Commercial Diagnostic Test Research Articles

Cost effectiveness analysis of Oncotype DX testing in patients with synchronous unilateral primary breast cancer.

e12555Background: Oncotype DX is a commercial diagnostic test used to predict the likely benefit from chemotherapy in ER+ HER2- node- breast cancer. Patients with multiple, synchronous ipsilateral ...

Evaluation of the Xpert MTB/RIF assay for the diagnosis of smear-negative pulmonary and extrapulmonary tuberculosis in Madagascar

ObjectiveTo evaluate the feasibility of the implementation of a commercial rapid molecular diagnostic test (Xpert MTB/RIF) for the routine diagnosis of smear-negative or extrapulmonary tuberculosis (TB) and its diagnostic accuracy, and to assess HIV prevalence in a real-life setting in Madagascar. This study was set in a tertiary care hospital in Madagascar. MethodsA prospective cohort study was conducted of all consecutive cases with suspected smear-negative and/or extrapulmonary TB over a 2-year period. Cases were classified as proven, probable, or possible TB cases, or as having an alternative diagnosis. ResultsOf the 363 patients included, 183 (50.4%) had suspected smear-negative pulmonary TB and 180 (49.6%) had suspected extrapulmonary TB. For proven cases, the sensitivity, specificity, positive and negative predictive values of Xpert MTB/RIF were 82.4%, 98.8%, 98.3%, and 86.6%, respectively; for proven and probable cases grouped together, these values were 65%, 98.8%, 98.5%, and 64%, respectively. The diagnostic accuracy was slightly lower for extrapulmonary TB compared to smear-negative pulmonary TB. The prevalence of HIV infection was 12.1%, but almost half of these cases did not have TB (alternative diagnosis group). ConclusionsThe implementation of a rapid diagnosis programme for TB in a resource-poor setting is feasible. The performance of the Xpert-MTB/RIF was remarkable in this difficult-to-diagnose population. HIV prevalence in this study was much higher than the prevalence reported in the general population in Madagascar, in patients with TB and patients with conditions other than TB.

Abstract P2-10-10: Oncotype Dx testing in patients with synchronous unilateral primary breast cancer

Abstract Introduction: Oncotype DX, is a commercial diagnostic test that is used to predict the likely benefit from chemotherapy in ER+, HER2-negative, node-negative breast cancer. Patients with multiple, synchronous ipsilateral primary breast cancers often have >1 tumor tested if results from the first tumor show low or intermediate recurrence scores. Whether this approach is cost effective is unknown. Methods: We reviewed Oncotype Dx results for 907 ER+/HER2- breast cancer patients seen at Rush University Medical Center from 2/2006 to 10/2016. Thirty-nine patients (35 with the same histology) had multiple, synchronous unilateral tumor samples tested. Results were reported both on the numeric risk score associated with the test and the categorized result (low/intermediate/high) recurrence risk. For patients undergoing more than 2 tests, the first two were arbitrarily chosen for the paired analysis. Descriptive statistics were used to examine the risk score distributions and assess potential correlation between paired samples. Statistical inference methods included estimating the correlation coefficient, regression models predicting one score with another, and evaluating the paired score differences with respect to mean deviation from zero. For categorized risk score, analysis evaluating category concordance between tumors was used to assess the degree of agreement. Analyses were conducted on all patients, and a subset consisting of patients whose two tumors had the same histology, where scores may be expected to exhibit greater concordance. Results:Categorical risk score (RS): The concordance rate for risk category was 77% (30/39 patients) and Kendall's tau measure of association = 0.57, and was further increased to 80% (28/35 patients) and tau 0.63 for tumors with the same histology. Only one patient had tumor samples with low and high RS. A second patient had tumor samples with intermediate and high RS. Continuous RS: The correlation was 0.81 (p < 0.0001). For tumors with the same histology, correlation increased to 0.83, with regression r2 (predicting second tumor RS value with first) = 0.69, indicating that the majority of variation in second score can be explained by variation in first score. Conclusion: Oncotype Dx testing in patients with synchronous, unilateral primary breast cancers generally results in concordant results, even more so when the tumor samples are of the same histology. In our study, only 1 of the 39 patients had discordant low/high tumor pairs. Continuous scale tumor RS scores were highly correlated (> 0.8). Therefore the benefit of testing additional samples appears marginal and, with the $4,620 cost per test, may not be cost-effective. Citation Format: Clark M, Coggan J, Dignam J, Rao R, Usha L, Kabaker K, Cobleigh M. Oncotype Dx testing in patients with synchronous unilateral primary breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-10-10.

Clinical evaluation of the Abbott RealTime MTB Assay for direct detection of Mycobacterium tuberculosis-complex from respiratory and non-respiratory samples

Rapid and reliable diagnosis is crucial for correct management of tuberculosis. The Abbott RealTime MTB Assay represents a novel qualitative real-time PCR assay for direct detection of M. tuberculosis-complex (MTB) DNA from respiratory samples. The test targets two highly conserved sequences, the multi-copy insertion element IS6110 and the protein antigen B (PAB) gene of MTB, allowing even the detection of IS6610-deficient strains. We evaluated this commercial diagnostic test by analyzing 200 respiratory and, for the first time, 87 non-respiratory clinical specimens from our tertiary care institution and compared its results to our IS6110-based in-house real-time PCR for MTB as well as MTB culture. Overall sensitivity for Abbott RealTime MTB was 100% (19/19) in smear positive and 87.5% (7/8) in smear negative specimens, while the specificity of the assay was 100% (260/260). For both non-respiratory smear positive and smear negative specimens Abbott RealTime MTB tests showed 100% (8/8) sensitivity and 100% (8/8) specificity. Cycle threshold (Ct) value analysis of 16 MTB positive samples showed a slightly higher Ct value of the Abbott RealTime MTB test compared to our in-house MTB assay (mean delta Ct = 2.55). In conclusion, the performance of the new Abbott RealTime MTB Assay was highly similar to culture and in-house MTB PCR. We document successful analysis of 87 non-respiratory samples with the highly automated Abbott RealTime MTB test with no inhibition observed.

First report of Ralstonia pseudosolanacearum in the Lao PDR

Ralstonia pseudosolanacearum is reported for the first time from the Lao PDR. Typical symptoms of wilt and vascular exudate were observed in potatoes and tomatoes in Paksong district, Champasak province. Pathogenicity was proven and identification was based on symptoms, commercial diagnostic test kits and sequence of the egl gene.

Automatic time-lapse instrument is superior to single-point morphology observation for selecting viable embryos: retrospective study in oocyte donation

To correlate the different categories provided by a commercial diagnostic test with blastocyst formation, quality, implantation potential, and ongoing pregnancy (OPR) for the purpose of validating the automatic annotations and the classification algorithm. Observational, retrospective, multicenter cohort study. University-affiliated private IVF center. A total of 3,002 embryos, including 521 transferred embryos with known implantation, from 626 IVF cycles that were incubated in a conventional incubator and monitored with an automatic time-lapse test. None. Embryo selection was based on morphology and the classification provided by a commercial diagnostic test. Implantation was the primary end point, and OPR, blastocyst formation (BR), and embryo morphology were secondary end points. BR and number of optimal blastocysts were related to the classification test. This correlation was also observed when analyzing implantation rates (day 3 transfer: high 38.2%, medium 31.7% and low 26.1%; day 5 transfer: high 66.7%, medium 50%, low 31%). Patients where no high embryos were transferred (n = 75) had an OPR of 46.70%, and those patients where at least one high embryo was transferred (n = 109) significantly increased OPR to 67%. A logistic regression analysis studying other confounding factors (day of transfer, number of oocytes obtained, and embryo morphology classification) was included. In that model, if at least one of the embryos was labeled as high, OPR was 2.567 times higher than a cycle where no high embryos were transferred. Our study presents, to our knowledge, the largest set of transferred embryos after time-lapse analysis with the use of an automatic time-lapse test. The provided classification was related to reproductive outcome. Our results suggest that the automated embryo diagnostic test provided extra information to the embryologist to select the best embryos, independently from clinical features of the patient or day of transfer.

Background review for diagnostic test development for Zika virus infection.

ObjectiveTo review the state of knowledge about diagnostic testing for Zika virus infection and identify areas of research needed to address the current gaps in knowledge.MethodsWe made a non-systematic review of the published literature about Zika virus and supplemented this with information from commercial diagnostic test kits and personal communications with researchers in European preparedness networks. The review covered current knowledge about the geographical spread, pathogen characteristics, life cycle and infection kinetics of the virus. The available molecular and serological tests and biosafety issues are described and discussed in the context of the current outbreak strain.FindingsWe identified the following areas of research to address current knowledge gaps: (i) an urgent assessment of the laboratory capacity and capability of countries to detect Zika virus; (ii) rapid and extensive field validation of the available molecular and serological tests in areas with and without Zika virus transmission, with a focus on pregnant women; (iii) monitoring the genomic diversity of circulating Zika virus strains; (iv) prospective studies into the virus infection kinetics, focusing on diagnostic sampling (specimen types, combinations and timings); and (v) developing external quality assessments for molecular and serological testing, including differential diagnosis for similar viruses and symptom clusters. The availability of reagents for diagnostic development (virus strains and antigens, quantified viral ribonucleic acid) needs to be facilitated.ConclusionAn international laboratory response is needed, including preparation of protocols for prospective studies to address the most pressing information needs.

Prevalence of HBsAg and knowledge about hepatitis B in pregnancy in the Buea Health District, Cameroon: a cross-sectional study.

BackgroundAlthough infection with Hepatitis B Virus (HBV) remains a global public health problem, little is known about its epidemiology in pregnancy in sub-Saharan Africa. This study sought to determine the prevalence of, and identify factors associated with hepatitis B surface antigen (HBsAg) positivity among pregnant women in the Buea Health District (BHD) in rural Cameroon. We also assessed pregnant women’s knowledge about hepatitis B.MethodsA cross-sectional, descriptive study was undertaken. Participants were evaluated using a structured questionnaire with clinical examination and were then screened for HBsAg using a commercial rapid diagnostic test. Assessment of knowledge was done using a hepatitis B basic knowledge summary score.ResultsOf the 176 pregnant women studied, 9.7% (95% CI: 5.7%, 15%) tested positive for HBsAg. None of the risk factors assessed was significantly associated with HBsAg positivity. The hepatitis B knowledge summary score ranged from 0 to 12 with a mean of 1.5 (SD = 3.14, median = 0, IQR = 0 to 0). Only 16% of participants had scores greater than 6/12. The knowledge summary score of the participants was associated with the educational level (p-value = 0.0037).ConclusionThe high prevalence of HBsAg (9.7%) among women of child bearing age suggests that vertical transmission of HBV may be a public health problem in Buea Health District. Knowledge of HBV among pregnant women was poor. We recommend that all pregnant women ought to be routinely screened for HBV and that health education on HBV should be provided to pregnant women especially during antenatal visits.

Evaluation of Commercial Rapid Diagnostic Test Kit for Tuberculosis: Further Evidence Supporting Negative Policy on the Use of Serological Tests for Pulmonary Tuberculosis Diagnosis in Developing Countries

Aim: To know whether one of the commercially available immunochromatographic tuberculosis tests is comparable with the widely available method, direct sputum microscopy. Design: The study prospectively validated the pulmonary tuberculosis rapid test kit using the reference standard, Lowenstein Jensen culture and compared the outcome with the direct sputum microscopy. Place and Duration: The study was conducted in Zankli Medical Centre, Abuja, between November 2004 and July 2005. Original Research Article British Journal of Medicine & Medical Research, 4(2): 776-784, 2014 777 Methodology: 340 patients from direct observation therapy clinics located in six different government owned health facilities were referred to our facility. These patients; male (192) and female (148) were between the age of 10 and 64 years old. Three sputa samples were collected over two consecutive days and direct microscopy and culture were performed on these samples. Also, 4ml of blood were collected from the same patients for antibody detection using immunochromatographic technique. Results: The evaluated rapid diagnostic kit when compared with the reference standard has a sensitivity of 59.3% and 81.1% specificity. Sensitivity and specificity of direct microscopy, when compared with the rapid test is statistically significant (P=0.001); indicating diagnostic accuracy of the conventional method of pulmonary tuberculosis testing over the immunochromatographic test. Conclusions: The conventional test indicated high performance in this report and it is suggestive of the relevance and diagnostic accuracy of the widely available method in the diagnosis of pulmonary tuberculosis in developing countries. This assertion is also, supported by the 2008 WHO/TDR report on evaluation of nineteen tuberculosis rapid diagnostic kits.

Rapid and Highly Sensitive Method for Influenza A (H1N1) Virus Detection

In this study, we applied the developed paired surface plasma waves biosensor (PSPWB) in a dual-channel biosensor for rapid and sensitive detection of swine-origin influenza A (H1N1) virus (S-OIV). In conjunction with the amplitude ratio of the signal and the reference channel, the stability of the PSPWB system is significantly improved experimentally. The theoretical limit of detection (LOD) of the dual-channel PSPWB for S-OIV is 30 PFU/mL (PFU, plaque-forming unit), which was calculated from the fitting curve of the surface plasmon resonance signal with a S-OIV clinical isolate concentration in phosphate-buffered saline (PBS) over a range of 18-1.8 × 10(6) PFU/mL. The LOD is 2 orders of magnitude more sensitive than the commercial rapid influenza diagnostic test at worst and an order of magnitude less sensitive than real-time quantitative polymerase chain reaction (PCR) whose LOD for S-OIV in PBS was determined to be 3.5 PFU/mL in this experiment. Furthermore, under in vivo conditions, this experiment demonstrates that the assay successfully measured S-OIV at a concentration of 1.8 × 10(2) PFU/mL in mimic solution, which contained PBS-diluted normal human nasal mucosa. Most importantly, the assay time took less than 20 min. From the results, the dual-channel PSPWB potentially offers great opportunity in developing an alternative PCR-free diagnostic method for rapid, sensitive, and accurate detection of viral pathogens with epidemiological relevance in clinical samples by using an appropriate pathogen-specific antibody.

Influenza vaccination status is not associated with influenza testing among children: Implications for observational studies of vaccine effectiveness

Estimates of influenza vaccine effectiveness from observational studies that rely on physician-ordered influenza tests may be biased if physician testing behavior is influenced by patient vaccination status. To assess the potential for differential diagnostic testing of children by vaccine status, we examined the association between receipt of a commercial influenza diagnostic test and influenza vaccination among children aged 6–59 months who sought care at the Marshfield Clinic for acute respiratory or febrile illnesses during the 2004–05 through 2007–08 influenza seasons. There was no significant association between prior influenza vaccination and receipt of a diagnostic test for influenza. These findings suggest that estimates of vaccine effectiveness derived from observational studies among children are unlikely to be biased due to differential diagnostic testing.

Effects of feeding and induction strategy on the production ofBmR1 antigen in recombinantE. coli

To investigate the effects of feeding and induction strategies on the production of BmR1 recombinant antigen. Fed-batch fermentation was studied with respect to the specific growth rate and mode of induction to assess the growth potential of the bacteria in a bioreactor and to produce high yield of BmR1 recombinant antigen. Cells were grown at a controlled specific growth rate (mu(set)) during pre-induction, followed by constant feeding postinduction. The highest biomass (24.3 g l(-1)) was obtained during fed-batch process operated at mu(set) of 0.15 h(-1), whereby lower mu(set) (0.075 h(-1)) gave the highest protein production (9.82 mg l(-1)). The yield of BmR1 was increased by 1.2-fold upon induction with 1 mmol l(-1) IPTG (isopropyl-beta-d-thiogalactoside) compared to using 5 mmol l(-1) and showed a further 3.5-fold increase when the culture was induced twice at the late log phase. Combination of feeding at a lower mu(set) and twice induction with 1 mmol l(-1) IPTG yielded the best result of all variables tested, promising an improved method for BmR1 production. This method can be used to increase the production scale of the BmR1 recombinant antigen to meet the increasing demand for Brugia Rapid(), a commercial diagnostic test for detection of brugian filariasis.

Different levels of humoral immunoreactivity to different wheat cultivars gliadin are present in patients with celiac disease and in patients with multiple myeloma

BackgroundImmunity to food antigens (gliadin, cow's milk proteins) is in the centre of the attention of modern medicine focused on the prevention of diseases, prevention which is based on the use of appropriate restriction diet. Detection of the enhanced levels of the immune reactions to antigen(s) present in food is from this point of view of great importance because there are reports that some of health disturbances, like celiac disease (CD) and some premalignant conditions, like monoclonal gammopathy of undetermined significance (MGUS), were vanished after the appropriate restriction diets.It is well known that gliadin is toxic to small bowel mucosa of relatively small population of genetically predisposed individuals, who under this toxic action develop celiac disease (CD). As the quantity of immunogenic gliadin could vary between different wheat species, the first aim of this work was to determine the percentage of immunogenic gliadin in ten bread wheat cultivars and in three commercially grown durum wheat cultivars. The second part of the study was initiated by results of previous publication, reporting that sera of some of multiple myeloma (MM) patients showed the presence of elevated levels of anti-gliadin IgA, without the enhanced levels of anti-gliadin IgG antibodies, determined with commercial ELISA test. It was designed to assess is it possible to reveal is there any hidden, especially anti-gliadin IgG immunoreactivity, in serum of mentioned group of patients. For this purpose we tested MM patients sera, as well as celiac disease (CD) patients sera for the immunoreaction with the native gliadin isolated from wheat species used for bread and pasta making in corresponding geographic region.ResultsGliadin was isolated from wheat flour by two step 60% ehanolic extraction. Its content was determined by commercial R5 Mendez Elisa using PWG gliadin as the standard. Results obtained showed that immunogenic gliadin content varies between 50.4 and 65.4 mg/g in bread wheat cultivars and between 20 and 25.6 mg/g in durum wheat cultivars.Anti-gliadin IgA and IgG immunoreactivity of patients' sera in (IU/ml) was firstly determined by commercial diagnostic Binding Site ELISA test, and then additionally by non-commercial ELISA tests, using standardized ethanol wheat extracts -gliadin as the antigen.In both patients groups IgA immunoreactivity to gliadin from different cultivars was almost homogenous and in correlation with results from commercial test (except for one patient with IgA(λ) myeloma, they were more then five times higher). But, results for IgG immunoreactivity were more frequently inhomogeneous, and especially for few MM patients, they were more then five times higher and did not correlate with results obtained using Binding Site test.ConclusionResults obtained showed different content of immunogenic gliadin epitopes in various species of wheat.They also point for new effort to elucidate is there a need to develop new standard antigen, the representative mixture of gliadin isolated from local wheat species used for bread production in corresponding geographic region for ELISA diagnostic tests.

Comparison of methods for the determination of antimicrobial resistance in Campylobacter spp. human and the food chain isolates

With a microdilution method, using the commercial diagnostic test Sensititre Susceptibility Plates for Campylobacter MIC (Trek Diagnostic Systems, Cleveland, OH, USA), disk diffusion and agar dilution method, resistance to six antimicrobial agents were examined in a reference strain <i>Campylobacter jejuni</i> ATCC 33560 and 73 thermo-tolerant isolates of <i>Campylobacter</i> spp. For the microdilution method and all tested antimicrobial agents, our determined values of microbiological breakpoints of resistant strains were suggested as the minimum inhibitory concentration (MIC<sub>R</sub>) for ciprofloxacin ≥ 0.5, erythromycin ≥ 4, gentamicin ≥ 4, nalidixic acid ≥ 32 and tetracycline ≥ 4 μg/ml. On the basis of our study results, strains resistant to clindamycin were MIC<sub>R</sub> ≥ 2 μg/ml for the dilution methods and a zone diameter R ≤ 16 mm for the disk diffusion method. Comparison of the results of the resistance examination, a microdilution method and disk diffusion method with the reference agar dilution method, showed that all compared methods yielded identical results with the exception of the resistance determination in erythromycin and nalidixic acid. The errors were mostly the result of the interpretation criteria for MIC<sub>R</sub> of agar dilution method and different conditions of cultivation used. However, the compared methods, provide results comparable with the reference method having greater convenience of measurement.

From Bedside to Bench to Bedside to Clinical Practice: An Odyssey with Irinotecan

An odyssey can be defined as “a long wandering and eventful journey” ([1][1]). Traveling together with many collaborators, from a National Cancer Institute–sponsored phase I trial to drug metabolism to genomics, we learned, over more than a decade, the essence of pharmacogenetics, a field with

Analysis of a quantitative PCR assay for CMV infection in liver transplant recipients: an intent to find the optimal cut-off value

Preemptive therapy required highly predictive tests for CMV disease. CMV antigenemia assay (pp65 Ag) has been commonly used for rapid diagnosis of CMV infection. Amplification methods for early detection of CMV DNA are under analysis. To compare two diagnostic methods for CMV infection and disease in this population: quantitative PCR (qPCR) performed in two different samples, plasma and leukocytes (PMNs) and using a commercial diagnostic test (COBAS Amplicor Monitor Test) versus pp65 Ag. Prospective study conducted in liver transplant recipients from February 2000 to February 2001. Analyses were performed on 164 samples collected weekly during early post-transplant period from 33 patients. Agreements higher than 78% were observed between the three assays. Optimal qPCR cut-off values were calculated using ROC curves for two specific antigenemia values. For antigenemia >or=10 positive cells, the optimal cut-off value for qPCR in plasma was 1330 copies/ml, with a sensitivity (S) of 58% and a specificity (E) of 98% and the optimal cut-off value for qPCR-cells was 713 copies/5x10(6) cells (S:91.7% and E:86%). Using a threshold of antigenemia >or=20 positive cells, the optimal cut-off values were 1330 copies/ml for qPCR-plasma (S 87%; E 98%) and 4755 copies/5x10(6) cells for qPCR-cells (S 87.5%; E 98%). Prediction values for the three assays were calculated in patients with CMV disease (9 pts; 27%). Considering the assays in a qualitative way, the most sensitive was CMV PCR in cells (S: 100%, E: 54%, PPV: 40%; NPV: 100%). Using specific cut-off values for disease detection the sensitivity, specificity, PPV and NPV for antigenemia >or=10 positive cells were: 89%; 83%; 67%; 95%, respectively. For qPCR-cells >or=713 copies/5x10(6) cells: 100%; 54%; 33% and 100% and for plasma-qPCR>or=1330 copies/ml: 78%, 77%, 47%, 89% respectively. Optimal cut-off for viral load performed in plasma and cells can be obtained for the breakpoint antigenemia value recommended for initiating preemptive therapy with high specificities and sensitivities. Diagnostic assays like CMV pp65 Ag and quantitative PCR for CMV have similar efficiency and could be recommended as methods of choice for diagnosis and monitoring of active CMV infection after transplantation.

Spectrum of anti-measles immunoglobulin G subclasses in convalescents after measles.

A simple semiquantitative method for measuring anti-measles IgG subclasses is developed on the basis of commercial diagnostic test system for measurements of anti-measles IgG and a kit of peroxidase-labeled monoclonal antibodies to human IgG subclasses. During the acute phase of the disease specific antibodies are presented mainly by IgG2 antibodies, while in subjects with a history of measles more than 10 years before 2 subgroups were detected, which responded by production of IgG2 or IgG1 subclasses.

IgE antibody in the serum--detection and diagnostic significance.

IgE antibody in the serum--detection and diagnostic significance.

Lyme disease.

Lyme disease.

Persistence in bovine mastitis of Staphylococcus aureus clones as assessed by random amplified polymorphic DNA analysis, ribotyping and biotyping

Staphylococcus aureus isolates (N = 40) from bovine mastitis were characterized by random amplified polymorphic DNA-PCR (RAPD-PCR), ribotyping and biotyping. The isolates were collected in the veterinary surveillance area of the Ambulatory Clinic, Faculty of Veterinary Medicine, University of Helsinki from 20 quarters during the acute phase of infection and from the same quarters 3 weeks after cessation of therapy. The aim of the study was to compare the S. aureus isolates taken from the same quarter at different times to verify persistence of virulent strains in infected quarters and to compare the discriminatory power of the diagnostic methods. Using all methods (except for a commercial diagnostic test), the paired isolates of S. aureus were identical. Results suggest that the chronic nature of S. aureus infections was due to the persistence of the original infective strain. More laborious ribotyping and the more convenient RAPD-PCR method produced identical results. The molecular methods differentiated the 40 isolates into 6 distinct genotypes. Biotyping produced partially identical results to RAPD and ribotyping. A commercial diagnostic test system identified only 3 S. aureus biotypes.