Stand-alone Test Research Articles

Structural magnetic resonance imaging for the early diagnosis of dementia due to Alzheimer's disease in people with mild cognitive impairment.

Structural magnetic resonance imaging for the early diagnosis of dementia due to Alzheimer's disease in people with mild cognitive impairment.

Microwave interferometer for phase and response time measurements.

We report the development of a microwave interferometer using a quadrature intermediate frequency (IQ) mixer designed to measure the relative phase change and response time of microwave devices tested in the Ka and upper K bands (22-40 GHz). The interferometer is currently used to test liquid crystal based devices. The system allows for the application of an AC bias beyond the amplitude/frequency limitations imposed on vector network analyzer bias ports. Our IQ mixer based design uses bias signals ranging from 0 to 100 V peak-to-peak in a frequency range from DC to 100 kHz. This range of bias signals is necessary to properly test the response of microwave devices designed with liquid crystal materials. The setup enables us to measure changes in the output phase of the device as a function of both the voltage and frequency of the applied bias signal. The setup also measures the phase difference as a function of microwave frequency and response times for the device under test. Our system can be integrated into a stand-alone test setup without the need for a vector network analyzer.

Optimizing Screening for HIV.

BackgroundThe HIV epidemic is unevenly distributed throughout the United States, even within neighborhoods. This study evaluated how effectively current testing approaches reached persons at risk for HIV infection across San Diego (SD) County, California.MethodsHIV case and testing data, sexually transmitted infection (STI) data, and sociodemographic data for SD County were collected from the SD Health and Human Services Agency and the “Early Test” community-based HIV screening program between 1998 and 2016. Relationships between HIV diagnoses, HIV prevalence, and STI diagnoses with screening at the ZIP code level were evaluated.ResultsOverall, 379 074 HIV tests were performed. The numbers of HIV tests performed on persons residing in a ZIP code or region overall strongly correlated with prevalent HIV cases (R2 = .714), new HIV diagnoses (R2 = .798), and STI diagnoses (R2 = .768 [chlamydia], .836 [gonorrhea], .655 [syphilis]) in those regions. ZIP codes with the highest HIV prevalence had the highest number of tests per resident and fewest number of tests per diagnosis. Even though most screening tests occurred at fixed venues located in high-prevalence areas, screening of residents from lower-prevalence areas was mostly proportional to the prevalence of HIV and rates of new HIV and STI diagnoses in those locales.ConclusionsThis study supported the ability of a small number of standalone testing centers to reach at-risk populations dispersed across SD County. These methods can also be used to highlight geographic areas or demographic segments that may benefit from more intensive screening.

How POCUS picks up a rare mimickers of acute appendicitis in the emergency department

BackgroundAppendicitis is the most common surgical abdominal emergency. Punctual diagnosis and rapid operative treatment of acute appendicitis are critically important, as it reduces the risk of complications, associated with greater morbidity and cost of care. The clinical diagnosis of acute appendicitis can be difficult and confusing. Due to some typical presentation and mimic, several abdominal conditions are left undiagnosed. POCUS has comparatively acceptable sensitivity and high specificity for diagnosing acute appendicitis, and early practice POCUS has a standalone test to rule out acute appendicitis.Case presentationA 43-year-old man presented with a 3-day history of abdominal pain rated 5/10 in intensity which had localized to the right iliac fossa by the time he attended our emergency. He described the acute pain as sharp in nature, colicky without the presence of any radiation. The pain was associated with nausea, but there was no vomiting. On clinical examination, the patient was stable at first, had a normal temperature with tenderness and guarding the right iliac fossa under nearby normal laboratory investigation.ConclusionThe importance of POCUS in scanning right iliac fossa for patients present with signs and symptoms that are mimicking acute appendicitis for diagnosing a rare pathology and avoiding the risk of ionizing radiation hazards and unnecessary surgical intervention.

Role of Laparoscopy in the Diagnosis of Genital TB in Infertile Females in the Era of Molecular Tests

To assess diagnostic value of polymerase chain reaction (PCR) in endometrial aspirates (EAs) in comparison with conventional tests for diagnosis of female genital tuberculosis (TB) and to find agreement between EA PCR done for endometrial TB and laparoscopic findings of pelvic TB in women with unexplained infertility. Prospective observational cohort study. Tertiary care hospital. A total of 732 infertile females screened and 385 enrolled to undergo procedure to obtain EAs. EAs were tested by conventional tests (histopathology, acid-fast bacilli, Lowenstein-Jensen staining, liquid culture) and PCR for Mycobacterium tuberculosis. Patients with positive conventional tests were started on antitubercular treatment (ATT). Patients with negative conventional tests underwent laparohysteroscopy irrespective of PCR results to assess changes of tubercular infection in the pelvis. Peritoneal washings were also sent for liquid culture and PCR for TB, and suspicious lesions were biopsied at laparohysteroscopy. Findings at laparoscopy upgraded the diagnosis in these women. EAPCR results were analyzed to find agreement with the findings at laparoscopy. Conventional tests were positive in 8 of 385 (2%) patients. PCR was positive in 58.1% (n = 224) of endometrial samples, with sensitivity of 62.5% (95% confidence interval [CI], 24.49-91.48), specificity of 41.91% (95% CI, 36.88-47.07), positive predictive value of 2.23% (95% CI, 1.31-3.78), negative predictive value of 98.14% (95% CI, 95.53-99.24), and a diagnostic accuracy of 42.34% (95% CI, 37.35-47.45) with conventional tests. A total of 265 patients underwent laparoscopy, of whom 165 were PCR positive and 100 were PCR negative. Laparoscopic findings suggestive of TB were found in 39.3% of patients who were PCR positive and 9% of patients who were PCR negative. Kappa agreement was 0.25, suggesting fair agreement between PCR and laparoscopy. PCR as a stand-alone diagnostic test for endometrial TB is not justified to confirm diagnosis and initiate ATT. The addition of laparohysteroscopy improves diagnostic yield for genital TB. Referring patients with a suspicion of female genital TB to tertiary care for 1-time laparoscopy is better than initiating ATT solely on the basis of PCR results.

Advanced ultrasound techniques in small animal reproduction imaging.

Ultrasonography is the imaging technology of choice for the evaluation of the reproduction system and of pregnancy in both humans and animals. Over the past 10years, there have been significant technological improvements of the equipment, while new technologies have been developed. Doppler, contrast-enhanced ultrasonography, elastography, and 3D/4D ultrasonography are advanced ultrasound techniques that have been designed as methods to increase the diagnostic sensitivity of two-dimensional (b-mode) ultrasound, and not as stand-alone tests. The basic physics as well as the advantages and limitations of these advanced ultrasound methods are briefly described. In the reproductive diagnostics of small animals, these techniques have gained an increased popularity as proved by the increased publication of several reports that are also briefly summarized in this review. Clinical applicability is to date limited because of a lack of research on the diagnostic value in concrete situations. Future research projects should focus also on standardization of the used techniques, on determination of thresholds to discriminate between healthy or diseases or fertile versus infertile and on the predictive value of advanced ultrasound findings. Continuing development and optimization of different ultrasound techniques as well as the increase of related scientific interest and worldwide research promises that the clinical interest on the use of advanced ultrasound techniques will increase in future.

It's Time to Reconsider The Principles of Humane Experimental Technique.

In the 60 years since the publication of The Principles of Humane Experimental Technique, the Three Rs (Reduction, Refinement, Replacement) proposed by William Russell and Rex Burch have gradually been accepted throughout the world as ways of facing up to the ethical and scientific dilemmas involved in animal experimentation. However, the scale of animal use and the use of animals as models of humans has continued, seemingly almost unchallenged in much of the scientific community, despite the warnings about models, species differences and human variation spelled out in the The Principles. In this Comment, it is proposed that it is time to move away from the animal welfare focus of the Three Rs, in favour of a wider concept of humanity, which also embraces human welfare. In addition, since less than 10% of new drugs successfully pass from preclinical testing, which is highly reliant on animal procedures, to acceptance for clinical use, it is argued that the aim should not be to directly replace animal testing with non-animal methods with similar aims and which produce similar results, but to take advantage of developments in cell and molecular biology and in computer science, to devise new, different, appropriate, specific and intelligent stand-alone preclinical testing strategies that are applicable to particular human situations.

Realisation and assessment of a low-cost LED device for contact lens disinfection by visible violet light.

This study presents a device for efficient, low-cost and eye-friendly overnight disinfection of contact lenses by visible violet light as an alternative to disinfection with biocide-containing solutions. Bacterial solutions with one Pseudomonas and one Staphylococcus strain each were irradiated for up to 8 h in commercial transparent contact lens cases by the presented light-emitting diode (LED) device. Samples were taken at different intervals and distributed on agar plates. The surviving bacteria were determined by counting of colony-forming units and compared to the specific requirements of the stand-alone test for contact lens disinfection of the hygiene standard ISO 14729. The concentration of both microorganisms was reduced by three orders of magnitude after less than 4 h of irradiation. The LED current and intensity have not yet been at maximum and could be further increased if necessary for other microorganisms. The presented device fulfils the requirement of the stand-alone test of the contact lens hygienic standard ISO 14729 for the tested Pseudomonas and Staphylococcus strains. According to literature data, the inactivation of Serratia marcescens, Candida albicans and Fusarium solani seems also possible, but may require increased LED current and intensity.

Лазерное зажигание топлива жидкий кислород — газообразный водород в крупноразмерной камере сгорания

The article presents a review of the results of studies of laser ignition of a cryogenic mixture (gaseous hydrogen and liquid oxygen) in an experimental combustion chamber, carried out at the bench testing facility of KBKhA (Voronezh). A laser ignition module specially designed at the Keldysh Research Centre and with parameters optimized for use in the rocket engine launch system was used during the experiments. Fuel ignition by the laser system occurred directly in the experimental chamber without the use of an ignition device or pre-chamber. To implement this ignition method, inflammation of the fuel in the chamber was carried out by focusing the laser radiation into the mixture, with the initiation of a spark of optical breakdown in the selected area with conditions favorable for the start of combustion. The results of the experiments confirmed the efficiency of the laser module during both standalone and firing tests, including multiple launches of the propulsion unit operated on a cryogenic mixture (gaseous hydrogen and liquid oxygen).

Development of a composite PVT panel with PCM embodiment, TEG modules, flat-plate solar collector, and thermally pulsing heat pipes

An integrated, multi-layered, composite photovoltaic thermal (PVT) module consisting of a multitude of stand-alone mini PVT cartridges was developed and a prototype was tested. Individual PVT cartridges consist of several sandwiched layers with photovoltaic cells, TEG units, packed-bed PCM layer for thermal storage, and thermally controlled heat pipes with dynamic control. These cartridges may be easily removed from the master PVT casing and re-installed for repair, inspection, and replacements. When cartridges are installed, the composite PVT module is completed by adding a flat-plate collector layer on the top. An internal array of pulse-control heat pipes maintains the total exergy output (power and heat) at a maximum by adjusting the heat flux. This PVT panel design eliminates the need for external thermal storage, pumping of the PVT coolant, and associated parasitic losses. PVT technology is made more energetically and exergetically rational as an economic asset for decarbonizing the environment. In such a configuration, it represents the solar equivalent of a conventional cogeneration system with a bottoming cycle. This paper summarizes the technological evolution of the new composite PVT system and provides examples of its use. Pilot-scale tests have shown that the Rational Exergy Management Model efficiency is about 25% more than a conventional PVT system and the total net electrical power output per unit solar insolation area is more than 30%. Total exergy output (power and heat) is twice as much as a conventional PVT unit in a typical summer month. The results obtained are discussed with further evolutionary recommendations. The importance of exergy-levelized unit panel cost is put forth to provide a basis for the fundamental procedure for a dedicated, well-accepted, and stand-alone PVT test method for the rating of system performance.

Evidence and recommendations for the use of segmental motion testing for patients with LBP – A systematic review

BackgroundAssessment of low back pain (LBP) includes segmental motion tests. Although often used in clinical practice, the validity, inter- and intra-rater reliability of such tests in individuals with LBP are not universally accepted, making it difficult to interpret findings in clinical practice. ObjectiveThe purposes of this study were to determine the validity and reliability of segmental motion tests for patients with LBP and to give reasoned recommendations for their use in practice. DesignSystematic review. MethodsA systematic literature research was conducted of databases PubMed, LIVIVO and Cochrane library. The included studies were appraised for quality by using QUADAS-2 and an adapted version of QAREL tools. Results of studies were appraised to give reasoned recommendations taking quality criteria into account. ResultsThirteen studies were included covering passive accessory intervertebral motion testing (PAIVMs), passive physiological intervertebral motion testing (PPIVMs) and the prone instability test (PIT). The risk of bias of studies ranged from high to low. When used in isolation, specificity of PAIVMS and PPIVMs was generally high and sensitivity poor. Reliability was overwhelming poor for both. Reliability of the PIT was inconsistent. None of these assessments can be strongly recommended when used in isolation. ConclusionThe evidence regarding validity and reliability of segmental motion testing is poor and clinical use of stand-alone tests cannot be recommended. Superiority of the combination of tests as a test battery or with other clinical information needs further investigation.

2373. Impact of a Change in Testing Strategy for Clostridioides difficile Infection on a Publicly Reported Metric and Treatment Days of Therapy

BackgroundIn an effort to optimize diagnostic testing for Clostridioides difficile infection (CDI) our health system changed from stand-alone PCR testing to a “2-step” approach wherein all positive PCR results reflexed to an EIA. We report the effects of this change on publicly reported CDI metrics and treatment days of therapy (DOT).MethodsThe setting includes 10 Cleveland Clinic Health System hospitals in northeast Ohio and one in Florida. On June 12, 2018, 9 NE Ohio hospitals changed from PCR alone to PCR followed by EIA. Stand-alone PCR testing remained at one and GDH / EIA / PCR for discordant for another. Testing volumes were obtained from the microbiology laboratory. C. difficile LabID event SIRs were obtained from NHSN. Public reporting interpretative categories were identified based on SIR for second half of 2018. DOT for CDI agents were obtained from an antimicrobial stewardship database.ResultsAmong hospitals that changed strategy the volume of PCR testing and the percent PCR + was similar between time periods. EIA positivity ranged from 23% to 53%. 4/11 hospitals improved their public reporting category: 3/9 that changed testing strategy and 1/2 that did not (Table 1). Two of 3 that changed strategy and improved public reporting also had a decrease in DOT. DOT increased in the 2 hospitals that did not change strategy.ConclusionSix months after adopting a 2-step CDI testing strategy 7 of 9 hospitals had a lower SIR with 3 also demonstrating an improvement in public reporting category favorably impacting reputational and reimbursement risk for our healthcare system. CDI agent DOT was similar before and after the change. The impact of choice of test on publicly reported metrics demonstrates the difficulty of utilizing a proxy for hospital onset CDI, the CDI LabID event, as a measure of quality of care provided. Disclosures All authors: No reported disclosures.

1494. Clinical Factors Associated with a Positive C. difficile PCR Test

Background C. difficile infection (CDI) remains a significant cause of morbidity and mortality. The most appropriate clinical scenario for CDI testing is unclear. The IDSA/SHEA guideline recommends testing patients with unexplained new-onset ≥3 stools in 24 hours. This study sought to evaluate clinical factors associated with a positive C. difficile PCR test.MethodsWe conducted a retrospective cohort study of adults (age >18 years old) admitted to the University of Colorado Hospital for whom a C. difficile PCR, either as a standalone test or part of the Biofire® Filmarray® Gastrointestinal Panel (GI Panel), was ordered between October 1, 2015 and August 31, 2017. Data collected included time since admission to test order, hospital length of stay, history of CDI, antibiotic use in the past 90 days, clinical presentation in the 24 hours preceding test order (fever, leukocytosis, number of stools), and laxative or antibiotic administration within 24 hours of test order. Multivariate logistic regression was used to evaluate the association of the above variables with having a positive C. difficile PCR test. If multiple tests were ordered during a single hospital encounter, only the first test was included in our analysis.Results3,070 tests were performed; of these, 72% were ordered in the first 72 hours of admission. Overall, 19% of tests were positive. After adjusting for clinical variables, patients with a prior history of C. difficile or who had received antibiotics in the past 24 hours were significantly more likely to have a positive test [OR 2.2 95% CI (1.54, 3.18) P < 0.0001] and [OR 16 95% CI (8.22, 31.41) P < 0.0001], respectively. Patients who used laxatives were significantly less likely to have a positive test [OR 0.75 95% CI (0.61, 0.91) P = 0.004]. The number of stools and presence of fever or leukocytosis were not significantly associated with a positive test.ConclusionPrior history of C. difficile and antibiotics use was highly associated with a positive C. difficile test, while laxatives use was associated with a negative test. The number of stools was not significantly associated with a positive C. difficile test, suggesting this may be less important clinical factor than previously believed; however, restricting testing in patients receiving laxatives is likely warranted.Disclosures All authors: No reported disclosures.

2357. Toxin Detection Using Single Molecule Counting Technology: The Best of Both Worlds?

BackgroundAccurate diagnosis of CDI remains challenging as there is no standalone laboratory test with adequate clinical sensitivity and specificity. Thus, many clinical laboratories currently employ a multistep algorithm incorporating a sensitive screening test followed by a specific toxin test. An automated ultrasensitive toxin immunoassay (Singulex Clarity® C. difficile toxins A/B assay) has demonstrated excellent performance compared with cell cytotoxicity neutralization assay (CCNA). In this study, the Clarity assay was evaluated relative to glutamate dehydrogenase (GDH), toxin EIA, toxin B gene PCR, multistep algorithms, and C. difficile culture with ribotyping.MethodsResidual clinical stool samples (n = 293) were collected from patients with suspected CDI. The samples were tested on-site with GDH (C. DIFF CHEK™-60), PCR (EntericBio realtime® C. difficile assay), a membrane-type toxin EIA (Tox A/B Quik Chek®), and culture and ribotyping. In total, 188 samples were tested with GDH and 239 samples were tested by PCR. All PCR-positive samples (n = 148) and prospectively tested GDH samples (n = 97) were tested with the toxin EIA. Culture and ribotyping information were available for 205 samples.ResultsThree of the samples tested gave no result using the Clarity assay and were excluded from the analysis. The Singulex Clarity C. difficile toxins A/B assay had high positive percent agreement (PPA) and low negative percent agreement (NPA) compared with toxin EIA and multistep algorithms ending with toxin EIA. The Clarity assay had high NPA and low PPA compared with PCR, GDH, and the multistep algorithm ending with PCR (figure). Less than 70% of the detected C. difficile PCR positive samples had toxins present. There was no difference in toxin concentration between the ribotypes.ConclusionThe Clarity assay had strong PPA compared with toxin EIA and strong NPA compared with PCR. The low NPA and PPA compared with toxin EIA and PCR, respectively, may reflect the poor sensitivity of current toxin EIAs and low specificity of PCR. The Clarity assay detected 30 different ribotype strains, and less than 70% of samples (by PCR) or strains (by ribotyping) had toxins present. The Clarity assay may be considered for use as a standalone test for CDI diagnosis. Disclosures All authors: No reported disclosures.

C-reactive protein kinetics post elective cranial surgery. A prospective observational study

Introduction: Post cranial surgery readmission, largely caused by surgical site infection (SSI), is a marker of patient-care quality requiring comprehensive discharge planning. Currently, discharge assessment is based on clinical recovery and basic laboratory tests, including C-reactive protein (CRP). Although CRP kinetics have been examined postoperatively in a handful of papers, the validity of CRP as a standalone test to predict SSI is yet to be explored.Methods: A prospective observational study was performed on adult patients undergoing elective cranial surgery over a 3-month period. Laboratory data; CRP, white cell count (WCC), neutrophil cell count (NCC), and clinical data were assessed pre and post-operatively and were evaluated as predictors for safe discharge. Readmission rates within 1 month were recorded.Results: In this study, 68 patients were included. About 8.6% were readmitted due to SSI. A postoperativepeak in CRP was seen on day 2 with a value of 57 in the non-readmitted group, and 115 in the readmitted group. CRP dropped gradually to normal levels by day 5 in the non-readmitted group. A secondary CRP rise at day 5 was noted in the readmitted group with a sensitivity, specificity, and negative predictive value of 71%, 90%, and 96%, respectively. Interestingly, our ROC analysis indicates that a CRP value of less than 65 predicts safe discharge with a sensitivity of 86%, specificity of 89% and negative predictive value of 98% of safe discharge (area under the curve, AUC: 0.782). No significant difference in other inflammatory markers was found between both groups.Conclusions: CRP increases postoperatively for 4–5 d which could be a physiological response to surgery, however, prolonged elevation or a secondary increase in CRP may indicate an ongoing infection. Our data validate the potential use of CRP levels to predict SSI. A multicentre study is warranted to investigate the role of CRP in predicting SSI.

1489. Clinical Utility and Patterns of the use of the Gastrointestinal PCR Panel Over a 2-Year Period at a University Hospital

BackgroundUp to 80% of cases of acute infectious gastroenteritis do not have an identifiable etiologic agent. Molecular syndromic diagnostic panels, such as the Biofire® Filmarray® gastrointestinal (GI) panel, can improve pathogen detection, including frequent causes of community-onset diarrhea. There are little data about the real-world use and test characteristics of the GI panel in the clinical setting. The objective of this study was to evaluate the patterns of use and clinical utility of the GI panel.MethodsWe conducted a retrospective cohort study of adults (age >18 years) admitted to the University of Colorado Hospital for whom a GI Panel was ordered from October 1, 2015 to August 31, 2017. Primary outcomes included patient demographics and co-morbidities, time since admission to test order, and cumulative test results. Descriptive statistics were utilized to summarize the frequencies of the primary outcome measures.Results1684 panels were ordered and completed during the study period compared with 1379 stand-alone C. difficile PCRs. Seventeen of the 22 components of the panel had been validated by our lab prior to the study period; therefore, results were only available for these pathogens. Most GI panels (78%) were ordered in the first 48 hours of admission, with 6% ordered between 48 and 72 hours after admission, and 16% >72 hours after admission. The GI panel yielded an organism 34% of the time. The most frequently identified organism was C. difficile (18.5%) followed by Norovirus (5.2%) and Enteropathogenic E. coli (5.1%).ConclusionOver a 2-year period at a University hospital, the GI panel only had a positive result in 20% of patients tested. Although most of the tests were ordered in the first 48 hours after admission, 22% were ordered after 48 hours, after which etiologies of hospital-onset diarrhea are expected to be more common. Among all GI Panel tests ordered, C. difficile was the most common organism identified, followed by Norovirus. Each of these organisms has an accurate and less costly alternative test. Stand-alone testing for C. difficile and Norovirus should be considered prior to the GI Panel for patients admitted to the hospital, particularly when admitted >48 hours.Disclosures All authors: No reported disclosures.

2360. Impact of a Two-Step Antimicrobial Stewardship Intervention on C. difficile Infection Diagnosis at an Urban Veteran’s Affairs Medical Center

Background C. difficile infection (CDI) is a common healthcare-associated infection and quality measure for hospitals. Diagnosis of CDI is challenging as testing modalities, i.e., nucleic acid amplification test (NAAT), are highly sensitive but cannot differentiate between colonization and infection. Therefore, judicious use of testing is critical to avoid unnecessary diagnosis and treatments.MethodsThis single-center, retrospective chart review evaluated the impact of a two-step diagnostic stewardship intervention on C. difficile diagnosis and use of oral vancomycin in the inpatient setting. For the first step of the intervention, providers were educated on appropriate diagnosis and treatment, and given access to an optional electronic CDI clinical decision support system (CDSS). For the second step of the intervention, the CDI NAAT stand-alone testing option was removed from the lab ordering menu and providers were required to use the CDSS to order testing. Clinical data including bed-days of care (BDOC), total number tests ordered, number of positive tests and use of oral vancomycin was collected for the pre-intervention period (1/1/16 – 3/31/17), post intervention period 1 (April 1, 2017–October 31/18) and post-intervention period 2 (November 1, 2018–March 31, 2019).ResultsCompared with the pre-intervention group, there were no significant differences in the number of total CDI NAATs ordered, positive CDI NAATs or vancomycin DOT/10,000 BDOC in post-intervention group 1. There was a reduction in the number of total CDI NAATs ordered (341 vs. 42 [87.7%]) and the number of positive CDI NAATs (56 vs. 7 [87.5%]) in post-intervention group 2, respectively. When this data were normalized based on bed days of care (BDOC), there were still significant reductions in NAATs ordered and number of positive CDI NAATs (64 vs. 27 [57.8%]; 11 vs. 5, respectively, [54.5%]) and with vancomycin oral DOT/10,000 BDOC (72 vs. 7 [90.3%]) (Table 1).ConclusionProvider education and an optional CDSS did not significantly impact CDI NAAT ordering or use of oral vancomycin for CDI. However, implementation of a mandatory CDSS for CDI testing was shown to significantly decrease the number of tests ordered, the number of positive tests, and the use of oral vancomycin. Disclosures All authors: No reported disclosures.

Clinical application of Aspergillus lateral flow device in bronchoalveolar lavage fluid of patients with classic risk factors for invasive pulmonary aspergillosis.

The diagnosis of invasive pulmonary aspergillosis (IPA) remains challenging. We evaluated the performance characteristics of a newly formatted Aspergillus lateral flow test, AspLFD, in bronchoalveolar lavage (BAL) fluid from patients with classic risk factors for IPA. Prospectively banked BAL samples from 14 patients with proven or probable IPA defined by EORTC/MSG criteria and 28 BAL samples from age-matched high-risk patients without IPA were tested with AspLFD according to manufacturer's directions. Results were read by two independent observers, and test performance was calculated. Age, gender and underlying risk factors, except for neutropenia and haematological malignancy, were similar between IPA cases and controls. Seven patients (50%) in the IPA group received a mould-active agent within 5days prior to bronchoscopy compared with only three patients (11%) in the control group, P=.004. Of 14 patients with proven/probable IPA, AspLFD was positive in 3 and negative in 9; two tests yielded invalid results. All 28 control patients had a negative AspLFD test. AspLFD showed low sensitivity (25%, 95% CI: 5.5% to 57.2%), but high specificity (100%. (95% CI: 87.7% to 100%). A positive AspLFD test in BAL fluid of patients with classic risk factors for IPA could be useful to support the diagnosis of proven/probable IPA because of its high specificity. However, as a stand-alone test for IPA, the use of AspLFD is limited by low sensitivity.

A Reconfigurable Radio-Frequency Converter IC in 0.18 µm CMOS

This work presents a reconfigurable RF converter for DVB-T television applications using triple-play over GPON. The system takes the DVB-T input, a wavelength division multiplexing (WDM) signal with spectral inversion in the range from 47 M Hz –1000 M Hz , up-converts its frequency to the band-pass of a highly selective surface-acoustic wave (SAW) filter centered at 1.3 G Hz , and then down-converts it so that it is compatible with the antenna input of conventional television sets. The designed RF converter incorporates two pairs of frequency synthesizer and mixer, based, respectively, on an integer-N phase-locked loop (PLL) with two LC-tank VCOs with 128 coarse tuning bands in the range from 1.35 G Hz –2.7 G Hz , and a double-balanced Gilbert cell, modified for better impedance matching and improved linearity. It is fed with regulated supplies compensated in temperature and programmed by an I 2 C interface operating on five 16-bit registers. This work presents the experimental characterization of the whole system plus selected cells for stand-alone testing, which have been fabricated in a 0.18 m CMOS process.

SC42 - Magnetic Resonance Imaging alone should not be considered as a stand-alone test for disease reclassification of men in Active Surveillance

SC42 - Magnetic Resonance Imaging alone should not be considered as a stand-alone test for disease reclassification of men in Active Surveillance