults (182 [63%] females and 109 [37%] males; average age: 27 years [range 18–50]). Clinical thyroid abnormality, related symptoms and/or abnormal thyroid function tests exclude a person from the study and thus a total of 276 subjects (171 [62%] females and 105 [38%] males) are used to establish the new reference ranges. Combined female and male ranges for TSH, FT4, and FT3 were found to be 0.48–6.30 miu/L (9.00–18.62 pmol/L and 3.39–6.85 pmol/L, respectively). Mean TSH and FT4 levels were significantly different (P<0.0001) from those quoted by the manufacturer. Ranges for TSH were 0.48–6.30 miu/L (female) and 0.52–4.89 miu/L (male) (P=0.08). Female ranges for FT4 and FT3 were 9.00–17.15 pmol/L and 3.39–5.82 pmol/L, respectively. Male ranges were 9.92–18.62 pmol/L (P=0.0001) and 4.36–6.85 pmol/L (P<0.0001). The range of TSH levels in the young local Saudi population proved to be higher than that quoted by the manufacturer. FT4 range was lower and narrower than that quoted by the manufacturer. Significant differences between female and male populations suggest that partitioning of the reference ranges by gender is necessary.

Serum Concentrations of Vitamin B-12 and Alkaline Phosphatase in Newly Diagnosed Multiple Myeloma Patients.

Background: A controversy about a possible link between vitamin B12 deficiency and multiple myeloma (MM) has persisted since the 1970s. Vitamin B12 (B12) deficiency can cause anemia, neuropathy and has been associated with osteoporosis and reduced bone density. Therefore, B12 deficiency might worsen some clinical symptoms of MM.Methods: We evaluated serum B12 concentrations in 393 untreated MM patients included in the Myeloma Institute Program (October 1998 to March 2005). Total serum B12 was assessed by using ADVIA Centaur immunoassay with chemiluminescent detection; laboratory B12 deficiency was defined as serum B12 levels < 156 mmol/L. Serum alkaline phosphatase (ALP) was determined by a kinetic rate method. Neuropathy was assessed clinically according to NIH guidelines. Correlations of serum B12 concentrations with bone density (radial T- and Z -score) and thalidomide-related neuropathy were investigated. Categorical variables were compared using chi-square and Fisher's exact test, while correlation coefficient was used for quantitative variables.Results: The sample was 57% male, median age = 58 years, stage III 70%, median creatinine 1.0 mg/dL, IgG 52%, IgA 24%, and light chain disease 19%. Prevalence of laboratory B12 deficiency was 3.5%, prevalence of functional deficiency (B12 < 241 mmol/L) was 20.4%. No influence of age or MM isotype on B12 levels was observed. Sixty seven percent (264) of the patients received thalidomide in combination with chemotherapy. Levels of B12 did not affect the development of grade ≥ 2 neuropathy after thalidomide treatment (p=0.49). No significant association was observed between serum B12 and the radial T- and Z score at bone densitometry (n= 270). There was a highly significant correlation between serum B-12 and ALP levels (correlation coefficient 0.25, p < 0.0001).Conclusions: Laboratory B12 deficiency was not common in our series of newly untreated MM patients. B12 levels did not predict the development of thalidomide-related neuropathy, nor are they associated with reduced bone density. The most striking finding of our study was a highly significant correlation between serum B12 and ALP concentrations; clinical significance of this observation requires further evaluation.

The ADVIA Centaur infectious disease assays: a technical review.

Bayer Healthcare, Diagnostics Division, has developed several new several new assays for hepatitis B, hepatitis C and HIV 1/O/2 on the ADVIA Centaur Immunoassay system. The panel for detection of markers for hepatitis B infection includes assays for hepatitis B surface antigen (HBsAg) and HBsAg. Confirmatory, antibodies to hepatitis B surface antigen (anti-HBs), IgM and IgG antibodies to hepatitis B core antigen (anti-HBc Total) and IgM antibodies to hepatitis B core antigen (anti-HBc IgM). The hepatitis B panel is complemented by third generation assays for anti-HCV and anti-HIV that concomitantly detects HIV-1 (including group O) and HIV-2. The features of the ADVIA Centaur and the design of the assays combine to deliver state-of-the-art performance. Features, such as disposable sample pipette tips to prevent sample carryover, clot detection and management to verify sample addition, reagent integrity checks to assure accurate reagent addition, auto repeat capabilities and the capacity to maintain up to 30 assays onboard at 2-8 degrees C all contribute to the systems's utility for infectious disease testing. Furthermore, the flexibility of the ADVIA Centaur has allowed for selection of formats to provide optimal assay performance. The anti-HBs, anti-HBc Total and anti-HIV 1/O/2 assays are antigen-bridging assays. The anti-HBc IgM assay is a class-capture two step assay configured for detection of IgM anti-HBc antibodies during acute HBV infection. The anti-HCV assay is an indirect assay utilizing streptavidin-coated microparticles preformed with a combination of recombinant and synthetic peptide antigens from the NS2, NS4, NS5 and core regions of the HCV genome. The HBsAg assay is a sandwich assay with an incubation time of 28 minutes and the HBsAg Confirmatory assay is a fully automated neutralization assay. The availability of these assays on the ADVIA Centaur Immunoassay system enables laboratories to consolidate other immunoassays along with the infectious disease assays for workstation operation and efficiencies.

The ADVIA Centaur immunoassay system--designed for infectious disease testing.

The ability to automate immunodiagnostics testing is critical for the efficiency of clinical laboratories. For automation of Infectious Disease testing, special design considerations must be made to ensure the integrity of the testing result while at the same time delivering productivity. The ADVIA Centaur was designed with the intent of performing a complete Infectious Disease panel including HBV, HCV, and HIV markers. Features such as disposable sample tips, sample and reagent delivery verification, and clog and clog detection have been incorporated in the design for assay robustness. Productivity features deliver best in class throughput performance for the Infectious Disease assays. Moreover, the underlying technology incorporating flexible assay protocols, universal solid phases and proprietary acridinium ester technology contribute to the assay design flexibility and analytical performance of the ADVIA Centaur immunoassay system.

Application of vitamin B 12-targeting site on Lactobacillus helveticus B-1 to vitamin B 12 assay by chemiluminescence method

Lactobacillus helveticus B-1 is assumed to have a vitamin B 12-targeting (or B 12-binding) site on the cells, since the binding reaction of vitamin B 12 with L. helveticus B-1 cells proceeded instantly and quantitatively. This reaction is specific to complete B 12 compounds, cobalamins, and can be used for a vitamin B 12 assay method by chemiluminescence. The calibration graph was linear from 0.1 to 10.0 ng/mL. The B 12 contents in oyster and sardine were 75.9 and 39.4 μg/100 g , respectively. These values were very close to those obtained using a chemilumi-ADVIA Centaur immunoassay system with intrinsic factor and to those obtained by microbiological assays.

Interaction between heparin and cardiac troponin T and troponin I from patients after coronary bypass surgery

Objectives: Heparin is thought to play a crucial role in the clinical monitoring of patients with acute coronary syndrome as well as after coronary bypass surgery in that it interferes with different commercial immunoassay test systems for cardiac troponin T (cTnT) and troponin I (cTnI). The mechanism, however, by which heparin apparently affects the cTnT and cTnI levels in plasma is not yet resolved. Design and methods: We analyzed the effect of heparin by simultaneously collecting serum and heparin plasma samples from 32 patients after coronary bypass surgery. The cTnT and cTnI levels were determined using the Roche/Elecsys, the Dade-Behring/Opus and the Bayer/ACS:Centaur immunoassay systems in the absence or in the presence of either heparinase or protamine. Association between the cardiac troponins and the anticoagulant has been demonstrated by affinity chromatography using heparin as the ligand. Results: The data obtained indicate that heparin produces an apparent decrease in cTnT as well as of cTnI levels, analyzed either by the Elecsys, the Opus or the ACS:Centaur immunoassay systems. Individual patients show a wide variation in the discrepancies between serum and heparin plasma troponin especially in the cTnT immunoassay. Pretreatment of the heparin plasma samples either with heparinase or protamine cannot completely reverse the heparin-induced decrease in cTnT and cTnI levels and therefore addition of these reagents to the commercial test systems could not significantly improve the performance of the assay. When serum is supplemented with increasing concentrations of heparin, and cardiac troponin levels were reanalysed, significantly lower recoveries for the cTnT than for the cTnI immunoassays were detectable. Affinity chromatography with heparin Sepharose demonstrates that cTnT and cTnI interact differentially with the negatively charged ligand. Whereas cTnI shows minor affinity to the immobilized heparin and is eluted at near physiological conditions, cTnT is bound and can be quantitatively recovered only by solutions of high ionic strength. Conclusions: We conclude, therefore, that the apparent decrease in cTnT values by addition of heparin is a result of direct molecular interaction between the negatively charged glycosaminoglycan and clusters of basic residues within the sequence of the cardiac protein. In contrast, the effect of heparin on the cTnI immunoassay systems, is primarily indirect, most possibly induced by changes within the sample matrix itself.