Validation of the New MINI-CUBE for Clinic Determination of Erythrocyte Sedimentation Rate.

Background: Erythrocyte sedimentation rate (ESR) indirectly measures blood fibrinogen, and it is altered by all those pathological conditions that modify the aggregation of red blood cells. The international guidelines by the International Council for Standardization in Hematology (ICSH) define the Westergren method as the gold standard for ESR, although it is completely operator-dependent, time-consuming, and requires a patient's blood consumption. Therefore, the validation of new ESR analyzers is needed. The aim of this study is the validation of a new automated ESR analyzer, MINI-CUBE (DIESSE, Diagnostica Senese, Italy). Methods: The samples (n = 270) were collected at the University Hospital of the University of Rome Tor Vergata. A comparison between the automated instrument and the gold standard was performed. Statistical analyses were processed by MedCalc software. Results: The comparison analysis performed on the overall samples reported a good agreement, showing a Spearman rank correlation coefficient of 0.94 (P < 0.001), compared to the Westergren test. The Bland-Altman analysis showed a mean bias of 1.5 (maximum (max.):19.6; minimum (min.): -16.6). Inter-run (level 1 coefficient of variation (CV): 4.9%; level 2 CV: 0.8%), intra-run (level 1 CV: 21.1%; level 2 CV: 3.2%), and inter-instrument (level 1 CV: 27.1%; level 2 CV: 5.6%) precision were also assessed. The hematocrit value did not interfere with the analysis: Spearman rank correlation coefficient of 0.929 (P < 0.001); mean bias of 1.3 (max.:18.3; min.: -15.6). Conclusions: Overall results from MINI-CUBE asserted a good correlation rate with the gold standard, and it could be considered an accurate, and objective alternative for the Westergren test.

The Antibodies' Response to SARS-CoV-2 Vaccination: 1-Year Follow Up.

The use of vaccines has allowed the containment of coronavirus disease 2019 (COVID-19) at a global level. The present work aims to add data on vaccination by evaluating the level of neutralizing antibodies in individuals who have received a three-vaccination series. For this purpose, we ran a surveillance program directed at measuring the level of IgG Abs against the Receptor Binding Domain (RBD) and surrogate virus neutralizing Ab (sVNT) anti-SARS-CoV-2 in the serum of individuals undergoing vaccination. This study was performed on employees from the University of Rome Tor Vergata and healthcare workers from the University Hospital who received the Vaxzevria vaccine (n = 56) and Comirnaty vaccine (n = 113), respectively. After the second dose, an increase in both RBD and sVNT Ab values was registered. In individuals who received the Comirnaty vaccine, the antibody titer was about one order of magnitude higher after 6 months from the first dose. All participants in this study received the Comirnaty vaccine as the third dose, which boosted the antibody response. Five months after the third dose, nearly one year from the first injection, the antibody level was >1000 BAU/mL (binding antibody units/mL). According to the values reported in the literature conferring protection against SARS-CoV-2 infection, our data indicate that individuals undergoing three vaccine doses present a low risk of infection.

Performance Evaluation of the New Chemiluminescence Immunoassay CL-1200i for HBV, HIV Panels.

Infectious diseases such as HIV and HBV are a global concern for their impact in terms of public health and costs for national health services. A central role in contrasting the spread of the infections is represented by timely diagnosis. The speed of detection depends on several factors including the type of test used. Antibody response to hepatitis B surface antigens (anti-HBs) is an important serological marker used for HBV-infection detection. The aim of this study was to compare the performance of the Abbott system and of the new analyser Mindray 1200i in the detection of HBV- and HIV-infections. Clinical serum samples were collected from patients randomly selected from PTV University Hospital of University of Rome "Tor Vergata" and tested for HBV and HIV antibodies. Samples were evaluated by Mindray Cl 1200i CLIA screening tests for HBV and HIV and the results were compared with the Abbott Architect analytical system, the routine instrument of the hospital clinical biochemistry laboratory. Precision study, linearity, and carryover were performed on the results obtained. The agreement between the results of the Abbott and Mindray CLIA ranged from 99% to 100% and the discrepancy rate from 0% to 1%. The measurements demonstrated that the Mindray CL-1200i platform offers high-level performance with accurate and consistent test results and could represent a valuable tool if implemented in routine analysis.

Validation of a quantitative lateral flow immunoassay (LFIA)-based point-of-care (POC) rapid test for SARS-CoV-2 neutralizing antibodies.

With the widespread use of coronavirus disease 2019 (COVID-19) vaccines, a rapid and reliable method to detect SARS-CoV-2 neutralizing antibodies (NAbs) is extremely important for monitoring vaccine effectiveness and immunity in the population. The purpose of this study was to evaluate the performance of the RapiRead™ reader and the TestNOW™ COVID-19 NAb rapid point-of-care (POC) test for quantitative measurement of antibodies against the spike protein receptor-binding domain of severe respiratory syndrome coronavirus 2 (SARS-CoV-2) in different biological matrices compared to chemiluminescence immunoassay (CLIA) methods. Ninety-four samples were collected and analyzed using a RapiRead™ reader and TestNOW™ COVID-19 NAb kits for detecting neutralizing antibodies, and then using two CLIAs. The data were compared statistically using the Kruskal-Wallis test for more than two groups or the Mann-Whitney test for two groups. Specificity and sensitivity were evaluated using a receiver operating characteristic (ROC) curve. Good correlation was observed between the rapid lateral flow immunoassay (LFIA) test system and both CLIA methods. RapiRead™ reader/TestNOW™ COVID-19 NAb vs. Maglumi: correlation coefficient (r) = 0.728 for all patients; r = 0.841 for vaccinated patients. RapiRead™ reader/TestNOW™ COVID-19 NAb vs. Mindray: r = 0.6394 in all patients; r = 0.8724 in vaccinated patients. The time stability of the POC serological test was also assessed considering two times of reading, 12 and 14 minutes. The data revealed no significant differences. The use of a RapiRead™ reader and TestNOW™ COVID-19 NAb assay is a quantitative, rapid, and valid method for detecting SARS-CoV-2 neutralizing antibodies and could be a useful tool for screening studies of SARS-CoV-2 infection and assessing the efficacy of vaccines in a non-laboratory context.

Performance evaluation of four surrogate Virus Neutralization Tests (sVNTs) in comparison to the in vivo gold standard test.

BACKGROUND: Several commercial surrogate Virus Neutralization Tests (sVNTs) have been developed in the last year. Neutralizing anti-SARS-CoV-2 antibodies through interaction with Spike protein Receptor Binding Domain (S-RBD) can block the virus from entering and infecting host cells. However, there is a lack of information about the functional activity of SARS-CoV-2 antibodies that may be associated with protective responses. For these reasons, to counteract viral infection, the conventional virus neutralization test (VNT) is still considered the gold standard. The aim of this study was to contribute more and detailed information about sVNTs' performance, by determining in vitro the anti-SARS-CoV-2 neutralizing antibody concentration using four different commercial assays and then comparing the obtained data to VNT. METHODS: Eighty-eight samples were tested using two chemiluminescence assays (Snibe and Mindray) and two ELISA assays (Euroimmun and Diesse). The antibody titers were subsequently detected and quantified by VNT. RESULTS: The overall agreement between each sVNT and VNT was 95.45% for Euroimmun and 98.86% for Diesse, Mindray and Snibe. Additionally, we investigated whether the sVNTs were closer to the gold standard than traditional anti-SARS-CoV-2 antibody assays S-RBD or S1 based, finding a higher agreement mean value for sVNTs (98.01 ± 1.705% vs 95.45 ± 1.921%; p < 0.05). Furthermore, Spearman's statistical analysis for the correlation of sVNT versus VNT showed r = 0.666 for Mindray; r = 0.696 for Diesse; r = 0.779 for Mindray and r = 0.810 for Euroimmun. CONCLUSIONS: Our data revealed a good agreement between VNT and sVNTs. Despite the VNT still remains the gold standard, the sVNT might be a valuable tool for screening wider populations.

Evaluation of serological anti-SARS-CoV-2 chemiluminescent immunoassays correlated to live virus neutralization test, for the detection of anti-RBD antibodies as a relevant alternative in COVID-19 large-scale neutralizing activity monitoring.

The Spike-Receptor Binding Domain (S-RBD) is considered the most antigenic protein in SARS-CoV-2 and probably the key player in SARS-CoV-2 immune response. Quantitative immunoassays may help establish an anti-RBD Abs threshold as an indication of protective immunity. Since different immunoassays are commercial, the standard reference method for the neutralizing activity is the live Virus Neutralization Test (VNT). In this study, anti-RBD IgG levels were detected with two chemiluminescent immunoassays in paucisymptomatic, symptomatic and vaccinated subjects, and their neutralizing activity was correlated to VNT titer, using SARS-CoV-2 original and British variant strains. Both immunoassays confirmed higher anti-RBD Abs levels in vaccinated subjects. Furthermore, despite different anti-RBD Abs median concentrations between the immunoassays, a strong positive correlation with VNT was observed. In conclusion, although the SARS-CoV-2 immune response heterogeneity, the use of immunoassays can help in large-scale monitoring of COVID-19 samples, becoming a valid alternative to VNT test for diagnostic routine laboratories.

Performance evaluation of the new Chemiluminescence Immunoassay CL-1200i Thyroid Panel.

Aim of this work was to verify the analytical performance of thyroid panel tests measured by chemiluminescence immunoassay (CLIA) CL-1200i and to validate its efficacy as laboratory test for thyroid disorder.Serum samples were obtained by standard centrifugation, thawed and assayed in a blinded fashion, and in a single batch. This study compares the values of thyroid panel tests measured by Mindray CL-1200i chemiluminescent system to the Abbott platforms for TSH, FT3, FT4, and Beckman Coulter for Tg, TgAb, and TPOAb on patient serum samples. A total of 180 randomly selected patients including both hospitalized and ambulatory patients from the Policlinico Tor Vergata (PTV) of the University of Rome Tor Vergata were used. In all analyses performed, the thyroid panel tests of the Mindray platform showed discriminative ability to quantitatively assess the analyte involved in thyroid disease and disorder. This study verified that Mindray CL-1200i chemiluminescent system thyroid panel tests is a valid method for obtaining a quantitative analysis of thyroid disorders. It showed high diagnostic efficiency and could represent a valid tool with a potential reduction in time and workload for the diagnosis.

Antibody response to COVID-19 vaccine: A point of view that can help to optimize dose distribution.

The global strategy to control coronavirus disease is based on the availability of COVID-19 vaccines. More information about response to a single dose vaccine could help to better understand and optimize the management of the vaccine campaign. Workers from the University of Rome "Tor Vergata" and the University Hospital of University of Rome "Tor Vergata," were monitored during their vaccination program. Serum samples were collected between the first and second dose and after the second dose. University personnel has been vaccinated with two doses of Vaxzevria vaccine 12 weeks apart, while hospital personnel has been vaccinated with two doses of Comirnaty 3 weeks apart. IgG antibodies (Abs) against the Receptor Binding Domain (RBD) of the virus spike surface glycoprotein and neutralizing antibodies (NT) anti-SARS-CoV-2 that block the interaction between RBD and the surface receptor cellular angiotensin converting enzyme (ACE2) were measured using the CL-series Mindray chemiluminescent assays, respectively. Different amounts of antibodies produced after the two doses of vaccine were found. Individuals with a previous natural infection developed a higher Abs titer. Among the individuals with no history of past SARS-CoV-2 infection, 5% had an Abs level of the same order of magnitude of infected people, suggesting that they acquired the infection in an asymptomatic way. In such individuals, one dose of vaccine may be sufficient to obtain a protective immune response.

Serological anti-SARS-CoV-2 neutralizing antibodies association to live virus neutralizing test titers in COVID-19 paucisymptomatic/symptomatic patients and vaccinated subjects.

A large number of immunoassays have been developed to detect specific anti-SARS-CoV-2 antibodies; however, not always they are functional to neutralize the virus. The reference test for the anti-spike neutralizing antibodies (nAbs) ability to counteract the viral infection is the virus neutralization test (VNT). Great interest is developing on reliable serological assays allowing antibodies concentration and antibody protective titer correlation. The aim of our study was to detect nAbs serum levels in paucisymptomatic, symptomatic and vaccinated subjects, to find a cut-off value able to protect from virus infection. nAbs serum levels were detected by a competitive automated immunoassay, in association to VNT with the SARS-CoV-2 original and British variant strains. The median nAbs concentrations were: 281.3 BAU/ml for paucisymptomatics; 769.4 BAU/ml for symptomatics; 351.65 BAU/ml for the vaccinated cohort; 983 BAU/ml considering only the second dose vaccinated individuals. The original strain VNT analysis showed 1:80 median neutralization titers in paucisymptomatic and vaccinated subjects; 1:160 in symptomatic patients; 1:160 in the second dose groups. The British variant VNT analysis showed lower neutralization titers in paucisymptomatic and vaccinated groups (1:40); the same titer in symptomatic patients (1:160); the second dose group confirmed the original strain titer (1:160). In conclusion, our data showed optimal correlations with a proportional increase between neutralizing activity and antibody concentration, making nAbs detection a good alternative to virus neutralization assays, difficult to carry out in routine laboratories. Finally, ROC curve analysis established a cut-off of 408.6 BAU/ml to identify subjects with a low risk of infection.

Evaluation of S-RBD and high specificity ACE-2-binding antibodies on SARS-CoV-2 patients after six months from infection.

The antibody response to SARS-CoV-2 has not yet fully defined, but the availability of sensitive and specific serological assays is crucial to observe the presence of specific antibodies against the human receptor binding domain (S-RBD) and high specificity ACE-2-binding antibodies or neutralizing antibodies (NT) in response to vaccines. Indeed, these peculiar antibodies should prevent viral interaction between RBD and Angiotensin-Converting Enzyme 2 (ACE2) receptor, located on surface of host cells. In this study, 72 samples from 37 hospitalized COVID-19 patients and 35 not-hospitalized patients were analyzed longitudinally. The detection of S-RBD and NT antibodies was carried out using CLIA tests. Hospitalized patients showed elevated serum levels of S-RBD (97.22%) and NT (77.78%) antibodies, differently, not-hospitalized, who were paucisymptomatic or asymptomatic patients, showed lower serum levels of S-RBD (65.71%) and NT (38.14%) antibodies. The results suggest that the NT serum level is strongly related to disease severity (p < 0.001) and to the serum level of S-RBD antibodies (p < 0.0001).

Clinical validation of a second generation anti-SARS-CoV-2 IgG and IgM automated chemiluminescent immunoassay.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has proven to be extremely contagious and has spread rapidly all over the world. A key aspect in limiting the virus diffusion is to ensure early and accurate diagnosis. Serological assays could be an alternative in increasing testing capabilities, particularly when used as part of an algorithmic approach combined with molecular analysis. The aim of this study was to evaluate the diagnostic accuracy of a second generation chemiluminescent automated immunoassay able to detect anti-SARS-CoV-2 immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies. Data are carried out on healthy subjects and other infectious diseases pre-pandemic sera, as controls, and on two different coronavirus disease 2019 hospitalized patient groups (early and late infection time). Data obtained have been analyzed in terms of precision, linearity, sensitivity and specificity. Specificities are: 100% for anti-SARS-CoV-2 IgG and 98% for anti-SARS-CoV-2 IgM, in all patient groups. Sensitivities are: 97%, 100%, and 98% for anti-SARS-CoV-2 IgG and 87%, 83%, and 86% for anti-SARS-CoV-2 IgM in the early infection, in the late infection and in the total patient group, respectively. The Mindray anti-SARS-CoV-2 IgG and IgM assays demonstrated higher sensitivity and specificity, indicating that IgG and IgM simultaneous detection is useful even in the early phases of infection.

Evaluation of a new simultaneous anti-SARS-CoV-2 IgA, IgM and IgG screening automated assay based on native inactivated virus.

In addition to molecular testing, there is evolving interest for anti-SARS-CoV-2 antibodies serologic assays. Majority of them focus on IgM/IgG despite IgA important role in mucosal immunity. A simultaneous anti-SARS-CoV-2 IgA/IgG/IgM immunoassay, performed on an automated instrument by ELISA kit coated with native inactivated SARS-CoV-2, was detected on two control groups (negative swab healthcare workers; pre-pandemic healthy or with other viral infections individuals) and on two COVID-19 patient groups (early and late infection). Specificities were 100% in all groups, indicating no cross-reactivity with other infectious or pre-pandemic sera. Sensitivities were 94% in early infection group and 97% in total positive patient group, reaching 100% in late infection group. To our knowledge, this is the first technique based on native SARS-CoV-2. It is able to identify more positive samples than kits using recombinant antigens, therefore virus native epitopes as well as simultaneous anti-SARS-CoV-2 IgA/IgM/IgG detection could help to contain COVID-19 spreading.