Objective: To evaluate telemedicine (TM) use during the COVID-19 pandemic among people with neurological disorders (pwND), including multiple sclerosis (MS), Alzheimer9s disease (AD) and Parkinson's disease (PD). Background: Use of TM increased during the pandemic; however, it is unclear how its use and accessibility varies among pwND. Design/Methods: This cross-sectional study used US PharMetrics Plus commercial claims data from January 1, 2019–December 31, 2021. TM use, identified using ≥1 current procedural terminology codes, was assessed in each study year (2019, 2020, 2021) among people with ≥1 inpatient or ≥2 outpatient diagnosis codes ≥30 days apart for MS, AD or PD. Any TM use and ND-related visits (MS, AD, PD diagnosis code within TM claim) were summarized, and characteristics of TM users vs nonusers during the pandemic (2020 and 2021) were described. Results: Among pwND, 0.9% (933/101,598 pwND) used TM in 2019 compared with 58.0% (55,517/95,715 pwND) in 2020 and 42.5% (46,315/109,029 pwND) in 2021. Among TM users in 2020 and 2021, the majority had ND-related TM visits (73.2% and 64.6%, respectively); the mean (SD) number of claims was 2.9 (2.8) in 2020 and 2.7 (3.0) in 2021. During the pandemic, nearly 26% of total TM visits (n=296,434) were provided by a neurologist. Mean (SD) age of TM users was similar to nonusers (60.5 [15.1] and 61.5 [15.3] years), but TM users were more likely to be female (62% vs 60%), enrolled in Medicare (33% vs 30%) and reside in western and eastern regions compared with nonusers. The proportion of pwND using TM was highest in Massachusetts (81.3%), Vermont (77.1%) and California (72.4%). Conclusions: About half of pwND in a commercially insured population used TM during the pandemic; its use varied most notably by region and state. Additional analyses will inform gaps in TM access and its long-term utility. Disclosure: Dr. Patel has received personal compensation for serving as an employee of Genentech. An immediate family member of Dr. Patel has received personal compensation for serving as an employee of Google. Dr. Patel has stock in Genentech Inc.. An immediate family member of Dr. Patel has stock in Google. Dr. Schuldt has received personal compensation for serving as an employee of Genentech. Dr. Schuldt has stock in Genentech. Dr. Boudreau has received personal compensation for serving as an employee of Genentech, Inc.. Dr. Boudreau has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Syneos Health. The institution of Dr. Boudreau has received research support from NIH and FDA. Dr. Boudreau has received personal compensation in the range of $5,000-$9,999 for serving as a Committee member with FDA. Nikki Win has received personal compensation for serving as an employee of Genentech. Nikki Win has stock in Genentech . Dr. Cobb has received personal compensation for serving as an employee of Genentech. Dr. Cobb has stock in Roche. Dr. Cobb has received intellectual property interests from a discovery or technology relating to health care. Dr. McGinley has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Octave. Dr. McGinley has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. McGinley has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for EMD Serono. The institution of Dr. McGinley has received research support from Novartis. The institution of Dr. McGinley has received research support from Biogen. The institution of Dr. McGinley has received research support from Genentech. The institution of Dr. McGinley has received research support from NIH.

Objective: To assess the utility of plasma neurofilament light chain (pNfL) as a biomarker of neurodegenerative diseases using a fixed threshold for screening in clinical practice. Background: Elevated pNfL is a marker of neuroaxonal injury in neurodegenerative diseases. However, no threshold has been established for clinically meaningful pNfL elevations for use as a routine screening tool in primary care settings. Design/Methods: For this post hoc analysis, baseline pNfL levels were analyzed from Phase III studies of patients with Stage I or II Huntington's disease (HD; NCT03664804; n=89), prodromal to mild Alzheimer's disease (AD; NCT03114657; n=1124), early Parkinson's disease (PD; NCT03100149; n=270) and a cohort of healthy controls (HC; n=690) using the Elecsys platform, and among patients with primary progressive multiple sclerosis (PPMS; NCT01194570; n=498) and an HC cohort (n=117) using the Quanterix pNfL Advantage kit. Median ± IQR unadjusted pNfL levels were calculated, and differences from median HC levels were determined for disease cohorts. Results: In patients with HD, pNfL levels were elevated 12.9-fold over the HC median level. pNfL levels were elevated to a lesser extent in patients with AD (1.5-fold) and were slightly lower than HCs among patients with early PD (0.9-fold). Among patients with PPMS, pNfL levels were elevated 1.8-fold over the HC median. For all disease cohorts except HD, pNfL IQRs overlapped with those of HCs. Conclusions: Elevated pNfL levels vs HCs were observed among HD, AD, and PPMS cohorts but not in early PD, consistent with previous reports. However, no clinically meaningful threshold using a fixed cutoff for pNfL elevation across neurodegenerative diseases could be established. The findings from this study, the first to evaluate pNfL levels from clinical trials across multiple neurological diseases, support further investigation of the clinical utility of pNfL as a neurological screen in primary care. Disclosure: Dr. Cameron has received personal compensation for serving as an employee of Genentech. Dr. Cameron has stock in Genentech. Dr. Patel has received personal compensation for serving as an employee of Genentech. An immediate family member of Dr. Patel has received personal compensation for serving as an employee of Google. Dr. Patel has stock in Genentech Inc.. An immediate family member of Dr. Patel has stock in Google. Dr. Cobb has received personal compensation for serving as an employee of Genentech. Dr. Cobb has stock in Roche. Dr. Cobb has received intellectual property interests from a discovery or technology relating to health care. Ivonne Suridjan has nothing to disclose. Nikki Win has received personal compensation for serving as an employee of Genentech. Nikki Win has stock in Genentech .

Introduction: Molecular diagnostics is a key component of laboratory medicine. Here, the authors review key triggers of ever-increasing automation in nucleic acid amplification testing (NAAT) with a focus on specific automated Polymerase Chain Reaction (PCR) testing and platforms such as the recently launched cobas (R) 6800 and cobas (R) 8800 Systems. The benefits of such automation for different stakeholders including patients, clinicians, laboratory personnel, hospital administrators, payers, and manufacturers are described.Areas Covered: The authors describe how molecular diagnostics has achieved total laboratory automation over time, rivaling clinical chemistry to significantly improve testing efficiency. Finally, the authors discuss how advances in automation decrease the development time for new tests enabling clinicians to more readily provide test results.Expert Commentary: The advancements described enable complete diagnostic solutions whereby specific test results can be combined with relevant patient data sets to allow healthcare providers to deliver comprehensive clinical recommendations in multiple fields ranging from infectious disease to outbreak management and blood safety solutions.

Chronic hepatitis B, C, and D virus infections contribute significantly to the morbidity and mortality of immunocompromised individuals. To contextualize discussion of these infections in immunocompromised patients, this paper provides an overview of aspects of infection in normal hosts. It then describes differences in disease, diagnostic testing, and therapeutic management observed in immunocompromised patients.

BACKGROUND:The COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v2.0 (CAP/CTM2) is used for HCV RNA viral load monitoring.OBJECTIVES:The performance of the CAP/CTM2 was compared to other widely used tests, including a manual version of the assay (the COBAS(®) TaqMan(®) HCV Test, v2.0 for use with the High Pure System, HPS/CTM2) predominantly used during phase III clinical trials for the new direct acting antiviral therapies.STUDY DESIGN:Low HCV RNA level comparisons were performed across tests (Abbott Realtime HCV Test, ART; COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v1.0, CAP/CTM1; CAP/CTM2; and HPS/CTM2) using dilutions of the 2nd HCV WHO International Standard. Additionally, the clinical performance of the CAP/CTM2 was evaluated with 421 leftover HCV RNA-positive routine clinical samples.RESULTS:All quantifiable WHO dilutions were within ±0.3log10IU/mL of the expected results across tests and the analytical sensitivity resulted in a limit of detection of 12IU/mL (95% confidence interval, 10, 15). When clinical samples were tested the results for 87% (367 of 421) of all sample comparisons were within ±0.5log10IU/mL. When low viral load results (25-3500IU/mL) were compared, values obtained by the ART assay were significantly lower (p<0.0001) than those obtained with the CAP/CTM2.CONCLUSIONS:The new CAP/CTM2 showed good accuracy with comparable sensitivity to comparator assays. The new kit is well-suited for use in the routine diagnostic laboratory, especially for accurate monitoring of patients receiving triple therapy or interferone-free regimens.

ABSTRACT Discrepancies between HIV-1 RNA results assayed by different FDA-approved platforms have been reported. Plasma samples collected from 332 randomly selected clinical trial participants during the second year of antiretroviral treatment were assayed with three FDA-approved platforms: UltraSensitive Roche Amplicor Monitor, v1.5 (Monitor), the Abbott RealTime HIV-1 test on the m2000 system (Abbott), and the Roche TaqMan HIV-1 test, v2.0 (TaqMan). Samples from 61 additional participants with confirmed HIV-1 RNA levels of >50 copies/ml during trial follow-up were also included. Endpoints were HIV-1 RNA quantification of ≤50 copies/ml versus >50 copies/ml at an individual-sample level (primary) and determination of confirmed virologic failure (VF) from longitudinal samples. A total of 389 participants had results obtained from all assays on at least one sample (median = 6). Proportions of results of >50 copies/ml were 19% (Monitor), 22% (TaqMan), and 25% (Abbott). Despite indication of strong agreement (Cohen's kappa, 0.76 to 0.82), Abbott was more likely to detect HIV-1 RNA levels of >50 copies/ml than Monitor (matched-pair odds ratio [mOR] = 4.2; modified Obuchowski P < 0.001) and TaqMan (mOR = 2.1; P < 0.001); TaqMan was more likely than Monitor (mOR = 2.6; P < 0.001). Despite strong agreement in classifying VF across assay comparisons (kappa, 0.75 to 0.92), at a 50-copies/ml threshold, differences in the probability of VF classification (in the same direction as primary) were apparent (all McNemar's P < 0.007). At a 200-copies/ml VF threshold, no differences between assays were apparent (all P > 0.13). Despite strong agreement among assays, significant differences were observed with respect to detecting HIV-1 RNA levels of >50 copies/ml and identifying VF at the 50-copies/ml threshold. This has important implications for the definition of VF in clinical trials and clinical practice.

Molecular tests that detect and/or quantify HCV RNA are important in the diagnosis and management of patients with chronic hepatitis C (CHC) undergoing anti-viral therapy. The primary goal of anti-HCV therapy is to achieve a sustained virologic response (SVR) defined as "undetectable" Hepatitis C Virus (HCV) RNA in the serum or plasma at 12 to 24 weeks following the end of treatment.

Cytomegalovirus (CMV) replication in organ transplant recipients is commonly diagnosed by quantitative PCR methods. However, there has been a poor inter-laboratory correlation of viral load values due to the lack of an international reference standard. In a recent study, the COBAS® AmpliPrep/COBAS® TaqMan® (CAP/CTM) CMV test calibrated to the 1st WHO CMV standard, showed good reproducibility in CMV load values across multiple laboratories. Fifty-seven follow-up plasma specimens from 10 kidney transplant recipients with CMV replication were examined using the new quantitative CAP/CTM CMV test and the "in-house" quantitative CMV real-time PCR method, also calibrated against the 1st WHO CMV standard for their clinical applicability for monitoring CMV load in renal transplant patients. By CAP/CTM CMV test 49/57 specimens were CMV-DNA positive compared to 44/57 by the "in-house" PCR test. The "in-house" PCR and CAP/CTM CMV test correlated well in monitoring individual kidney transplant patients. Conversion of the CMV-DNA copies to IUs made the results of the "in-house" PCR and CAP/CTM CMV test less uniform in analysis of the patient samples. In specimens of one patient, significant underquantification of CMV load with "in-house" PCR emerged during follow-up due to a point mutation in the "in-house" PCR primer sequence. The CAP/CTM CMV test was found suitable for diagnosing and monitoring CMV replication in renal transplant patients. Multicenter studies are needed to provide more information of the commutability of the 1st WHO CMV standard and to define the clinical thresholds.

Recent regulatory approvals of the NS3/4A protease inhibitors boceprevir and telaprevir launched a new therapeutic era for hepatitis C virus (HCV) genotype 1 infection. Decisions to shorten, extend, or stop treatment with these direct-acting antiviral (DAA) regimens require accurate quantification of serum HCV RNA levels. To effectively use DAA therapies, clinicians must understand performance characteristics of HCV RNA real-time PCR assays and the clinical significance of HCV RNA that is detectable below the lower limit of quantification. This review summarizes terms used to report HCV RNA viral load results, explains the analytical performance of the PCR assay used in the clinical trials of boceprevir and telaprevir, and compares currently available commercial assays.

Low-level viremia during antiretroviral therapy and its accurate measurement are increasingly relevant. Here, we present an international collaboration of 4,221 paired blood plasma viral load (pVL) results from four commercial assays, emphasizing the data with low pVL. The assays compared were the Abbott RealTime assay, the Roche Amplicor assay, and the Roche TaqMan version 1 and version 2 assays. The correlation between the assays was 0.90 to 0.97. However, at a low pVL, the correlation fell to 0.45 to 0.85. The observed interassay concordance was higher when detectability was defined as 200 copies/ml than when it was defined as 50 copies/ml. A pVL of ∼100 to 125 copies/ml by the TaqMan version 1 and version 2 assays corresponded best to a 50-copies/ml threshold with the Amplicor assay. Correlation and concordance between the viral load assays were lower at a low pVL. Clear guidelines are needed on the clinical significance of low-level viremia.

ABSTRACT Hepatitis C virus (HCV) RNA viral load (VL) monitoring is a well-established diagnostic tool for the management of chronic hepatitis C patients. HCV RNA VL results are used to make treatment decisions with the goal of therapy to achieve an undetectable VL result. Therefore, a sensitive assay with high specificity in detecting and accurately quantifying HCV RNA across genotypes is critical. Additionally, a lower sample volume requirement is desirable for the laboratory and the patient. This study evaluated the performance characteristics of a second-generation real-time PCR assay, the Cobas AmpliPrep/Cobas TaqMan HCV quantitative test, version 2.0 (CAP/CTM HCV test, v2.0), designed with a novel dual-probe approach and an optimized automated extraction and amplification procedure. The new assay demonstrated a limit of detection and lower limit of quantification of 15 IU/ml across all HCV genotypes and was linear from 15 to 100,000,000 IU/ml with high accuracy (<0.2-log 10 difference) and precision (standard deviation of 0.04 to 0.22 log 10 ). A specificity of 100% was demonstrated with 600 HCV-seronegative specimens without cross-reactivity or interference. Correlation to the Cobas AmpliPrep/Cobas TaqMan HCV test (version 1) was good ( n = 412 genotype 1 to 6 samples, R 2 = 0.88; R 2 = 0.94 without 105 genotype 4 samples). Paired plasma and serum samples showed similar performance ( n = 25, R 2 = 0.99). The sample input volume was reduced from 1 to 0.65 ml in the second version. The CAP/CTM HCV test, v2.0, demonstrated excellent performance and sensitivity across all HCV genotypes with a smaller sample volume. The new HCV RNA VL assay has performance characteristics that make it suitable for use with currently available direct-acting antiviral agents.

Background. Quantification of cytomegalovirus (CMV) load is central to the management of CMV infections in immunocompromised patients, but quantitative results currently differ significantly across methods and laboratories.Methods. The COBAS AmpliPrep/COBAS TaqMan CMV Test (CAP/CTM CMV test), developed using the first World Health Organization CMV standard in the calibration process, was compared to local assays used by 5 laboratories at transplant centers in the United States and Europe. Blinded plasma panels (n = 90) spiked with 2.18-6.7 log(10) copies/mL and clinical plasma samples from immunocompromised patients (n = 660) were tested.Results. Observed mean panel member concentrations by site and 95% confidence intervals (CIs) of the data combined across sites were narrower for CAP/CTM CMV test compared with local assays. The 95% CI in log(10) copies/mL of the combined data per panel member for CAP/CTM CMV test vs comparator assays was .17 vs 1.5 at 2.18 log(10) copies/mL; .14 vs .52 at 2.74 log(10) copies/mL; .16 vs .6 at 3.3 log(10) copies/mL; .2 vs 1.11 at 4.3 log(10) copies/mL; .21 vs 1.13 at 4.7 log(10) copies/mL; and .18 vs 1.4 at 6.7 log(10) copies/mL. In clinical specimens, constant and variable quantification differences between the CAP/CTM CMV test and comparator assays were observed.Conclusions. High interlaboratory agreement and precision of CAP/CTM CMV test results across 5 different laboratories over 4 orders of magnitude suggest that this assay could be valuable in prospective studies identifying clinical viral load thresholds for CMV treatment.

Background: Sensitive and reliable diagnostic tests are essential for the prevention of cytomegalovirus (CMV) disease after hematopoietic stem cell transplantation (HSCT). pp65 antigenemia and polymerase chain reaction (PCR) assays are commonly used to monitor CMV in HSCT recipients. However, there is considerable intra-and inter-laboratory variability in the results, which impact comparability and clinical practice.Objectives/study design: Using 380 samples from 135 HSCT recipients, we compared the new FDA approved quantitative PCR assay, COBAS (R) AmpliPrep/COBAS (R) TaqMan (R) CMV test (CAP/CTM CMV test) developed and standardized using the 1st WHO International Standard for CMV with pp65 antigenemia and COBAS (R) AMPLICOR MONITOR CMV tests.Results: The median time between transplantation and testing samples was 57 days (range, 0-207 days). The median CMV load (log(10)) was 3.17 IU/mL (3.21 copies/mL). Among samples with detectable CMV load, 52% were negative by pp65 antigenemia. CMV loads were higher in pp65 antigenemia-positive than in negative samples. One pp65-antigenemia-positive cell per 100,000 leukocytes corresponded to a median CMV load of 1200 IU/mL. CMV loads determined by the CAP/CTM CMV test were slightly lower than the ones by the AMPLICOR MONITOR CMV test (-0.15 [95% CI, -0.18 to -0.13] copies/mL), but slope differences indicated only limited co-linearity.Conclusions: The CAP/CTM CMV test is more sensitive than pp65 antigenemia and the AMPLICOR MONITOR CMV test in HSCT recipients. The lower limit of quantification and co-linearity with the international WHO standard renders the CAP/CTM CMV test suitable for future clinical trials defining viral load thresholds of CMV therapy. (C) 2012 Elsevier B. V. All rights reserved.

Two FDA-approved (in vitro diagnostic [IVD]) hepatitis B virus (HBV) viral load assays, the manual Cobas TaqMan HBV Test for use with the High Pure System (HP) and the automated Cobas AmpliPrep/Cobas TaqMan HBV Test v2.0 (CAP/CTM), were compared to a modified (not FDA-approved) version of the HP assay by automating the DNA extraction using the Total Nucleic Acid Isolation (TNAI) kit on the Cobas AmpliPrep. On average, CAP/CTM measurements were 0.08 log IU/ml higher than HP results (n = 206), and TNAI results were 0.17 log IU/ml higher than HP results (n = 166). The limit of detection (LOD), as determined by probit analysis using dilutions of the 2nd HBV international standard, was 10.2 IU/ml for CAP/CTM. The data sets for HP and TNAI were insufficient for probit analysis; however, there was 100% detection at ≥ 5 or ≥ 10 IU/ml for TNAI and HP, respectively. Linearity was demonstrated between 60 and 2,000,000 IU/ml, with slopes between 0.95 and 0.99 and R(2) values of >0.99 for all assays. Total precision (log percent coefficient of variance [CV]) was between 0.8% and 2.1% at 4.3 log IU/ml and between 1.4% and 4.9% at 2.3 log IU/ml. Correlation of samples, reproducibility, linearity, and LOD were acceptable and similar in all assays. The CAP/CTM assay and, to a lesser extent, the TNAI assay reduced hands-on time due to automation. There were no instances of contamination detected in negative samples during the course of the study, despite testing several samples up to 9.6 log IU/ml. The incidence of false-positive negative controls in HP and CAP/CTM clinical testing was <0.5% over 6 to 7 months of testing.