Random Access Test Research Articles

Random access test as an identifier of nonclassicality* *This paper is dedicated to Stan Gudder.

Random access codes (RACs) are an intriguing class of communication tasks that reveal an operational and quantitative difference between classical and quantum information processing. We formulate a natural generalization of RACs and call them random access tests (RATs), defined for any finite collection of measurements in an arbitrary finite dimensional general probabilistic theory. These tests can be used to examine collective properties of collections of measurements. We show that the violation of a classical bound in a RAT is a signature of either measurement incompatibility or super information storability. The polygon theories are exhaustively analysed and a critical difference between even and odd polygon theories is revealed.

Improved molecular laboratory productivity by consolidation of testing on the new random-access analyzer Alinity m

Abstract Objectives Automated molecular analyzers have accelerated diagnosis, allowing earlier intervention and better patient follow-up. A recently developed completely automated molecular analyzer, Alinity™ m (Abbott), offers consolidated, continuous, and random-access testing that may improve molecular laboratory workflow. Methods An international, multicenter study compared laboratory workflow metrics across various routine analyzers and Alinity m utilizing assays for human immunodeficiency virus type 1 (HIV-1), hepatitis C virus (HCV), hepatitis B virus (HBV), high-risk human papillomavirus (HR HPV), and sexually transmitted infection (STI) (Chlamydia trachomatis [CT]/Neisseria gonorrhoeae [NG]/Trichomonas vaginalis [TV]/Mycoplasma genitalium [MG]). Three turnaround times (TATs) were assessed: total TAT (sample arrival to result), sample onboard TAT (sample loading and test starting to result), and processing TAT (sample aspiration to result). Results Total TAT was reduced from days with routine analyzers to hours with Alinity m, independent of requested assays. Sample onboard TATs for standard workflow using routine analyzers ranged from 7 to 32.5 h compared to 2.75–6 h for Alinity m. The mean sample onboard TAT for STAT samples on Alinity m was 2.36 h (±0.19 h). Processing TATs for Alinity m were independent of the combination of assays, with 100% of results reported within 117 min. Conclusions The consolidated, continuous, random-access workflow of Alinity m reduces TATs across various assays and is expected to improve both laboratory operational efficiency and patient care.

NeuMoDx random access molecular diagnostic system for detection and quantification of hepatitis B virus in clinical samples.

Currently, several molecular assays are available to detect and quantify HBV DNA in clinical samples. We aimed to characterize and compare the clinical performance of newly designed NeuMoDx PCR to the existing artus PCR. The plasma HBV DNA levels of 96 clinical and 5 external quality control samples were measured by NeuMoDx and artus assays simultaneously in Kocaeli University, Turkey. The linearity, agreement and the correlation between two assays were determined by Deming regression analysis, Bland-Altman plotting, the chi-square and the relative absolute error statistical analyzes. For all statistical analyzes, the XLSTAT statistical program was used. The mean (standard deviation; SD) age was 45.07 ± 12.29. HBsAg S/Co median (range) was 4,273.4 ± 1,138.1 and ALT U/L median (range) was 27 ± 16. The mean (SD) of HBV DNA was 1.46+E6 ± 1.0+E4 for NeuMoDx and 1.54+E5 ± 4.7 + E4 for artus assays. The Deming regression indicates a linear correlation (95% confidence). The chi-square test indicates strong correlation (p < 0.001). Bland-Altman analysis confirms that the measurement difference is acceptable. The relative absolute error analysis for artus showed relatively less and more consistent error rate. With 5 external quality check samples, the statistical significance was low (p = 0.566). The NeuMoDx HBV assay showed an excellent analytical performance by providing a rapid, high throughput technology in a random-access testing system in clinical samples and may be a new solution for viral load quantification in the management of HBV infections.

Investigating utilising the Alinity m platform to detect hepatitis C virus RNA in dried blood spot samples

Elimination of Hepatitis C virus (HCV) relies on increasing HCV diagnostic rates in hard to reach populations. Dried blood spot (DBS) samples are a convenient sample type for HCV testing, as they can be collected in non-traditional settings such as drug services and prison settings, increasing access to HCV testing. Herein we investigate an off-label DBS protocol for use on the Abbott Alinity m platform. A dilution series of HCV RNA positive blood was used to determine the analytical sensitivity of the test. We assess the sensitivity and specificity of HCV RNA detection in 50 mock DBS specimens compared to associated plasma viral load, and re-test 66 clinical DBS, previously tested on the m2000 to determine the clinical sensitivity and specificity of the assay. The dilution panel suggested that the Alinity m DBS assay is one log more sensitive than our current DBS HCV RNA assay. Mock DBS demonstrated 100% specificity, and 100% sensitivity for samples with plasma HCV RNA viral loads > 2.7 log10 IU/mL, however four samples with viral loads between 1.3 and 2.4 log10 IU/mL were not detected. The clinical sensitivity and specificity of previously tested DBS was 94% and 100% respectively, with two samples reported as low level RNA positive on the m2000 testing negative on Alinty m. The data suggests that DBS can be used as an off-label specimen type on the Alinity m HCV assay. Allowing continuous, random access testing of DBS simultaneously alongside other Alintiy m assays, potentially improving test turn-around times.

Fully Automated Molecular Diagnostic System \u201cSimprova\u201d for Simultaneous Testing of Multiple Items

Nucleic acid amplification-based diagnostics is known as one of the molecular diagnostic systems that allows higher sensitive detection of pathogens than test methods such as immunoassay. However, it has not been widely used because it is complicated to use and takes a long time to generate results. On the other hand, development of fully automated molecular diagnostic systems has been growing around the world as demand for such systems from physicians and laboratory technicians has increased. To meet this demand, we have developed the “Simprova” fully automated molecular diagnostic system, which takes advantage of LAMP (Loop-mediated Isothermal Amplification), a method Eiken Chemical Co., Ltd. invented. Simprova comprises a master unit that controls the entire system and a test unit that extracts and purifies nucleic acid from samples (pretreatment), and uses the LAMP method to detect and amplify nucleic acid. Users can obtain test results automatically by simply installing a pretreatment cartridge, a multi-well testing chip and the sample in the test unit. The multi-well testing chip has 25 reaction wells connected by channels and enables simultaneous testing of multiple targets with one sample. Turnaround time for one test is approximately 30 minutes. Since a conventional extraction and purification method using magnetic-bead separation is used for the pretreatment, nucleic acid can be extracted from serum, plasma, whole blood, urine, and sputum, for example. In addition, the system can perform random-access testing by connecting four test units to the master unit to realize near-the-patient testing. Simprova is therefore a robust and useful system for a wide variety of applications.

Prospective Evaluation of the mariPOC Test for Detection of Clostridioides difficile Glutamate Dehydrogenase and Toxins A/B.

The objective of this study was to evaluate a novel automated random-access test, mariPOC CDI (ArcDia Ltd., Finland), for the detection of Clostridioides difficile glutamate dehydrogenase (GDH) and toxins A and B directly from fecal specimens. The mariPOC test was compared with both the GenomEra C. difficile PCR assay (Abacus Diagnostica Oy, Finland) and the TechLab C. diff Quik Chek Complete (Alere Inc.; now Abbot) membrane enzyme immunoassay (MEIA). Culture and the Xpert C. difficile assay (Cepheid Inc., USA) were used to resolve discrepant results. In total, 337 specimens were tested with the mariPOC CDI test and GenomEra PCR. Of these specimens, 157 were also tested with the TechLab MEIA. The sensitivity of the mariPOC test for GDH was slightly lower (95.2%) than that obtained with the TechLab assay (100.0%), but no toxin-positive cases were missed. The sensitivity of the mariPOC test for the detection of toxigenic C. difficile by analyzing toxin expression was better (81.6%) than that of the TechLab assay (71.1%). The analytical specificities for the mariPOC and the TechLab tests were 98.3% and 100.0% for GDH and 100.0% and 99.2% for toxin A/B, respectively. The analytical specificity of the GenomEra method was 100.0%. The mariPOC and TechLab GDH tests and GenomEra PCR had high negative predictive values of 99.3%, 98.3%, and 99.7%, respectively, in excluding infection with toxigenic C. difficile The mariPOC toxin A/B test and GenomEra PCR had an identical analytical positive predictive value of 100%, providing highly reliable information about toxin expression and the presence of toxin genes, respectively.

1773. Development and Evaluation of an Automated Adenovirus Quantitative Assay Using the Luminex ARIES® System

BackgroundThe quantification of circulating human adenovirus (HAdV) DNA is the recommended diagnostic method to predict disseminated disease. Most current HAdV quantitative assays are manually performed and lack the flexibility needed to provide rapid answers when required.The purpose of this study was to evaluate the application of MultiCode® HAdV PCR assay for use with the Luminex ARIES® system (Luminex Corporation, Austin, TX) as an automated and random access test for the quantitative detection of HAdV DNA in plasma.MethodsAnalytical performance characteristics including assay limit of detection/quantitation (LoD/LoQ), accuracy, and inter-, intra-reproducibility were studied using commercial panels (Exact Diagnostics, Fort Worth, TX). Assay specificity was determined usingHAdV reference strains obtained from the American Type Culture Collection (Manassas, VA) and plasma spiked with related Herpes viruses and pathogens commonly found in the blood. Assay accuracy was verified with analysis of 30 plasma samples spiked with different concentrations of control material that covered the full range of HAdV DNA levels. We also prospectively analyzed 180 plasma samples collected from 102 patients. DNA from all samples were extracted, amplified and detected on a single automated Luminex ARIES® system.ResultsThe assay has a wide linear range from 2.55 to 9.4 log10 HAdV DNA copies/mL (coefficient of determination; R2 = 0.995) with a detection limit of 1.82 log10 (95% positivity rate), and a limit of quantification of 2.55 log10 copies/mL. The assay detected HAdV DNA from Adenovirus groups A-F, although slight shifts in Tm peaks were observed. Inter- and intra-assay reproducibility was evaluated using 6 panels of commercial standards, producing variation coefficients of 5% and 2%, respectively. Assay accuracy results reflected a good correlation with a mean difference of 0.10 log10 copies/mL. The results of the prospective study showed 6/102 (5.8%) patients had HAdV viremia, including 4 (3.9%) patients with a viral load ≥4 log10/mL, which might necessitate therapy.ConclusionThe HAdV quantitative assay using the Luminex ARIES® system provides excellent performance for routine testing with the additional advantage of random access capabilities for urgent testing to identify patients at risk for disseminated disease.Disclosures All authors: No reported disclosures.

Unimodal Model-Based Inter Mode Decision for High Efficiency Video Coding

In this paper, a fast inter mode decision algorithm, called the unimodal model-based inter mode decision (UMIMD), is proposed for the latest video coding standard, the high-efficiency video coding. Through extensive simulations, it has been observed that a unimodal model (i.e., with only one global minimum value) can be established among the size of different prediction unit (PU) modes and their resulted rate-distortion (RD) costs for each quad-tree partitioned coding tree unit (CTU). To guarantee the unimodality and further search the optimal operating point over this function for each CTU, all the PU modes need to be first classified into 11 mode classes according to their sizes. These classes are then properly ordered and sequentially checked according to the class index, from small to large so that the optimal mode can be early identified by checking when the RD cost starts to arise. In addition, an effective instant SKIP mode termination scheme is developed by simply checking the SKIP mode against a pre-determined threshold to further reduce the computational complexity. The extensive simulation results have shown that the proposed UMIMD algorithm is able to individually achieve a significant reduction on computational complexity at the encoder by 61.9% and 64.2% on average while incurring only 1.7% and 2.1% increment on the total Bjontegaard delta bit rate (BDBR) for the low delay and random access test conditions, compared with the exhaustive mode decision in the HEVC. Moreover, the experimental results have further demonstrated that the proposed UMIMD algorithm outperforms multiple state-of-the-art methods.

Low complexity Bi-Partition mode selection for 3D video depth intra coding

This paper proposes a fast mode decision algorithm for 3D High Efficiency Video Coding (3D-HEVC) depth intra coding. In the current 3D-HEVC design, it is observed that for most of the cases, full rate-distortion (RD) cost search of Bi-Partition mode could be skipped since most coding units (CUs) of depth map are very flat or smooth while Bi-Partition modes are designed for CUs with edge or sharp transition. Using the rough RD cost value calculated by HEVC Rough Mode Decision as a selection threshold, we propose a fast Bi-Partition modes selection algorithm to speed up the encoding process. The test result for the proposed fast algorithm reports a 34.4% encoding time saving with a 0.3% bitrate increase on synthesized views for the All-Intra test case and negligible impact under the random access test case. Moreover, by simply varying the selection threshold, we can make a tradeoff between encoding time saving and bitrate loss based on the requirement of different applications.

Rapid measurement of tacrolimus in whole blood by paper spray-tandem mass spectrometry (PS-MS/MS)

BackgroundLiquid chromatography-tandem mass spectrometry (LC-MS/MS) provides sensitivity and specificity for monitoring tacrolimus drug level in blood, but it requires an LC system and sample preparation, which is not amenable to random access testing typical of immunoassays. Paper spray (PS) ionization generates gas phase analyte ions directly from dried blood spots without sample preparation and LC. We evaluated a PS-MS/MS method for tacrolimus drug monitoring in a clinical diagnostic laboratory. MethodsWhole blood sample was mixed with stable isotope labeled internal standard ([13C, 2H2]-FK506) and spotted onto a cartridge containing triangular shaped card paper. After drying, samples were analyzed by PS MS/MS in the selected reaction monitoring (SRM) mode, with a run time of 3min/sample. ResultsAnalytical measurement range was 1.5–30ng/ml. Assay inter-day imprecision was 13%, 8%, and 5% at tacrolimus concentrations of 4.5, 10.5, and 24.5ng/ml, respectively. Accuracy was determined by pure tacrolimus solution and was confirmed by result correlation to an immunoassay (slope=1.0, intercept=−0.02; r2=0.99), and to a conventional LC-MS/MS method (slope=0.90, intercept=0.4; r2=0.94). ConclusionsPS-MS/MS provides accurate results for tacrolimus with rapid turnaround time amenable to random access testing protocols.

Control-Point Representation and Differential Coding Affine-Motion Compensation

The affine-motion model is able to capture rotation, zooming, and the deformation of moving objects, thereby providing a better motion-compensated prediction. However, it is not widely used due to difficulty in both estimation and efficient coding of its motion parameters. To alleviate this problem, a new control-point representation that favors differential coding is proposed for efficient compression of affine parameters. By exploiting the spatial correlation between adjacent coding blocks, motion vectors at control points can be predicted and thus efficiently coded, leading to overall improved performance. To evaluate the proposed method, four new affine prediction modes are designed and embedded into the high-efficiency video coding test model HM1.0. The encoder adaptively chooses whether to use the new affine mode in an operational rate-distortion optimization. Bitrate savings up to 33.82% in low-delay and 23.90% in random-access test conditions are obtained for low-complexity encoder settings. For high-efficiency settings, bitrate savings up to 14.26% and 4.89% for these two modes are observed.