Confirmatory Test Results Research Articles

THE EPIDEMIOLOGY AND HEALTH SYSTEM IMPACT OF MEDIUM-CHAIN ACYL-COA DEHYDROGENASE DEFICIENCY AMONG AFFECTED CHILDREN AND THOSE WITH FALSE POSITIVE NEWBORN SCREENING RESULTS IN ONTARIO, CANADA

IntroductionLimited research has focused on the health system impact of rare genetic disorders, including inborn errors of metabolism (IEM). Investigating patterns of health services use and their association with social...

Optimization of the reflow soldering process with multiple quality characteristics in ball grid array packaging by using the grey‐based Taguchi method

PurposeReflow soldering is one of the most significant factors in determining solder joint defect rate. This study aims to introduce an innovative approach for optimizing the multiple performances of the reflow soldering process.Design/methodology/approachThis study aims to minimize the solder joint defect rate of a ball grid array (BGA) package by using the grey‐based Taguchi method. The entropy measurement method was employed together with the grey‐based Taguchi method to compute for the weights of each quality characteristic. The Taguchi L18 orthogonal array was performed, and the optimal parameter settings were determined. Various factors, such as slope, temperature, and reflow profile time, as well as two extreme noise factors, were considered. The thermal stress, peak temperature, reflow time, board‐ and package‐level temperature uniformity were selected as the quality characteristics. These quality characteristics were determined using the numerical method. The numerical method comprises the internal computational flow that models the reflow oven coupled with the structural heating and cooling models of the BGA assembly. The Multi‐physics Code Coupling Interface was used as the coupling software.FindingsThe analysis of variance results reveals that the cooling slope was the most influential factor among the multiple quality characteristics, followed by the soaking temperature and the peak temperature. Experimental confirmation test results show that the performance characteristics improved significantly during the reflow soldering process.Practical implicationsThe proposed approach greatly reduces solder joint defects and enhances solutions to lead‐free reliability issues in the electronics manufacturing industry.Originality/valueThe findings provide new guidelines to the optimization method which are very useful for the accurate control of the solder joint defect rate within components and printed circuit board (PCB) which is one of the major requirements to achieve high reliability of electronic assemblies.

Current status of HTLV-1 carrier in Japanese pregnant women

We examined the current status of human T-cell leukemia virus type 1 (HTLV-1) carrier in Japanese pregnant women, according to the results of HTLV-1 screening and confirmation tests of women who gave birth in Japan in 2011. We requested 2642 obstetrical facilities to provide information of HTLV-1 tests and 71.3% of them responded. Considering the response rate and the rate of implementation of confirmation tests, the number of HTLV-1 carrier in Japanese pregnant women was estimated to be 1620 (0.16%) per year.

Borrelia miyamotoiInfection Presenting as Human Granulocytic Anaplasmosis

The diverse tickborne infections of the northeastern United States can present as undifferentiated flu-like illnesses. In areas endemic for Lyme and other tickborne diseases, patients presenting with acute febrile illness with myalgia, headache, neutropenia, thrombocytopenia, and elevated hepatic aminotransferase levels are presumptively diagnosed as having human granulocytic anaplasmosis (HGA). To assign a cause for illness experienced by 2 case patients who were initially diagnosed with HGA but did not rapidly defervesce with doxycycline treatment and had no laboratory evidence of Anaplasma phagocytophilum infection. Case report. 2 primary care medical centers in Massachusetts and New Jersey. 2 case patients acutely presenting with fever. Identification of the causative agent by polymerase chain reaction and DNA sequencing. Molecular diagnostic assays detected Borrelia miyamotoi in the peripheral blood of both patients. There was no evidence of infection with other tickborne pathogens commonly diagnosed in the referral areas. One of the case patients may have had concurrent Lyme disease. The presence of B. miyamotoi DNA in the peripheral blood and the patients' eventual therapeutic response to doxycycline are consistent with the hypothesis that their illness was due to this newly recognized spirochete. Samples from tick-exposed patients acutely presenting with signs of HGA but who have a delayed response to doxycycline therapy or negative confirmatory test results for HGA should be analyzed carefully for evidence of B. miyamotoi infection.

The arginine stimulation test: timing of peak is not a helpful parameter in the diagnosis of growth hormone deficiency

A typical peak timing in the glucagon stimulation test has been reported as an indication of growth hormone (GH) deficiency. Other stimulation tests have not been evaluated. To evaluate the clinical usefulness of peak timing in the arginine stimulation test (AST) for growth hormone deficiency. Retrospective review of 199 ASTs from one center. Outcomes included correlation of peak times with (a) frequency of deficient peak; (b) growth velocity standard deviation scores (GVSDSs); (c) other evidence of pituitary pathology; (d) results of confirmatory clonidine test; and (e) response to GH treatment. The peak in 83/109 (76.14%) sufficient tests occurred at typical times vs. 45/72 (62.5%) deficient tests (p<0.05). GVSDS on GH treatment was greater among patients with typical timing in the AST compared with atypical timing (2.67 ± 0.59 vs. 0.46 ± 1.17, p=0.021). No other variable correlated significantly with AST timing. Timing of peak in the AST is not a clinically useful parameter.

Multi-centre evaluation of a phenotypic extended spectrum β-lactamase detection guideline in the routine setting

This study aimed to evaluate the routine setting performance of a guideline for phenotypic detection of extended spectrum β-lactamases (ESBLs) in Enterobacteriaceae, recommending ESBL confirmation with Etest or combination disc for isolates with a positive ESBL screen test (i.e. cefotaxime and/or ceftazidime MIC >1 mg/L or an automated system ESBL warning). Twenty laboratories submitted 443 Enterobacteriaceae with a positive ESBL screen test and their confirmation test result (74% Escherichia coli, 12% Enterobacter cloacae, 8% Klebsiella pneumoniae, 3% Proteus mirabilis, 2% Klebsiella oxytoca). Presence of ESBL genes was used as reference test. Accuracy of local phenotypic ESBL detection was 88%. The positive predictive value (PPV) of local screen tests was 70%, and differed per method (Vitek-2: 69%, Phoenix: 68%, disc diffusion: 92%), and species (95% K. pneumoniae-27% K. oxytoca). A low PPV (3%) was observed for isolates with automated system alarm but third-generation cephalosporin MICs <2 mg/L. Local ESBL confirmation had a PPV and negative predictive value (NPV) of 93% and 90%, respectively. Compared with centrally performed confirmation tests, 7% of local tests were misinterpreted. Combination disc was more specific than Etest (91% versus 61%). Confirmation tests were not reliable for P. mirabilis and K. oxytoca (PPV 33% and 38%, respectively, although NPVs were 100%). In conclusion, performance of Etests could be enhanced by education of technicians to improve their interpretation, by genotypic ESBL confirmation of P. mirabilis and K. oxytoca isolates with positive phenotypic ESBL confirmation, and by interpreting isolates with a positive ESBL alarm but an MIC <2 mg/L for cefotaxime and ceftazidime as ESBL-negative.

Prevalence of extended spectrum β- lactamases inKlebsiellapneumoniae in a tertiary care hospital.

Purpose: To know the prevalence of extended spectrum β- lactamases (ESBL) in multidrug resistant strains of Klebsiellapneumoniaefrom various clinical samples.Material and Methods: A total of 97 strains of Klebsiellapneumoniae were selected for the study, screened for ESBL and confirmed by phenotypic confirmatory disc diffusion test (PCDDT)Results: 92(94.84%) of isolates were resistant to one or more 3 rd Generation cephalosporins (3GC) and which were confirmed for ESBL production by using the PCDDTmethod.Conclusion: Our study shows high prevalence of ESBL production. PCDDT is a simple and cost effective test which can be done as a routine in our microbiology labs.

Laboratory diagnostic outcome applying detection criteria recommended by the Scientific and Standardization Committee of the ISTH on Lupus Anticoagulant

This study shows the diagnostic outcome of an APTT-based and two dRVVT-based commercial confirmatory integrated tests with the application of the recommendations by the Scientific and Standardization Committee (SSC) on Lupus anticoagulant (LA)/antiphospholipid syndrome (APS) of the International Society on Thrombosis and Haemostasis (ISTH) issued in 2009 concerning the cut-off values for the screening, mixing and confirmatory tests for the detection of LA and the mandatory need to perform mixing tests of patient plasma with pooled normal plasma. The study population included 565 patients collected from a large central coagulation laboratory, for which the attending physicians requested LA detection. One-hundred-six healthy subjects (HS) and 131 selected patients on oral anticoagulant therapy (OAT) were included as negative controls. The results suggest that the performance of mixing tests is indicated for those methods with relatively poor specificity, but is less needed for those methods with high specificity. Furthermore, the SSC recommendation to use normal mid-value (i.e. the 50th percentile of distribution of results from healthy subjects) as the cut-off to interpret results of confirmatory tests, showed a modest increase in LA detection rate (sensitivity) but at the expense of specificity, particularly in methods with low specificity.

Investigation on performance and emissions of a biodiesel engine through optimization techniques

The study is aimed at investigating the effects of engine parameters on the performance and emission characteristics of a single cylinder 5.2 kW diesel engine. The experiments were designed using a statistical tool known as design of experiments based on taguchi. Five parameters, namely ,Power (P), Static injection pressure (IP), Injection timing (IT), Fuel Fraction (B) and compression ratio (CR) were varied at four levels and the responses brake power, fuel economy and emissions were investigated. The optimum n values of the response could be predicted using Signal - Noise ratio(S/N ratio) and optimum combination of control parameters were specified. Results of confirmation tests showed good agreement with predicted quantities. A compression ratio of 17.7, blend of 20% karanja biodiesel (B20), an injection pressure of 230 bar, injection timing of 27° bTDC and at 70% Load were found to be optimal values for the karanja biodiesel blended diesel fuel operation in the test engine.

Role of Ultrasonography (&amp;#147;Honeycomb Sign&amp;#148;) in Early Detection of Dengue Hemorrhagic Fever

Aim: This study was conducted to evaluate the early, specific ultrasonographic (USG) findings in clinically suspected dengue hemorrhagic fever (DHF) along with its prognostic value. Methods: From May 2009 to June 2012, 20 patients were referred with high-grade fever and abdominal pain. All the patients underwent immediate abdominal USG. A specific change – “Honeycomb” pattern in the thickened gallbladder (GB) wall (mostly in the fundal area) – on USG suggested the diagnosis of DHF, which was subsequently confirmed by serology in all patients. Treatment was stated on the bases of USG findings before the positive serology report. After starting treatment the USG on the 3rd day showed reduction in GB wall thickening, which was almost cleared by the 7th day in clinically improving patients. Results: All 20 patients had type-2 dengue fever, i.e., DHF Grades I and II, as confirmed after USG by platelet count and serologic tests. USG features included a much-thickened GB wall in all the patients, but showing a “Honeycomb” pattern (proposed as Sachar and Sunder’s sign) in 19 patients (95%), multilayered (laminated/onion peel) in 1 patient (5%), ascites in 15 patients (75%), splenomegaly in 8 patients (40%), and pleural effusion in 14 patients (70%). (Pleural effusion was either right-sided or bilateral, but never alone on the left side.) Conclusions: Abdominal emergency USG can be used as a first-line imaging modality in patients with suspected DHF to detect early signs that are suggestive of the disease prior to obtaining serologic confirmation test results, especially in a dengue fever epidemic area. Also, reducing GB wall thickness can be used as a prognostic sign in cases of DHF.

Optimization of diesel engine parameters using Taguchi method and design of evolution

The objective of this work is to optimize the control parameters of the direct injection (DI) single cylinder diesel engine with respect to NOx (Oxides of Nitrogen) and fuel emissions through experimental investigations and Taguchi method. A single cylinder 5.2 kW diesel engine was selected for this experiment. Five parameters such as clearance volume, valve opening pressure, nozzle-hole diameter, static injection timing and load torque were varied at four levels and the responses such as NOx emissions and fuel economy were recorded. The optimum values of the response variables could be predicted using S/N ratio and optimum combination of control parameters were specified. Results of confirmation tests showed good agreement with predicted results. Thus the relationship between the diesel engine operating parameters with NOx and b.s.f.c (brake specific fuel consumption) could be understood using Taguchi method of experimental design.

The Prevalence and Correlates of Receiving Confirmatory HIV Test Results Among Newly Diagnosed HIV-Positive Individuals at a Community-Based Testing Center

This study examined the prevalence and correlates of completing the HIV testing process-specifically receiving a confirmatory HIV test and returning for the results-in a sample of newly diagnosed HIV-positive individuals at an HIV testing center in New York City. Of the 213 individuals who received a reactive rapid HIV test result, 82% received a confirmatory HIV test. Of the 236 individuals who received a positive result on a rapid or traditional HIV test that was validated by a positive confirmatory HIV test, 65% returned for the confirmatory test results. Multivariate analyses revealed that being a non-U.S. citizen, homeless/living in transitional housing, being uninsured, and testing off-site were significantly associated with completing the HIV testing process. The findings indicate the need to explore strategies that address obstacles to receiving confirmatory HIV testing and returning for the results, in addition to the feasibility of a rapid confirmatory HIV test.

False-negative post-18-month confirmatory HIV tests in HIV DNA PCR-positive children

The WHO guidelines for children less than 18 months old diagnosed with HIV based on presumptive clinical diagnosis or one virologic test recommend confirmatory HIV antibody testing after 18 months of age. This study describes post-18-month HIV test results following this WHO-recommended confirmatory testing strategy. Case series and retrospective review of routine program data. Children enrolled at the Baylor Children's Clinical Center of Excellence, a pediatric and family HIV clinic in Maseru, Lesotho from December 2005 through January 2009 with a positive HIV DNA PCR at less than 18 months of age and HIV rapid test results after 18 months of age were included. Post-18-month confirmatory HIV test results are described. Factors associated with non-positive confirmatory rapid tests were determined using binary logistic regression. Of the 109 children meeting inclusion criteria, 22 (20.2%) had negative and 27 (24.8%) discordant confirmatory rapid tests. Forty-six of these 49 were on antiretroviral therapy (ART). Among these 49, 11 of 24 post-18-month HIV DNA PCRs were negative, whereas nine of 10 post-18-month HIV ELISAs were positive; 29 were definitively and 17 probably HIV-infected, two were uninfected, and one had undetermined status. Only age less than 9 months at ART initiation (odds ratio 4.25, P = 0.002) was associated with non-positive rapid tests. False-negative post-18-month confirmatory rapid tests and HIV DNA PCRs in children on ART are common, associated with early ART initiation, and may lead to inappropriate ART discontinuation and discharge from care of truly HIV-infected children.

Unresolved Discrepancies between Cannabinoid Test Results for Infant Urine

False-positive drug screen results for tetrahydrocannabinol (THC) have been observed. This study investigated the rate of unconfirmed positive screen results in infant and noninfant urine samples and evaluated possible reasons for differences. The rate of unconfirmed positive THC screen results for urine samples was determined retrospectively in 2 independent data sets (n = 14,859, reference laboratory; n = 21,807, hospital laboratory) by comparing positive immunoassay-based drug screen results with the associated results of confirmation tests. We then assessed the rate of positive THC screens for samples with varying likelihoods of cannabinoid presence to evaluate the contribution of infant-specific urine constituents to positive results. Finally, a method to detect a THC metabolite (11-hydroxy-Δ⁹-THC) that occurs in meconium was developed to determine its prevalence in infant urine. Positive screen results failed to confirm more frequently in samples from infants (47%) than in noninfants (0.8%). The hospital laboratory observed a similar discrepancy with a different immunoassay. Infant samples with a high likelihood of containing cannabinoids despite negative confirmatory results had a similar rate of positive screening results (50%, n = 20), whereas all samples with a low likelihood of containing cannabinoids screened negative (n = 23). 11-Hydroxy-Δ⁹-THC was not detected in any infant urine sample tested (n = 16). Conventional confirmatory methods for THC may be inappropriate for urine samples from infants. Our results suggest that one or more currently unrecognized THC-associated compounds are responsible for positive THC screen results for infant urine, as opposed to an infant-associated interference.

Childhood asthma in low income countries: an invisible killer?

Bacterial pneumonia has hitherto been considered the key cause of the high respiratory morbidity and mortality in children under five years of age (under-5s) in low-income countries, while asthma has not been stated as a significant reason. This paper explores the definitions and concepts of pneumonia and asthma/wheezing/bronchiolitis and examines whether asthma in under-5s may be confused with pneumonia. Over-diagnosing of bacterial pneumonia can be suspected from the limited association between clinical pneumonia and confirmatory test results such as chest x-ray and microbiological findings and poor treatment results using antibiotics. Moreover, children diagnosed with recurrent pneumonia in infancy were often later diagnosed with asthma. Recent studies showed a 10-15% prevalence of preschool asthma in low-income countries, although under-5s with long-term cough and difficulty breathing remain undiagnosed. New studies demonstrate that approximately 50% of acutely admitted under-5s diagnosed with pneumonia according to Integrated Management of Childhood Illnesses could be re-diagnosed with asthma or wheezing when using re-defined diagnostic criteria and treatment. It is hypothesised that untreated asthma may contribute to respiratory mortality since respiratory syncytial virus (RSV) is an important cause of respiratory death in childhood, and asthma in under-5s is often exacerbated by viral infections, including RSV. Furthermore, acute respiratory treatment failures were predominantly seen in under-5s without fever, which suggests the diagnosis of asthma/wheezing rather than bacterial pneumonia. Ultimately, underlying asthma may have contributed to malnutrition and fatal bacterial pneumonia. In conclusion, preschool asthma in low-income countries may be significantly under-diagnosed and misdiagnosed as pneumonia, and may be the cause of much morbidity and mortality.

Increased Need for Testing to Confirm Initial Weakly Reactive Results for Hepatitis B Virus Surface Antigen

Objectives: To examine the agreement between results of initial testing and those of confirmatory testing for the presence of hepatitis B virus surface antigen (HBsAg) via electrochemiluminescence immunoassay (ECLIA). This study also sought to evaluate the applicability of confirmatory testing for HBsAg detection via ECLIA and to establish the gray zone within which a confirmatory test is needed. Methods: Specimens collected between April 2009 and July 2010 that yielded COI values between 0.9 and 10.0 as determined by HBsAg ECLIA testing were subjected to confirmatory testing to evaluate the appropriate threshold for HBsAg confirmation. Receiver operating characteristic (ROC) analysis of the confirmatory test results were used to establish the COI gray zone for the initial test results, with the goal of determining when confirmatory testing is required. Results: Of the 144 specimens with COI values between 0.9 and 10.0, all of those with negative confirmatory testing results had COI values of 0.9 to 4.0. Specimens that required confirmatory testing had results within a COI gray zone range of 1.0 to 4.0 in HBsAg initial testing. Conclusion: Confirmatory testing to detect HBsAg is essential for specimens that produce weak initial HBsAg signals (ie, which had initial COI values of 1.0–4.0), as determined by ECLIA because the initial test results can include false positives. ROC analysis established a COI range for initial HBsAg test results providing the range of concentrations over which a confirmatory test is required. * HBV : hepatitis B virus CHB : chronic hepatitis B HBsAg : hepatitis B virus surface antigen ECLIA : electrochemiluminescence immunoassay COI : cutoff index S/CO : sample to cutoff S/N : counts per minute of sample/mean counts per minute of negative controls ROC : receiver operating characteristic

Evaluation of low-velocity impact response of honeycomb sandwich structures using factorial-based design of experiments

A response surface analysis of data from factorial experiments is used to determine the effect of different design factors on the low-velocity impact response of the honeycomb sandwich structures. A low-cost, out-of-autoclave manufacturing process is utilized to manufacture aerospace quality honeycomb sandwich panels. CYCOM® 5320 out-of-autoclave prepreg and FM® 300-2M are used as facesheet and adhesive, respectively. The out-of-autoclave process uses the vacuum bag pressure, thus, avoiding costly tooling and making the process more economical. A completely randomized design is used while manufacturing and testing the samples. Three design factors: angle difference between successive prepreg layers, number of prepreg layers, and number of adhesive layers, are selected as experimental variables. Each variable is considered at three levels, yielding a 33 factorial design. To investigate the effect of the experimental variables on the three response variables: energy absorbed (X); peak contact force (Y) and maximum deflection (Z), a low-velocity impact test is conducted. Analysis of variance and response surface techniques are used to analyze the data. The significant design factors for each response variable are identified using analysis of variance. Response surface analysis is carried out and the resulting regression models are employed to quantify the behavior of each of the response variables in response to changes in the design factors. The regression models are verified with the confirmation test results and both are in close agreement.

Drilling of micro-holes on copper using electrochemical micromachining

Electrochemical micromachining (EMM) is one of the best micromachining techniques for machining electrically conducting, tough, and difficult-to-machine materials with suitable machining parameter combinations. For the micro-fabrication of components like nozzle plate for ink jet printer head and delicate 3D electronic circuit board components, EMM is predominantly used. In this paper, the effect of process parameters such as such as electrolyte concentration, machining voltage, frequency, and duty cycle on the material removal rate (MRR) and overcut were studied using copper workpiece. According to Taguchi’s quality design concepts, an L18 orthogonal array is used. ANOVA is also performed to determine the most significant parameter that influences the EMM process. The optimum process parameters for lower overcut and higher MRR are found out and confirmation tests were carried out to validate the prediction. The confirmation test results show 19 and 20.78 % improvements of overcut and MRR, respectively, with respect to the initial parametric setting.

Recent advances in the diagnosis and treatment of influenza pneumonia.

A potentially fatal complication of influenza infection is the development of pneumonia, caused either directly by the influenza virus, or by secondary bacterial infection. Pneumonia related to the 2009 influenza A pandemic was found to be underestimated by commonly used pneumonia severity scores in many cases, and to be rapidly progressive, leading to respiratory failure. Confirmation of etiology by laboratory testing is warranted in such cases. Rapid antigen and immunofluorescence testing are useful screening tests, but have limited sensitivity. Confirmation of pandemic H1N1 influenza A infection can only be made by real-time reverse-transcriptase polymerase chain reaction (rRT-PCR) or viral culture. The most effective preventive measure is annual influenza vaccination in selected individuals. Decisions to administer antiviral medications for influenza treatment or chemoprophylaxis should be based upon clinical and epidemiological factors, and should not be delayed by confirmatory laboratory testing results. Neuraminidase inhibitors (NI) are the agents of choice.

Rapid HIV Testing in Large Urban Jails

HIV prevalence is higher in jails than in the community, yet many jails do not conduct HIV testing. Jails in Baltimore, Maryland; Philadelphia, Pennsylvania; and the District of Columbia have implemented innovative rapid HIV testing programs. We have summarized the results of these programs, including the numbers of persons tested, rapid and confirmatory HIV test results, and numbers of persons newly diagnosed with HIV. We have described facilitators and challenges of implementation. These programs confirmed that rapid HIV testing in jails was feasible and identified undiagnosed HIV infection. Challenges included limited space to provide confidential rapid HIV testing and rapid turnover of detainees. Implementation required collaboration between local governments, health agencies, and correctional institutions. These programs serve as models for expanding rapid HIV testing in jails.