Ortho Clinical Diagnostics Research Articles

Triiodothyroacetic Acid Cross-Reacts With Measurement of Triiodothyronine (T3) on Various Immunoassay Platforms.

Thyroid hormone analog 3,5,3'-triiodothyroacetic acid (TRIAC) is effective in reducing the hypermetabolism in monocarboxylate transporter 8 (MCT8)-deficient individuals. Because of the structural similarity between TRIAC and 3,3',5'-triiodothyronine (T3), we sought to investigate the degree of cross-reactivity of TRIAC with various commercially available total and free T3 assays. Varying concentrations (50-1,000 ng/dL) of TRIAC (Sigma Aldrich) were added to pooled serum and assayed for total T3 (TT3) and free T3 (FT3) on the following platforms: e602 (Roche Diagnostics), Architect (Abbott Diagnostics), Centaur (Siemens Healthcare Diagnostics), IMMULITE (Siemens Healthcare Diagnostics), DxI (Beckman Coulter), and Vitros (Ortho Clinical Diagnostics). TT3 competition assay with TRIAC was performed by adding increasing amounts of T3 to pooled serum samples that contained a constant concentration of TRIAC (250 ng/dL). Significant overestimation of TT3 and FT3 assays were observed across all platforms corresponding to increasing concentrations of TRIAC. The TRIAC effect at 250 ng/dL showed a constant interference of approximately 190 ng/dL TT3. All commercial TT3 and FT3 assays tested in this work cross-react significantly with TRIAC. Therefore, patients undergoing TRIAC therapy should have T3 hormone response monitored using alternative nonimmunoassay-based methods to avoid misinterpretation of thyroid function profiles.

Centralization of multisite reagent lot-to-lot validation for Ortho Clinical Vitros chemistry instruments

ObjectiveReagent lot-to-lot comparisons are recommended by accreditation bodies to ensure that the performance of each reagent lot meets acceptable standards for quality patient results. The general approach is comprised of performing quality control (QC) and patient comparison between the old and new reagent lots and evaluating against a pre-defined criteria. Reagent lot comparison practices are often variable despite using the same instrument across different laboratories. This is costly, time consuming, and can lead to variability in acceptance criteria. While Clinical & Laboratory Standards Institute (CLSI) has a recommended guideline for reagent lot validation, it is often difficult to execute for small and rural laboratories due to limited resources. Defining the analytes required for detailed validation is important to allocate appropriate resources to ensure quality patient results. The goal of this study was to develop a standardized approach to reagent lot validation and optimize lab resources on Vitros chemistry instruments. Design and MethodThis study consists of a retrospective and prospective analysis of reagent lot changes in dry slide chemistry analyzers (Ortho Clinical Diagnostics Vitros). Two years of retrospective reagent lot comparison data was obtained at a single site. A prospective study was conducted by assessing aliquots of 10 patient sample pools at 9 sites with Vitros analyzers. ResultsOf the 19 chemistry analytes evaluated, albumin, sodium, and total protein showed significant differences between reagent lots and also exceeded the pre-defined acceptance criteria. ConclusionFor these analytes, our recommendations are to perform a comprehensive lot validation with QC and patient samples. A simple lot validation with a reflex approach comprised of initially assaying QC can be adapted for the more stable analytes to allow achieving quality patient result in a resource constraint rural environment.

Comparison between tube test and automated column agglutination technology on VISION Max for anti-A/B isoagglutinin titres: A multidimensional analysis.

VISION Max (Ortho Clinical Diagnostics, Raritan, NJ) measures anti-A/B isoagglutinin titres using automated column agglutination technology (CAT). We compared tube test (TT) and CAT of VISION Max comprehensively, including failure mode and effect analysis (FMEA), turnaround time (TAT) and cost, and suggested modified CAT (MCAT). For 100 samples (each 25 for blood type A, B and O with anti-A and anti-B), anti-A/B isoagglutinin titres were measured by TT and CAT (1:2-1:1024 dilution), as well as by MCAT (with agglutination at 1:32 dilution, then perform additional testing from 1:64 to 1:1024). We assessed the agreement and correlation between TT and CAT and compared FMEA (risk priority number [RPN] score), TAT (h:min:sec) and cost (US dollar, US $) among TT, CAT and MCAT. TT and CAT showed overall substantial agreement (k=0.73) and high correlation (ρ ≥ 0.75) except blood type O with anti-A (ρ=0.68). Compared with TT, CAT showed lower RPN scores in FMEA and similar TAT and cost (FMEA, 33,700 vs. 184,300; TAT, 15:23:00 vs. 14:26:40; cost, 1377.4 vs. 1312.4, respectively). Regarding FMEA, TAT and cost, MCAT was superior to CAT or TT (43,810; 13:28:00; 899.2, respectively). This is the first multidimensional analysis on VISION Max CAT for measuring anti-A/B isoagglutinin titres. The results of anti-A/B isoagglutinin titres by CAT were comparable with those of TT. MCAT would be a safe, time-saving and cost-effective alternative to TT and CAT in high-volume blood bank laboratories.

Analytical platforms Vitros ECi 3600 and Cobas 6000: comparative analysis of prolactin measurement.

Prolactin is a polypeptide hormone secreted by the lactotrophic cells of the anterior pituitary gland and has a wide range of biological effects in the human body. Accurate measurements of prolactin concentration are essential in obtaining biochemical data to support clinical decisions in the diagnosis, treatment and prevention of diseases of the pituitary gland, reproductive, immune and other body systems. The aim of our study is to carry out a comparative analysis of the serum prolactin measurement determined by the two analytical platforms Vitros ECi 3600 (Ortho-Clinical Diagnostics) and Cobas 6000 (Roche). Serum samples from 664 patients undergoing examination at the Endocrinology Research Center were included in the study. Comparative analysis of serum prolactin measurement showed that results obtained by the two analytical systems are consistent with each other (r = 0.89, p<0,05). Clinically accuracy of prolactin measurement and to a large extent using the same method is of particular importance in primary diagnosis, treatment and long-term follow-up of the patient.

Performance Evaluation: Four Chemiluminescent SARS-Cov-2 Immunoassays and Rapid-Card Test in Mild Disease and Seroprevalence of SARS CoV-2 in Frontline Healthcare Workers

Introduction: The COVID-19 pandemic raised a host of challenges to modern medicine. Key amongst these were in diagnostics, as most SARS-CoV-2 assays had been rapidly developed and released under emergency-use authorization with limited validation on clinical samples and secondly, an increased risk of COVID-19 infection to healthcare workers (HCW). There are limited inter-assay comparisons to detect SARS-CoV-2 antibodies in cases with milder symptoms of COVID-19, necessary to evaluate whether assays can detect SARS-CoV-2 antibodies in patients with mild infection. &#x0D; Aim: Therefore this study aimed to evaluate the performance of four chemiluminescence immunoassays and a rapid immunochromatographic assay in 100 rRT-PCR diagnosed-recovered frontline HCW with milder COVID-19 disease and secondly to evaluate the seroprevalence of SARS-CoV-2 infection in the asymptomatic frontline HCW at a multispeciality hospital in Delhi, India. Study Design: Serum and plasma samples were obtained from 100 rRT-PCR diagnosed-recovered frontline HCWs with mild disease working across the hospital, and performance of four common chemiluminescence immunoassays evaluated. Also samples of 505 asymptomatic, frontline HCWs working in hospital, who had not developed or shown any symptoms of COVID-19 infection to date was collected and the seroprevalence of infection was evaluated.&#x0D; Place and Duration of the Study: A study was conducted at BLK Superspeciality Hospital, New Delhi from September to October 2020.&#x0D; Methods: Four chemiluminescence immunoassays [Abbott SARS-CoV-2 IgG (Nucleocapsid), Roche Elecsys® Anti-SARS-CoV-2 Total (Nucleocapsid), Ortho-Clinical Diagnostics: VITROS Anti-SARS-CoV-2 IgG (Spike) and Anti-SARS-CoV-2 Total (Spike)] and a rapid assay [Medsource Ozone Biomedicals] were evaluated in 100 rRT-PCR diagnosed-recovered frontline HCW with mild disease. Also, seroprevalence was studied in 505 asymptomatic, frontline HCW. &#x0D; Results: At manufacturers' thresholds, overall sensitivity for Abbott was 71%, Roche 96%, Ortho (both total and IgG(S) 99% and rapid card 56%. Seroprevalence in asymptomatic frontline HCW was found to be 17.6%, with positivity being higher in the HCW group not facing patients directly compared to direct patient caregivers (P = 0.0034).&#x0D; Conclusion: Assay performance depends on assay design (total IgM &amp; IgG antibodies versus IgG alone), choice of antigen, and time of sample testing from the onset of disease. In our study, Ortho Vitros total-Ab; IgG (Spike), and Roche Elecsys total-Ab (Nucleocapsid) assays were found to have optimal sensitivity. A seroprevalence study in the frontline HCWs at our institute showed that seroprevalence was higher (17.6%) in HCWs in comparison to the community.

Assessment of automated high-throughput serological assays for prediction of high-titer SARS-CoV-2 neutralizing antibody

COVID19 convalescent patient plasma units with high titer neutralizing antibody can be used to treat patients with severe disease. Therefore, in order to select suitable donors, neutralizing antibody titer against SARS CoV-2 needs to be determined. Because the neutralization assay is highly demanding from several points of view, a pre-selection of sera would be desirable to minimize the number of sera to be tested. In this study, a total of 140 serum samples that had been titrated for SARS-CoV-2 neutralizing antibody by microneutralization assay were also tested for the presence of anti-SARS-CoV2 antibody using 5 different tests: Architect® immunoassay (Abbott Diagnostics), detecting IgG against the nucleocapsid protein, LIAISON XL® (Diasorin) detecting IgG against a recombinant form of the S1/S2 subunits of the spike protein, VITROS® (Ortho Clinical Diagnostics), detecting IgG against a recombinant form of the spike protein, and ELISA (Euroimmun AG), detecting IgA or IgG against a recombinant form of the S1 subunit. To determine which immunoassay had the highest chance to detect sera with neutralizing antibodies above a certain threshold, we compared the results obtained from the five immunoassays with the titers obtained by microneutralization assay by linear regression analysis and by using receiver operating characteristic curve and Youden's index. Our results indicate that the most suitable method to predict sera with high Nab titer is Euroimmun® IgG, followed closely by Ortho VITROS® Anti-SARS-CoV-2 IgG.

Analytical assessment and performance of the 0/3h algorithm with novel high sensitivity cardiac troponin I

BackgroundRecently, Ortho Clinical Diagnostics have launched a high sensitivity cardiac troponin I assay adapted on Vitros3600 / 5600. We aimed at evaluating the analytical and clinical performances using the 0/3-hour algorithm, of the Ortho hs-cTnI assay on the Vitros 3600® (Ortho Clinical Diagnostics, Illkirch, France) analyzer with comparison to Roche hs-cTnT assay on the Cobas8000/e801® module (Roche diagnostics, Meylan, France) and the Abbott STAT hs-cTnI assay on the Alinity i® (Abbott, Rungis, France) analyzer. MethodsImprecision studies, linearity, limit of detection, and the interference to hemolysis were performed for Ortho hs-cTnI assay. The concordance study was based on results of troponin obtained from 160 patients with chest pain to the emergency department. Testing was performed simultaneously measuring the Roche hs-cTnT and the Ortho hs-cTnI, then on remaining sample the concentration of Abbott hs-cTnI (n = 150). We applied the 0/3h algorithm to rule out/rule in, in acute myocardial infarction. ResultsAnalytical performances were acceptable and in accordance with manufacturer’s data. For late presenters 100, 92.8 and 88.8% patients could be rule-out with Roche, Ortho and Abbott assay, respectively with one NSTEMI missed with both hs-TnI assays. Applying the hs-cTn cut-offs from 0/3-hour algorithm, 107 (66.8%) could be rule out with Roche hs-cTnT with no AMI missed (sensitivity 100% [95%CI: 90.5 to 100] and NPV 100%); 89 with Ortho hs-cTnI (sensitivity 97.3% [95%CI: 85.8–99.9] and NPV 98.8% [95%CI:92.7–99.8]); and 61 with Abbott hs-cTnI (sensitivity 97% [95%CI: 84.2–99.9] and NPV 98.4% [95%CI: 89.8–99.7]). For rule-in, 23.7% (n = 37) from the total population would be designated in this group, with a specificity of 86.9% (95%CI: 79.7–92.4) and PPV of 69.8% (95%CI: 59.4–78.5) vs specificity of 72.3% (95%CI:63.5–80.0) and PPV of 51.4% (95%CI: 44.1–58.2)with Roche hs-cTnT vs Ortho hs-cTnI respectively; and with Abbott, 33 patients had constitued this group with a specificity of 52.1% (95%CI:42.7–61.4) and PPV of 36.4% (95%CI: 32.0–41.0). ConclusionIn conclusion, according to ESC guidelines, our results indicate that the Ortho hs-cTnI assay for the Vitros 3600 instrument is a method that may be used in the clinical practice using 0/3-hour algorithm.

Distinct SARS-CoV-2 antibody reactivity patterns in coronavirus convalescent plasma revealed by a coronavirus antigen microarray

A coronavirus antigen microarray (COVAM) was constructed containing 11 SARS-CoV-2, 5 SARS-1, 5 MERS, and 12 seasonal coronavirus recombinant proteins. The array is designed to measure immunoglobulin isotype and subtype levels in serum or plasma samples against each of the individual antigens printed on the array. We probed the COVAM with COVID-19 convalescent plasma (CCP) collected from 99 donors who recovered from a PCR+ confirmed SARS-CoV-2 infection. The results were analyzed using two computational approaches, a generalized linear model (glm) and random forest (RF) prediction model, to classify individual specimens as either Reactive or non-reactive against the SARS-CoV-2 antigens. A training set of 88 pre-COVID-19 specimens (PreCoV) collected in August 2019 and102 positive specimens from SARS-CoV-2 PCR+ confirmed COVID-19 cases was used for these analyses. Results compared with an FDA emergency use authorized (EUA) SARS-CoV2 S1-based total Ig chemiluminescence immunoassay (Ortho Clinical Diagnostics VITROS Anti-SARS-CoV-2 Total, CoV2T) and with a SARS-CoV-2 S1-S2 spike-based pseudovirus micro neutralization assay (SARS-CoV-2 reporter viral particle neutralization titration (RVPNT) showed high concordance between the three assays. Three CCP specimens that were negative by the VITROS CoV2T immunoassay were also negative by both COVAM and the RVPNT assay. Concordance between VITROS CoV2T and COVAM was 96%, VITROS CoV2T and RVPNT 93%, and RVPNT and COVAM 91%. The discordances were all weakly reactive samples near the cutoff threshold of the VITROS CoV2T immunoassay. The multiplex COVAM allows CCP to be grouped according to antibody reactivity patterns against 11 SARS-CoV-2 antigens. Unsupervised K-means analysis, via the gap statistics, as well as hierarchical clustering analysis revealed three main clusters with distinct reactivity intensities and patterns. These patterns were not recapitulated by adjusting the VITROS CoV2T or RVPNT assay thresholds. Plasma classified by COVAM reactivity patterns offers potential to improve CCP therapeutic efficacy CoV2T alone. The use of a SARS-CoV-2 antigen array can qualify CCP for administration as a treatment for acute COVID-19, and interrogate vaccine immunogenicity and performance in preclinical, clinical studies, and routine vaccination to identify antibody responses predictive of protection from infection and disease.

Disagreement between Cardiac Troponin Tests Yielding a Higher Incidence of Myocardial Injury in the Emergency Setting.

Differences in patient classification of myocardial injury between high-sensitivity cardiac troponin (hs-cTn) assays have largely been attributed to assay design and analytical sensitivity aspects. Our objective was to compare Ortho Clinical Diagnostics’ (OCD) hs-cTnI assay to OCD’s contemporary/conventional assay (cTnI ES) and another hs-cTnI assay (Abbott hs-cTnI) in samples obtained from different emergency departments (EDs). Two different sample types were evaluated (lithium heparin and ethylenediaminetetraacetic acid (EDTA) plasma) in a non-selected ED population (study 1, n = 469 samples) and in patients for which ED physicians ordered cardiac troponin testing (study 2, n = 1147 samples), from five different EDs. The incidence of injury in study 1 was higher with the OCD hs-cTnI assay (30.9%; 95% CI: 26.9 to 35.2) compared to that of the Abbott hs-cTnI (17.3%; 95% CI: 14.1 to 21.0) and the OCD cTnI ES (15.4%; 95% CI: 12.4 to 18.9) assays, with repeat testing identifying 4.8% (95% CI: 3.0 to 7.5) of the OCD hs-cTnI results with poor reproducibility. In study 2, 4.6% (95% CI: 3.5 to 6.0) of the results were not reported for the OCD hs-cTnI assay (i.e., poor reproducibility) with 12.7% (95%CI: 8.7 to 17.8) of the OCD hs-cTnI results positive for injury being negative for injury with the Abbott hs-cTnI assay. In summary, the OCD hs-cTnI assay yields higher rates of biochemical injury with a higher rate of poor reproducible results in different ED populations.

Clinical evaluation of the antibody response in patients with COVID-19 using automated high-throughput immunoassays

Several automated high-throughput immunoassays for detecting anti-SARS-CoV-2 antibodies by a semi-quantitative approach have been commercialized. In this study, we describe the timeline of the antibody response in patients with RT-PCR-confirmed COVID-19. A total of 292 sequential serum samples from 33 Japanese patients were retrospectively analyzed using four test kits for SARS-CoV-2: the Abbott SARS-CoV-2 IgG assay (Abbott), Elecsys® Anti-SARS-CoV-2 assay (Roche Diagnostic), and VITROS® Anti-SARS-CoV-2 Total and IgG assays (Ortho Clinical Diagnostics). All automated immunoassays could equivalently identify positive sera collected within 2 weeks after symptom onset (99.3%–100%). In addition, the S protein-based automated immunoassay, the VITROS® Anti-SARS-CoV-2 Total assay, may play a complementary role in evaluating passive antibody therapies or vaccines against SARS-CoV-2, although further research is required.

Mesenchymal stromal cell treatment of donor kidneys during ex vivo normothermic machine perfusion: A porcine renal autotransplantation study.

Normothermic machine perfusion (NMP) of injured kidneys offers the opportunity for interventions to metabolically active organs prior to transplantation. Mesenchymal stromal cells (MSCs) can exert regenerative and anti-inflammatory effects in ischemia-reperfusion injury. The aims of this study were to evaluate the safety and feasibility of MSC treatment of kidneys during NMP using a porcine autotransplantation model, and examine potential MSC treatment-associated kidney improvements up to 14days posttransplant. After 75min of kidney warm ischemia, four experimental groups of n=7 underwent 14h of oxygenated hypothermic machine perfusion. In three groups this was followed by 240min of NMP with infusion of vehicle, 10million porcine, or 10million human adipose-derived MSCs. All kidneys were autotransplanted after contralateral nephrectomy. MSC treatment did not affect perfusion hemodynamics during NMP or cause adverse effects at reperfusion, with 100% animal survival. MSCs did not affect plasma creatinine, glomerular filtration rate, neutrophil gelatinase-associated lipocalin concentrations or kidney damage assessed by histology during the 14days, and MSCs retention was demonstrated in renal cortex. Infusing MSCs during ex vivo NMP of porcine kidneys was safe and feasible. Within the short posttransplant follow-up period, no beneficial effects of ex vivo MSC therapy could be demonstrated.

Acute Phase Response and Non-Reproducible Elevated Concentrations with a High-Sensitivity Cardiac Troponin I Assay.

High-sensitivity cardiac troponin (hs-cTn) testing has enabled physicians to make earlier diagnostic and prognostic decisions in the hospital setting than previous cardiac troponin assays. Analytical improvements have permitted one to measure cardiac troponin precisely in the nanogram per litre (ng/L) range with hs-cTn assays which has resulted in fast 0/1-h and 0/2-h algorithms for ruling-in and ruling-out myocardial infarction. Although analytical interferences that affect the reporting of hs-cTn are uncommon, not all hs-cTn assays are designed the same nor have undergone the same clinical and analytical validations. Here, after investigating an initial case of discrepant hs-cTnI results, we report that patients with an acute phase response (e.g., patients with inflammatory or infectious illnesses) can yield high and non-reproducible results with the Ortho Clinical Diagnostics hs-cTnI assay. Compared to Abbott Diagnostics hs-cTnI, Ortho Clinical Diagnostics hs-cTnI assay misclassifies biochemical injury in approximately 10% of the population being assessed for myocardial injury with imprecise results in approximately half of this population (i.e., 5%). In conclusion, caution is warranted in interpreting Ortho Clinical Diagnostics hs-cTnI alone in patients being evaluated for myocardial injury, especially in patients whose primary presentation is related to an acute phase response and not an acute coronary syndrome symptom.

Selecting COVID-19 convalescent plasma for neutralizing antibody potency using a high-capacity SARS-CoV-2 antibody assay.

BackgroundEfficacy of COVID‐19 convalescent plasma (CCP) is hypothesized to be associated with the concentration of neutralizing antibodies (nAb) to SARS‐CoV‐2. High capacity serologic assays detecting binding antibodies (bAb) have been developed; nAb assays are not adaptable to high‐throughput testing. We sought to determine the effectiveness of using surrogate bAb signal‐to‐cutoff ratios (S/Co) in predicting nAb titers using a pseudovirus reporter viral particle neutralization (RVPN) assay.MethodsCCP donor serum collected by three US blood collectors was tested with a bAb assay (Ortho Clinical Diagnostics VITROS Anti‐SARS‐CoV‐2 Total, CoV2T) and a nAb RVPN assay. Prediction effectiveness of various CoV2T S/Co criteria was evaluated for RVPN nAb NT50 titers using receiver operating characteristics.ResultsSeven hundred and fifty‐three CCPs were tested with median CoV2T S/Co and NT50 of 71.2 of 527.5. Proportions of donors with NT50 over target nAb titers were 86% ≥1:80, 76% ≥1:160, and 62% ≥1:320. Increasing CoV2T S/Co criterion reduced the sensitivity to predict NT50 titers, while specificity to identify those below increased. As target NT50 titers increase, the CoV2T assay becomes less accurate as a predictor with a decline in positive predictive value and rise in negative predictive value.ConclusionSelection of a clinically effective nAb titer will impact availability of CCP. Product release with CoV2T assay S/Co criterion must balance the risk of releasing products below target nAb titers with the cost of false negatives. A two‐step testing scheme may be optimal, with nAb testing on CoV2T samples with S/Cos below criterion.

The seroprevalence of SARS-CoV-2 in a rural southwest community.

The true prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has been difficult to determine due to limited testing, inconsistent symptom severity, and asymptomatic infections. Systematic investigation of the prevalence of SARS-CoV-2 has been limited to urban environments and large academic centers. Limited data on the seroprevalence of SARS-CoV-2 is available for those who live in a rural community setting, leaving rural practitioners to extrapolate the epidemiology of COVID-19 to a nonhomogeneous population. To determine the seroprevalence of SARS-CoV-2 in a community setting. The secondary objective of this study was to describe the difference in infection rate and reverse transcription polymerase chain reaction (RT-PCR) testing in the same rural community. A prospective convenience sample of community members and healthcare workers from the Kingman, Arizona area were tested for SARS-CoV-2-specific antibodies using a lateral flow immunoassay with theVITROS Anti-SARS-CoV-2 IgG test (Ortho-Clinical Diagnostics, Inc.) from September 28, 2020 to October 09, 2020. Upon recruitment, participants were asked to complete a demographic survey assessing socioeconomic status, comorbidities, and COVID-19 symptoms in the preceding twomonths. Following enrollment, a retrospective chart review was completed to determine the percentage of patients who had undergone previous SARS-CoV-RT-PCR testing. A total of 566 participants were included in the final analysis: 380 (67.1%) were women, 186 (32.9%) were men, a majority (458; 80.9%) self-identified as White, and 303 (53.5%) were employed as healthcare professionals. Seroprevalence of SARS-CoV-2 was found to be 8.0% (45 of 566) across the sample and 9.9% (30 of 303) in healthcare workers. No statistical difference in seroprevalence was found between men and women, healthcare workers andother participants, amongst racial groups, by socioeconomic status, by comorbid conditions, or by education level. Among the participants, 108 (19.1%) underwent previous RT-PCR testing. Of the 45 patients who were antibody positive, 27 (60%) had received a previous RT-PCR test, with 20 (44.4%) testing positive for SARS-CoV-2. Participants with symptoms of anosmia/ageusia (p<0.001), chest congestion (p=0.047), fever (p=0.007), and shortness of breath (p=0.002) within the past twomonths were more likely to have antibodies to SARS-CoV-2. Only 8% of 566 participants in this rural community setting were found to have antibodies for SARS-CoV-2. A large minority (18; 40%) of patients testing seropositive for SARs-CoV-2 had never received a prior test, suggesting that the actual rates of infection are higher than publicly available data suggest. Further large-scale antibody testing is needed to determine the true prevalence of SARS-CoV-2 in the rural setting.

Validation of COVID-19 serologic tests and large scale screening of asymptomatic healthcare workers

ObjectivesSerologic testing for SARS-CoV-2 is an important element in the fight to slow the COVID-19 pandemic. This study aimed to validate two serologic tests for total (IgM, IgG, IgA) SARS-CoV-2 antibodies, (i) the Ortho-Clinical Diagnostics Anti-SARS-CoV-2 Total Antibody assay for the Vitros 5600 analyzers and (ii) a manual laboratory developed ELISA (FDA EUA pending), for use in parallel orthogonal testing of asymptomatic healthcare workers and affiliates of the University of Maryland Medical System. Design and MethodsValidation and verification of the two tests was performed using samples from hospitalized patients that were found to be PCR positive for SARS-CoV-2, samples pre-COVID-19, and samples from individuals with current/previous infections with other viruses. Healthcare workers and affiliates from across the University of Maryland Health System were provided testing free of charge and their results were reported as reactive or non-reactive if the two tests were concordance, or indeterminate if the results were discordant. ResultsValidation testing found the Ortho Vitros test to be 100% (73/73) sensitive, and 99.3% (152/153) specific, while the UMMC ELISA was found to be 97.6% (204/209) sensitive and 100% (288/288) specific. Real world testing among 8399 healthcare workers found that 2.9% (247/8399) of healthcare workers were positive for anti- SARS-CoV-2 antibodies by both tests. An indeterminate rate of 1.1% (91/8399), in which one test reported reactive results, and one as non-reactive was also seen. ConclusionsParallel orthogonal testing improves the positive and negative predictive value of serologic testing in populations with low prevalence. The use of an indeterminate result from parallel orthogonal testing allows for the follow-up and re-testing, which helps resolve discrepancies between assays.

Evaluating the Performance of Four SARS-CoV-2 Commercial Chemiluminescence Immunoassays

Background: COVID-19 is a pandemic of serious global threat that forced test developers to flood the market with various diagnostic assays that have been independently validated. Objectives: This study aims at assessing the performance of four SARS-CoV-2 chemiluminescence immunoassays. Methodology: The present study included sera from 96 Polymerase Chain Reaction (PCR)–confirmed COVID-19 cases collected at 2 time periods (5-9 days and 9-14 days post symptom onset) during patient follow-up, and 30 control sera from COVID-19 PCR–negative individuals. All sera were tested for SARS-CoV-2 antibodies using four high-throughput commercially available chemiluminescence immunoassays: YHLO Biotech Co, Ltd China (IgM and IgG); Abbott, Abbott USA (IgG); Roche, Roche US (total: IgM, IgG, and IgA), and Ortho, Ortho Clinical Diagnostics, USA (total and individual IgG). Results: For the detection of total antibodies (IgM, IgG, and IgA), the highest sensitivities were for Ortho followed by Roche assays (91.6% and 84.3% in 5-9 days period, respectively) raised to 96.8% and 92.7% in 9-14 days respectively with significant difference P-value &lt;0.00001. Ortho, Roche, and YHLO iFlash (IgM) assays had specificities of 100%, 100%, and 90.3% respectively. Roche (Total) and Ortho (Total) assays showed perfect categorical agreement (94.4% in 5-9 days, and 96.4% in 9-14 days). As for the detection of individual IgG antibodies, the Abbott assay had the highest sensitivity (91.6% in 5-9 days, and 93.7% in 9-14 days), followed by Ortho and YHLO iFlash assays (84.3%, and 83.3% in 5-9 days respectively) that increased to 89.5% and 88.5% in 9-14 days respectively. Ortho assay was the best in specificity (100%), followed by Abbott (98.8%) and YHLO iFlash (96.3%). YHLO iflash (IgG) and Ortho (IgG) showed perfect agreement (96.8%) in the 2 time frames. Conclusion: Ortho assay showed the best performance in detecting total antibodies with perfect match to Roche assay, while Abott assay was the best performing in detecting individual IgG with perfect match to Ortho assay rendering them to be efficient diagnostic tools

Serosurveillance of SARS-CoV-2 among the Healthcare Workers of a Tertiary Care Teaching Institution during the Post Lockdown Phase in Central Kerala, India

Introduction: The hallmark of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection is high infectivity, pre symptomatic transmission and asymptomatic prevalence which could result in high cumulative numbers of infections, hospitalisations, and deaths. Kerala was the first state to confirm community transmission in July 2020. Healthcare Workers (HCWs) being in the forefront in the war against Coronavirus Disease-2019 (COVID-19) are more prone to acquire the infection and could possibly be asymptomatic sources for cluster formation. Knowing the development of immunity as shown by the presence of anti COV-2 antibodies in the population contributes to the epidemiological understanding of the disease. Aim: To determine the pattern of seropositivity of SARS-CoV-2 among the HCWs at Jubilee Mission Medical College and Research Institute, Thrissur, Kerala, India, six months after revoking the lockdown. Materials and Methods: This cross-sectional study was carried out among 423 HCWs of the medical college from September 5th to December 15th, 2020. Multistage sampling was done with the hospital block as the first stage and departments as the second stage. Blood sample was collected and Anti SARS COV-2 IgG antibody testing which targets the Spike Protein 1 (SP1) was done using the vitros chemiluminescence platform (Orthoclinical diagnostics, USA). For the summary of demographic characteristics, continuous variables were summarised as mean values and Standard Deviation (SD) while categorical variables were summarised as proportions. The χ2 test was used for comparing the epidemiological features between positive and negative cases. Chi-square test for trend analysis was done for exploring the relationship of the degree of severity with test positivity. All analyses were conducted using Statistical Package for the Social Sciences (SPSS) version 25.0. Results: Jubilee Mission Medical College had 2785 working staff at the time of study. A total of 423 staff consented and their samples were tested. Thirty seven staff members tested positive for COVID-19 antibody, yielding an overall prevalence of 8.75% (95% CI, 6.23-11.86). A 86.5% (32/37) of them were having a history of COVID-19 Antigen/Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) Positivity. A statistically significant linear trend (p-value=0.00001) was observed, between seropositivity and the degree of severity of COVID-19. Among the various factors which increase the risk of seroconversion, history of undergoing quarantine (p-value &lt;0.001), contact with a confirmed case (p-value=0.002), contact with a caregiver for COVID-19 (p-value=0.001) and history of upper respiratory symptoms (p-value=0.001), were found to be significantly associated with positive serology. Conclusion: The pattern of seropositivity across the different category of HCWs observed in the present study showed a higher prevalence among nurses. Being an educational institution, it was obligatory to train all the elements of care delivery to the future generation of HCWs. Acquiring experience from a small but relevant sample was expected to facilitate larger community study envisaged in peripheral areas Jubilee Mission Hospital served.

Prevalence of liver fibrosis and cirrhosis in 699 Moroccan patients with chronic hepatitis C.

Introductionchronic hepatitis C (CHC) can cause severe complications, including fibrosis and cirrhosis. Very little is known about the prevalence of these complications in the Moroccan population.Methodsthe prevalence of liver fibrosis and cirrhosis using a non-invasive blood test (FibroTest and ActiTest) was studied in 699 Moroccan patients with CHC for 4 years (from January 2014 to December 2017). The serum immunological markers: α2-macroglobulin, haptoglobin, apolipoprotein A1 were analyzed nephelometrically on BN ProSpec® System. The serum biochemical markers: γ-glutamyltransferase, alanine aminotransferase, and bilirubin were performed using the VITROS® Chemistry System Ortho Clinical Diagnostic. A 699 patients with CHC were identified.Resultsthe overall prevalence of cirrhosis (F4) was estimated at 31.8%. Thirteen point nine percent (13.9%) of patients with cirrhosis had a risk of developing esophageal varices and a 3.3% risk of developing primary liver cancer. The association between cirrhosis and age showed an increase in prevalence after age 55 years old [OR=7.68(95%CI=4.9-12.2); p<0.0001]. No significant association for cirrhosis was found for sex.Conclusionaccording to the results of FibroTest, 32% of patients with CHC had cirrhosis. The older age was independently associated with liver cirrhosis.

Analytical and clinical evaluation of four commercial SARS-CoV-2 serological immunoassays in hospitalized patients and ambulatory individuals

BackgroundThis study aimed to compare four anti-SARS-CoV-2 immunoassays in populations presenting different clinical severity levels. MethodsThree populations were included: “severe-to-critical” ICU-hospitalized patients (n = 18), “mild-to-moderate” hospitalized patients (n = 16) and non-hospitalized symptomatic patients (n = 24). Four commercial immunoassays were analyzed and validated: anti-IgG ARCHITECT® (Abbott), anti-Total antibodies (Ab) VITROS® (Ortho Clinical Diagnostics), anti-IgG NovaLisa® (NovaTec Immundiagnostica) and Healgen® IgM and IgG (Zhejiang Orient Gene Biotech). Sensitivities were evaluated according to days post-symptoms onset (pso). Specificities were evaluated on SARS-CoV-2-negative control sera collected before January 2020. ResultsA majority of severe-to-critically ill patients showed detectable Ab already at day 14 and sensitivities reached 100 % after 22 days pso. For patients with “mild-to-moderate” illness, sensitivities increased by at least 5-fold from day 0 to day 14 pso. Non-hospitalized symptomatic individuals already seroconverted at day 14 days pso with 100 % sensitivities for Total Ab VITROS®. Specificities were evaluated at 97 % for ARCHITECT® and NovaLisa®, 98 % for VITROS® and at 94 % for Healgen® combined IgM and IgG. Five “severe-to-critically” ill patients presented high positive Ab levels for at least 16 weeks pso. ConclusionThe Ab levels and the evaluated sensitivities, representing the true positive rate, increased overtime and were related to the COVID-19 severity. Automated Total Ab immunoassay showed better sensitivities and specificity for immunological surveillance and vaccine evaluation.

PREVALENCE OF IRREGULAR RED CELLANTIBODIES IN HEALTHY BLOOD DONORS ATTENDING A TERTIARY CARE HOSPITAL IN SOUTH INDIA

Introduction: Red cell antibodies that are found normally in human serum are considered naturally occurring and those are anti A and anti B. All other antibodies directed against RBC antigens are considered “unexpected or irregular". Aim: This study is aimed to evaluate the prevalence of the anti-red blood cell antibodies among healthy blood donors. Material and Methods: Antibody screening and identification was done using commercially available 3 cell and 11 cell reagent cells (0.8% Surgiscreen, Ortho Clinical Diagnostics Limited, USA and Low ionic Strength Saline Ortho Bliss with AHG Cassettes) in antihuman globulin phase. Results: A total of 36,684 donors were screened for the presence of irregular erythrocyte antibodies. Among these donors, twenty donors showed presence of alloantibodies in their serum (0.054%). Most frequent alloantibodies identified were from Lewis blood group system. The results showed statistically a higher prevalence of RBC alloantibodies in males than in females. Conclusion: Screening for presence of alloantibodies in donor blood is important to provide compatible blood products and to avoid transfusion reactions.