Sensitivity of point-of-care IgM and IgG test in critically ill patients with SARS-Cov-2.
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SUBMITTER: Nguyen LS
PROVIDER: S-EPMC7512203 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundCongenital toxoplasmosis is a serious but preventable and treatable disease. Gestational screening facilitates early detection and treatment of primary acquisition. Thus, fetal infection can be promptly diagnosed and treated and outcomes can be improved.MethodsWe tested 180 sera with the Toxoplasma ICT IgG-IgM point-of-care (POC) test. Sera were from 116 chronically infected persons (48 serotype II; 14 serotype I-III; 25 serotype I-IIIa; 28 serotype Atypical, haplogroup 12; 1 not typed). These represent strains of parasites infecting mothers of congenitally infected children in the U.S. 51 seronegative samples and 13 samples from recently infected persons known to be IgG/IgM positive within the prior 2.7 months also were tested. Interpretation was confirmed by two blinded observers. A comparison of costs for POC vs. commercial laboratory testing methods was performed.ResultsWe found that this new Toxoplasma ICT IgG-IgM POC test was highly sensitive (100%) and specific (100%) for distinguishing IgG/IgM-positive from negative sera. Use of such reliable POC tests can be cost-saving and benefit patients.ConclusionsOur work demonstrates that the Toxoplasma ICT IgG-IgM test can function reliably as a point-of-care test to diagnose Toxoplasma gondii infection in the U.S. This provides an opportunity to improve maternal-fetal care by using approaches, diagnostic tools, and medicines already available. This infection has serious, lifelong consequences for infected persons and their families. From the present study, it appears a simple, low-cost POC test is now available to help prevent morbidity/disability, decrease cost, and make gestational screening feasible. It also offers new options for improved prenatal care in low- and middle-income countries.
| S-EPMC5501679 | biostudies-literature
Project description:The serological testing of anti-SARS-CoV-2 immunoglobulin G (IgG) and/or IgM is widely used in the diagnosis of COVID-19. However, its diagnostic efficacy remains unclear. In this study, we searched for diagnostic studies from the Web of Science, PubMed, Embase, CNKI, and Wanfang databases to calculate the pooled diagnostic accuracy measures using bivariate random-effects model meta-analysis. As a result, 22 from a total of 1613 articles, including 2282 patients with SARS-CoV-2 and 1485 healthy persons or patients without SARS-CoV-2, were selected for a meta-analysis. Pooled sensitivity, specificity, and area under curve of the summary receiver operator curve (SROC) were: (a) 0.85 (95% confidence interval [CI]: 0.79-0.90), 0.99 (95% CI: 0.98-1.00), and 0.99 (95% CI: 0.97-0.99) for anti-SARS-CoV-2 IgG and (b) 0.74 (95% CI: 0.65-0.81), 0.99 (95% CI: 0.97-1.00), and 0.95 (95% CI: 0.93-0.97) for IgM. A subgroup analysis among detection methods indicated the sensitivity of IgG and IgM using enzyme-linked immunosorbent assay were slightly lower than those using gold immunochromatography assay (GICA) and chemiluminescence immunoassay (P > .05). These results showed that the detection of anti-SARS-CoV-2 IgG and IgM had high diagnostic efficiency to assist the diagnosis of SARS-CoV-2 infection. And, GICA might be used as the preferred method for its accuracy and simplicity.
| S-EPMC7361902 | biostudies-literature
Project description:The ongoing global pandemic of SARS-CoV-2 has promoted to develop novel serological testing technologies since they can be effectively complementary to RT-PCR. Here, a new all-fiber Fresnel reflection microfluidic biosensor (FRMB) was constructed through combining all-fiber optical system, microfluidic chip, and multimode fiber bio-probe. The transmission of the incident light and the collection and transmission of Fresnel reflection light are achieved using a single-multi-mode fiber optic coupler (SMFC) without any other optical separation elements. This compact design greatly simplifies the whole system structure and improves light transmission efficiency, which makes it suitable for the label-free, sensitive, and easy-to-use point-of-care testing (POCT) of targets in nanoliter samples. Based on Fresnel reflection mechanism and immunoassay principle, both the SARS-CoV-2 IgM and IgG antibodies against the SARS-CoV-2 spike protein could be sensitively quantified in 7 min using the secondary antibodies-modified multimode fiber bio-probe. The FRMB performs in one-step, is accurate, label-free, and sensitive in situ/on-site detection of SARS-CoV-2 IgM or IgG in serum with simple dilution only. The limits of detection of SARS-CoV-2 IgM and SARS-CoV-2 IgG were 0.82 ng/mL and 0.45 ng/mL, respectively. Based on our proposed theory, the affinity constants of SARS-CoV-2 IgM or IgG antibody and their respective secondary antibodies were also determined. The FRMB can be readily extended as a universal platform for the label-free, rapid, and sensitive in situ/on-site measurement of other biomarkers and the investigation of biomolecular interaction.
| S-EPMC8286882 | biostudies-literature
Project description:In the ongoing COVID-19 pandemic, simple, rapid, point-of-care tests not requiring trained personnel for primary care testing are essential. Saliva-based antigen rapid tests (ARTs) can fulfil this need, but these tests require overnight-fasted samples; without which independent studies have demonstrated sensitivities of only 11.7 to 23.1%. Herein, we report an Amplified Parallel ART (AP-ART) with sensitivity above 90%, even with non-fasted samples. The virus was captured multimodally, using both anti-spike protein antibodies and Angiotensin Converting Enzyme 2 (ACE2) protein. It also featured two parallel flow channels. The first contained spike protein binding gold nanoparticles which produced a visible red line upon encountering the virus. The second contained signal amplifying nanoparticles that complex with the former and amplify the signal without any linker. Compared to existing dual gold amplification techniques, a limit of detection of one order of magnitude lower was achieved (0.0064 ng·mL-1). AP-ART performance in detecting SARS-CoV-2 in saliva of COVID-19 patients was investigated using a case-control study (139 participants enrolled and 162 saliva samples tested). Unlike commercially available ARTs, the sensitivity of AP-ART was maintained even when non-fasting saliva was used. Compared to the gold standard reverse transcription-polymerase chain reaction testing on nasopharyngeal samples, non-fasting saliva tested on AP-ART showed a sensitivity of 97.0% (95% CI: 84.7-99.8); without amplification, the sensitivity was 72.7% (95% CI: 83.7-94.8). Thus, AP-ART has the potential to be developed for point-of-care testing, which may be particularly important in resource-limited settings, and for early diagnosis to initiate newly approved therapies to reduce COVID-19 severity.
| S-EPMC8646336 | biostudies-literature
Project description:Diagnostic evaluation of specific antibodies against the SARS-CoV-2 virus is mainly based on spike (S) and nucleocapsid (N) proteins. Despite the critical functions in virus infection and contribution to the pattern of immunodominance in COVID-19, exploitation of the most abundant membrane (M) protein in the SARS-CoV-2 serology tests is minimal. This study investigated the recombinant M protein's immunoreactivity with the sera from COVID-19 convalescents. In silico designed protein was created from the outer N-terminal part (19 aa) and internal C-terminal tail (101-222 aa) of the M protein (YP_009724393.1) and was recombinantly produced and purified. The designed M protein (16,498.74 Da, pI 8.79) revealed both IgM and IgG reactivity with serum samples from COVID-19 convalescents in Western blot. In ELISA, more than 93% (28/30) of COVID-19 sera were positive for IgM detection, and more than 96% (29/30) were positive for specific IgG detection to M protein. Based on the capacity to provoke an immune response and its strong antigenic properties, as shown here, and the fact that it is also involved in the virion entry into host cells, the M protein of the SARS-CoV-2 virus as a good antigen has the potential in diagnostic purposes and vaccine design.
| S-EPMC8125631 | biostudies-literature
Project description:AimThis study investigated the humoral response against SARS-CoV-2 in patients needing intensive care unit (ICU) care compared with those on general medicine wards.Materials & methodsThe authors retrospectively reviewed 113 hospitalized patients with COVID-19. They assessed antibody response against five SARS-CoV-2 epitopes at 6-14 days post symptom onset in these patients.ResultsPatients with ICU admissions had decreased anti-nucleocapsid immunoglobulin (Ig)M and increased anti-spike IgG compared with patients not requiring the ICU. IgG levels were positively correlated with length of stay.ConclusionHigher levels of IgG against the spike protein correlate with COVID-19 disease severity and length of stay in hospitalized patients. This adds to the knowledge of biochemical response to clinical disease and may help predict ICU needs.
| S-EPMC8830355 | biostudies-literature
Project description:COVID-19 is caused by SARS-CoV-2 infection and was initially discovered in Wuhan. This outbreak quickly spread all over China and then to more than 20 other countries. SARS-CoV-2 fluorescent microsphere immunochromatographic test strips were prepared by the combination of time-resolved fluorescence immunoassay with a lateral flow assay. The analytical performance and clinical evaluation of this testing method was done and the clinical significance of the testing method was verified. The LLOD of SARS-CoV-2 antibody IgG and IgM was 0.121U/L and 0.366U/L. The specificity of IgM and IgG strips in healthy people and in patients with non-COVID-19 disease was 94%, 96.72% and 95.50%, 99.49%, respectively; and sensitivity of IgM and IgG strips for patients during treatment and follow-up was 63.02%, 37.61% and 87.28%, 90.17%, respectively. The SARS-CoV-2 antibody test strip can provide rapid, flexible and accurate testing, and is able to meet the clinical requirement for rapid on-site testing of virus. The ability to detect IgM and IgG provided a significant benefit for the detection and prediction of clinical course with COVID-19 patients.
| S-EPMC7534335 | biostudies-literature
Project description:ObjectivesTo describe the incidence of venous thromboembolism (VTE) in mechanically ventilated COVID-19 patients in an HIV endemic, resourced constrained setting. To describe the incidence of VTE in relation to HIV status and anticoagulant therapy, and to evaluate VTE-associated cardio-respiratory changes. To establish the contribution of HIV, anticoagulation therapy and other risk factors to mortality.DesignProspective descriptive study.SettingSingle-center tertiary teaching hospital.ParticipantsOne hundred and one consecutively admitted critically ill adult patients with COVID-19 acute respiratory distress syndrome.InterventionsPoint of care ultrasound (POCUS) assessment of the lower limbs and the cardio-respiratory system was performed on intensive care unit (ICU) admission and repeated if clinically indicated.Measurements and main resultsDVT was diagnosed by POCUS, whilst pulmonary embolism was diagnosed using a combination of clinical criteria and POCUS (echocardiography and chest wall ultrasound). VTE was diagnosed in 16/101 (16%) patients, despite 14/16 (88%) receiving prior therapeutic dosage of low molecular weight heparin. Clinically significant PE was diagnosed in 5/16 (31%) with 11/16 (69%) having DVT only. The majority of VTE patients, 12/16 (75%), demised 16/101 (16%) patients had HIV co-infection, and 4/16 (25%) with HIV had VTE. Valvular abnormalities were the most common cardiac abnormality with marked tricuspid regurgitation detected in 51/101 (51%). The absence of right atrial enlargement had a 93% negative predictive value for the absence of VTE. Univariate analysis did not demonstrate statistically significant individual risk factors for mortality.ConclusionsMechanically ventilated COVID- 19 patients at ICU admission had a low incidence of VTE (16%). Therapeutic dose anticoagulation did not reduce mortality compared to prophylactic dosage. In contrast to findings from other studies, no individual risk factor contributed significantly to mortality, likely due to small sample size. POCUS is an ideal screening tool to aid in the assessment of critically ill patients.
| S-EPMC10205134 | biostudies-literature
Project description:The COVID-19 pandemic, caused by the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), continues to spread worldwide. Serological testing for SARS-CoV-2-specific antibodies plays an important role in understanding and controlling the pandemic, notably through epidemiological surveillance. Well-validated and highly specific SARS-CoV-2 serological assays are urgently needed. We describe here the analytical and clinical performance of Vidas SARS-CoV-2 IgM and Vidas SARS-CoV-2 IgG, two CE-marked, emergency use authorization (EUA)-authorized, automated, qualitative assays for the detection of SARS-CoV-2-specific IgM and IgG, respectively. Both assays showed high within-run and within-laboratory precision (coefficients of variation < 11.0%) and very low cross-reactivity toward sera of patients with a past common coronavirus or respiratory virus infection. Clinical specificity determined on up to 989 prepandemic healthy donors was ≥99% with a narrow 95% confidence interval for both IgM and IgG assays. Clinical sensitivity was determined on up to 232 samples from 130 reverse transcriptase PCR (RT-PCR)-confirmed SARS-CoV-2 patients. The positive percent agreement (PPA) with SARS-CoV-2 PCR reached 100% at ≥16 days (Vidas SARS-CoV-2 IgM) and ≥32 days (Vidas SARS-CoV-2 IgG) of symptom onset. Combined IgM/IgG test results improved the PPA compared to each test alone. SARS-CoV-2 IgG seroconversion followed closely that of SARS-CoV-2 IgM and remained stable over time, while SARS-CoV-2 IgM levels rapidly declined. Interestingly, SARS-CoV-2-specific IgM and IgG responses were significantly higher in COVID-19 hospitalized versus nonhospitalized patients. Altogether, the Vidas SARS-CoV-2 IgM and IgG assays are highly specific and sensitive serological tests suitable for the reliable detection of past acute SARS-CoV-2 infections.
| S-EPMC8092742 | biostudies-literature
Project description:The clinical performance of the BD Veritor System for Rapid Detection of SARS-CoV-2 nucleocapsid antigen (Veritor), a chromatographic immunoassay used for SARS-CoV-2 point-of-care testing, was evaluated using nasal specimens from individuals with COVID-19 symptoms. Two studies were completed to determine clinical performance. In the first study, nasal specimens and either nasopharyngeal or oropharyngeal specimens from 251 participants with COVID-19 symptoms (≤7 days from symptom onset [DSO], ≥18 years of age) were utilized to compare Veritor with the Lyra SARS-CoV-2 PCR assay (Lyra). In the second study, nasal specimens from 361 participants with COVID-19 symptoms (≤5 DSO, ≥18 years of age) were utilized to compare performance of Veritor to that of the Sofia 2 SARS Antigen FIA test (Sofia 2). The positive, negative, and overall percent agreement (PPA, NPA, and OPA, respectively) were the primary outcomes. In study 1, the PPA for Veritor, compared to Lyra, ranged from 81.8 to 87.5% across the 0 to 1 and 0 to 6 DSO ranges. In study 2, Veritor had PPA, NPA, and OPA values of 97.4, 98.1, and 98.1%, respectively, with Sofia 2. Discordant analysis showed one Lyra positive missed by Veritor and five Lyra positives missed by Sofia 2; one Veritor positive result was negative by Lyra. Veritor met FDA emergency use authorization (EUA) acceptance criteria for SARS-CoV-2 antigen testing for the 0 to 5 and 0 to 6 DSO ranges (PPA values of 83.9% and 82.4%, respectively). Veritor and Sofia 2 showed a high degree of agreement for SARS-CoV-2 detection. The Veritor test allows for more rapid COVID-19 testing utilizing easy-to-collect nasal swabs but demonstrated <100% PPA compared to PCR.
| S-EPMC7771450 | biostudies-literature